Patent Application
20130065959
Safe and reliable means of removing microorganisms from the environment is a growing public health and agricultural concern. Existing methods for removing or reducing environmental microorganisms do not adequately control microorganisms that have the potential to cause disease or spoilage in the food and agriculture industries. Accordingly, there is a large need for new methods and compositions that can greatly reduce the presence of microorganisms in the environment.
This invention provides compositions and methods that meet these needs.
The invention relates to the discovery that an aqueous solution comprising peroxyacetic acid, lactic acid, and (optionally) sodium lauryl sulfate or another surfactant is surprisingly effective in reducing microbial contamination on the surfaces of items. The combination of the ingredients is much more effective at reducing attached microbes on an item than any one of the ingredients acting alone. Accordingly, the invention provides compositions and methods useful in contact surface sanitation. Sanitizing or disinfecting the surfaces control or reduces the presence of unwanted microorganisms on the surfaces of any fomite or other items. In a first aspect the invention provides methods of sanitizing or disinfecting surfaces by contacting the surface of an item with a sanitizing or disinfecting composition according to the invention.
The compositions according to the invention have a pH of 2.5 to 6.0 and comprise i) an organic peracid of the formula RC(O)OOH wherein R is methyl, ethyl, n-propyl, or s-propyl; ii) a 2-hydroxy organic acid selected from tartaric acid, citric acid, malic acid, mandelic acid, and lactic acid; iii) water; and optionally iv), an anionic surfactant. In preferred embodiments, the peracid is peroxyacetic acid (also known as peracetic acid or acetyl hydroperoxide), the organic acid is lactic acid (also known as 2-hydroxypropionic acid), and if present, the preferred anionic surfactant is sodium lauryl sulfate. Because aqueous compositions of peracids may exist in equilibrium with, or be formed from concentrated solutions of, hydrogen peroxide, their corresponding acid, and water, the aqueous compositions may also contain hydrogen peroxide and the corresponding acid (e.g., acetic acid in the case of peroxyacetic acid). The compositions may be provided as concentrates or in ready-to-use aqueous formulations. The compositions may also be provided as part of a kit for use in sanitizing items.
In some embodiments the items whose surfaces are sanitized or disinfected have a hard or soft surface which are at risk of contamination from microorganisms.
In some embodiments, the surface is a surface of an item found in a food processing environment (equipment and tools, e.g., harvesting, cutting boards, cutting knives and blades, and produce). The contacting can sanitize the surface of the item by greatly reducing the number of microbes, including any human pathogens, present or adhering to the surface of the item. The contacting can also serve to prevent spoilage of the item due to indigenous microbial contamination on its surface. The contacting can also serve to preserve the quality of the item by reducing off-odors, decay, and/or inhibiting the growth of indigenous microbes on the surface.
In another embodiment, the invention provides a method of disinfecting or preserving cut plants (flowers or cut trees) by contacting the plants with a composition according to the invention. In some embodiments, the composition is a solution is sprayed on the cut flowers. In other embodiments, the cut stem of the flowers or trunk of the tree (e.g., a pine, fir, or spruce tree) are placed in a solution according to the invention. In other embodiments, the compositions are used to treat the surfaces of living plants, including in hydroponic settings.
In some embodiments, seeds, sprouting seeds (e.g., prevent E. coli outbreaks for sprouts), leaves for ornamental plants (e.g. orchids), and nursery plants (e.g., to prevent mold) are contemplated to be treated or contacted with the sanitizing compositions according to the invention. In some embodiments, the sanitizing of the outer skin or surface of a berry, fruit, vegetable, or plant prior to extraction of juice (e.g., orange juice, citrus juice, apple juice, grape juice, tomato juice, vegetable juices) is contemplated by contacting the outer skin of the fruit or vegetable with a composition according to the invention. These treatments can serve to protect the health of the treated item or enhance its shelf-life by reducing spoilage.
In another aspect the invention provides a method of sanitizing plant-derived materials or their surfaces by contacting them with a composition according to the invention.
In yet another embodiment, the invention provides a method for sanitizing food, including, but not limited to fruits and vegetables, by contacting the food with a composition according to the invention. In some embodiments, the food is treated at home or less than one hour before cooking or any final food preparation prior to consumption.
In another aspect, the invention provides the compositions according to the invention in a packaging or format suitable for use in a method according to the invention.
The invention relates to the discovery that an aqueous composition comprising peroxyacetic acid and lactic acid is surprisingly effective in reducing microbial contamination on the surfaces of items. The combination of the ingredients is much more effective at reducing attached microbes on an item than any one of the ingredients acting alone.
Peroxyacetic acid antimicrobial activity relies on its high oxidizing potential. The mechanism of oxidation is the transfer of electrons, therefore the stronger the oxidizer, the faster the electrons are being transferred to the microorganism and the faster the microorganism is inactivated or killed. Therefore based on the table below peroxyacetic acid has a higher oxidation potential than chlorine sanitizers but less than that of ozone.
As diffusion of the molecule is slower than its half-life, peroxyacetic will react with any oxidizable compounds in its vicinity. It can damage virtually all types of macromolecules associated with a microorganism; for e.g. carbohydrates, nucleic acids (mutations), lipids (lipid peroxidation) and amino acids (e.g. conversion of Phe to m-Tyr and o-Tyr), and ultimately cause cell lysis. Conventionally, 2-hydroxy organic acids such as lactic acid that possess the chemical properties of oxidizable organic compounds would be taught away from being used together with a strong oxidizer, particularly with reference to peracids. Hence, it is particularly surprising to combine the peracetic acid and lactic acid in this invention and shown that the two compounds have synergistic effects rather than one counteracting against the other.
It must be noted that, as used in this specification and the appended claims, the singular forms “a,” “an” and “the” include plural referents unless the content clearly dictates otherwise. Thus, for example, reference to a “surfactant” includes two or more such surfactants.
Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which the invention pertains. All ranges are inclusive of the end values.
With reference to the aqueous solutions and methods of the invention, “peracid” and “organic peracid” refer to compounds of the structure RC(O)OOH in which R is an aliphatic group having from 1 to 3 carbon atoms. R may be methyl, ethyl, n-propyl, or s-propyl. A particularly preferred peracid is peracetic acid/peroxyacetic acid/PAA/(CH3C(O)OOH). Mixtures of the above organic peracids may be used.
In aqueous solutions, organic peracids exist in a chemical equilibrium with hydrogen peroxide and accordingly can be formed from the corresponding organic acids and hydrogen peroxide in the reaction:
RCOOH+H2O2RC(O)OOH+H2O
The equilibrium concentration of each reactant can be calculated from the equilibrium equation:
([RCOOOH] [H2O])/([RCOOH] [H2O2])=Kap (Eq. 1)
wherein: [RCOOOH] is the concentration of peracid in mole/L; [H2O] is the concentration of water in mole/L; [RCOOH] is the concentration of organic acid in mole/L; and [H2O2] is the concentration of hydrogen peroxide in mole/L; and Kap is the apparent equilibrium constant for the peracid equilibrium reaction (Equation I).
The apparent equilibrium constant, Kap, varies with both the peracid chosen and with temperature. Equilibrium constants for peracid formation can be found in D. Swern, ed., Organic Peroxides, Vol. 1, Wiley-Interscience, New York, 1970. At a temperature of 40° C., the apparent equilibrium constant for peroxyacetic acid is about 2.21. In accordance with this equilibrium reaction, organic peracid solutions comprise hydrogen peroxide and the corresponding organic acid in addition to the organic peracid.
When diluted, a relatively long period of time may lapse before a new equilibrium is achieved. For instance, equilibrium solutions that comprise about 5% peroxyacetic acid typically comprise about 22% hydrogen peroxide. Equilibrium solutions that comprise about 15% peroxyacetic acid typically comprise about 10% hydrogen peroxide. When these equilibrium solutions are diluted to solutions that comprise about 50 ppm of peroxyacetic acid, the solution produced by dilution of the 5% peroxyacetic acid solution comprises about 220 ppm of hydrogen peroxide, and the solution produced by dilution of 15% solution comprises about 33 ppm of hydrogen peroxide. Accordingly, in some embodiments, the sanitizing composition is provided as a concentrate which is diluted to the desired peracid concentration with water or with an aqueous solution comprising other components of the sanitizing solution according to the invention just prior to use. In some embodiments, the sanitizing compositions are provided as concentrates which are diluted just prior to use.
Peracids are readily commercially available in accordance with the above equilibrium. Peroxyacetic acid (CAS No. 79-21-0) is readily commercially available, for instance, as aqueous solution comprising peroxyacetic acid (35%), hydrogen peroxide (6.5%), acetic acid 64-19-7 (40%), sulfuric acid (about 1%) and water (about 17%) (all units w/w).
The 2-hydroxy organic acid is selected from tartaric acid, citric acid, malic acid, mandelic acid, and lactic acid. The predominant biological optical isomers are preferred. The 2-hydroxy organic acid can also be provided as the racemate, as well as any of its optically pure isomers. In some embodiments, the (+) enantiomer is preferred (e.g., L-lactic acid, L(+)-Lactic acid).
As used herein, the term “sanitize” or “disinfect” shall mean the reduction of viable microorganisms on surfaces with the exception of bacterial endospores. In some embodiments, the reduction is by at least 99.9%, 99.99%, 99.999% (e.g., by 3, 4, or 5 log units, respectively) or at least by 3, 4, 5, 6, 7, 8, or log units as measured before and after contact with the sanitizing solutions according to the invention. In some embodiments, the sanitized surfaces have levels of pathogenic microorganisms considered safe according to any applicable public health ordinance or below thresholds thought to pose risk of infection or disease. Accordingly, a surface need not have complete elimination or destruction of all forms of microbial life to be sanitized. The reduction may be by physical removal, or toxicity to the microorganism leading to the destruction or inhibition of the growth of the microorganism.
The term “item” refers to something material and is tangible. “Items” include surfaces. These surfaces can be hard surfaces (glass, ceramic, metal, rock, wood, and polymer surfaces), soft surfaces (e.g., elastomeric or plastic surfaces, fabric surfaces).
Accordingly, surfaces may belong to woven or non-woven materials. The term “item” embraces surfaces and the article to which the surface belongs. A surface can belong to any instrument, device, apparatus, tool, cart, furniture, structure, or building. Accordingly, surfaces include the surfaces of floors, walls, ceilings, or fixtures of structures in which the activity occurs.
In some embodiments, the surfaces are employed in domestic and commercial food processing and food preparation activities and/or environments. A surface can be that of an uncooked or raw food item (e.g., meat, fish, poultry, produce) or a packaged food item. Such surfaces also include, but is not limited to, any surface of a tool, machine, equipment, container, packaging, garment (e.g., glove, boot), structure, building, or the like that is used or found in a food harvesting, transport, processing, preparation, or storage activity. Examples of such surfaces include, but are not limited to, the surfaces of slicing, canning, or transport equipment used in processing food; the surfaces of utensils, dishware, wash ware, containers, used in processing or holding foods,), and of building surfaces (e.g., floors, walls, ceilings) or building fixtures present in the food processing environment.
Food processing surfaces can also be found in many applications in the food industry and agriculture. These applications include food anti-spoilage systems. These systems include air circulation systems, cooling towers, beverage chillers and warmers, food refrigeration and cooler cleaners and sanitizers, food packaging materials, cutting board additives, ware washing sanitizing, third-sink sanitizing, meat chilling or scalding waters, aseptic packaging sanitizing, blancher cleaning and sanitizing, food processing antimicrobial garment sprays, and rinse additives.
Items include the surfaces of items found in the agriculture and veterinary environments and activities. Suitable items or surfaces include, but are not limited to, animal feeds, animal watering stations and enclosures, animal quarters, animal veterinarian clinics (e.g. surgical or treatment areas), and animal surgical areas. Accordingly, items include, but are not limited to, foods and their surfaces. Such items include any substance, usually composed of carbohydrates, fats, proteins and water, that can be eaten or drunk by an animal, including humans, for nutrition or pleasure. Items considered food may be obtained from plants, animals, fungus, and fermentation (e.g., ethanol). A food may be edible with or without further preparation. Foods include produce, processed fruit or vegetables, meat products, meat (e.g. red meat and pork), seafood, poultry, fruits and vegetables, eggs, living eggs, egg products, ready to eat food, wheat, grains, seeds, roots, tubers, leaves, stems, corms, flowers, sprouts, herbs, seasonings, or a combination thereof. Foods also include animal feeds.
In some embodiments, the item is a plant material. The phrase “plant material” includes any plant substance or plant-derived substance, including growing plants. Plant materials include seeds, nuts, nut meats, cut flowers, plants or crops grown or stored in a greenhouse, house plants. Plants may be edible or inedible.
In some embodiments, the food is a processed fruit or vegetable. A “processed fruit or vegetable” references a fruit or vegetable that has been cut, chopped, homogenized, sliced, peeled, ground, milled, frozen, cooked (e.g., blanched, pasteurized), or irradiated.
In some embodiments, the food is produce. The term “produce” refers to plant derived foods including fruits and vegetables and the edible portions of other plants (e.g., seeds, nuts, herbs) which may typically be eaten raw or uncooked. Produce, includes, but is not limited to, whole or cut organic and non-organic vegetables and fruits, including but not limited to those which are eaten uncooked. In some embodiments, the produce is Spring Mix, spinach, Romaine lettuce, avocado, yam, asparagus, escarole, arugula, radicchio, pea shoots, dill, chives, head lettuce, leaf lettuce (e.g., red and green lettuce), Iceberg lettuce, endive, parsley, spinach, radishes, celery, carrots, beets, onions, rhubarb, eggplant, peppers, pumpkins, zucchini, cucumbers, tomatoes, potatoes, sweet potatoes, turnips, rutabagas, zucchini, cabbage (e.g., red and green cabbage), kale (e.g., green and purple kale), kohlrabi, collard greens, cauliflower, oriental vegetables (e.g., baby bakchoy, string beans, mustard plant, Chinese broccoli, napa cabbage, chives, cilantro, yau-choy, loofah), Brussels sprouts, okra, mushrooms, snow pea, soybean, broccoli, snapdragon pea, corn, and dandelion greens; fruits such as apples, pineapple, melons (e.g., cantaloupe, watermelon, honeydew, muskmelon, winter melon), citrus fruit (e.g., orange, lemon, tangerine, grapefruit), golgi, acai, peaches, cherries, apricots, persimmons, kiwi, quince, plums, prunes, grapes, and pears; and berries such as strawberries, raspberries, gooseberries, loganberries, boysenberries, cranberries, currants, elderberries, blackberries, and blueberries. In some embodiments, the produce is whole or cut banana, mango, papaya, herb, cilantro, bell pepper, onion, pineapple. In some embodiments, the composition according to the invention is applied to a whole banana to prevent spoilage (e.g, crown rot).
In some embodiments, the item is a meat product. The phrase “meat products” references all animal portions comprising the edible parts of an animal, including muscle, fat, organs, and skin. The source animal may be a mammal, bird, fish, reptile, amphibian, snail, clam, or crustacean. The term includes seafood (e.g. lobster, crab). A meat product may comprise the whole or part of the animal carcass. Meat products include cured meats, sectioned and formed products, minced products, finely chopped products, ground meat and products containing such. Meat products include, but are not limited to poultry, beef, pork, and lamb meat products.
In some embodiments, the outer skin of the carcass of a cattle, sheep, chicken, duck or other poultry, or pig is sanitized by contacting or treating the surface with a composition according to the invention.
Accordingly, in some embodiments, the food item is poultry. “Poultry” refers to all forms of any bird kept, harvested, or domesticated for meat or eggs, and including, but not limited to, chicken, turkey, ostrich, game hen, squab, guinea fowl, pheasant, quail, duck, goose, emu, or the like and the eggs of these birds. Poultry includes whole, sectioned, processed, cooked or raw poultry, and encompasses all forms of poultry flesh, by-products, and side products. The flesh of poultry includes muscle, fat, organs, skin, bones and body fluids and like components that form the animal. Forms of animal flesh include, for example, the whole or part of animal flesh, alone or in combination with other ingredients. Typical forms include, for example, processed poultry meat, such as cured poultry meat, sectioned and formed products, minced products, finely chopped products and whole products
In some embodiments, the item is a food processing surface. A “food processing surface” refers to any surface of a tool (e.g., knife, blade), machine, equipment, container, packaging, garment (e.g., glove, boot), structure, building, or the like that is used or found in a food harvesting, transport, processing, preparation, or storage activity. Examples of such surfaces include, but are not limited to the surfaces of slicing, canning, or transport equipment used in processing food; the surfaces of utensils, dishware, wash ware, containers, used in processing or holding foods), and of building surfaces (e.g., floors, walls, ceilings) or building fixtures present in the food processing environment. Food processing surfaces and environments to be sanitized can also be aseptic packaging, food refrigeration and cooler cleaners, ware washing, food anti-spoilage air circulation systems, blanchers, food packaging materials, cutting board additives, third-sinks, beverage chillers and warmers, meat chilling or scalding waters, cooling towers, and non-to-low-aqueous food preparation lubricants, oils, and rinse additives.
In some embodiments, the item is a wash water or a food processing water. The term “food processing waters” includes any water medium used in the transport, processing, and/or washing of foods and food products. Food process or transport waters include produce transport waters (e.g., as found in flumes, pipe transports, cutters, slicers, blanchers, retort systems, washers, and the like), belt sprays for food transport lines, boot and hand-wash dip-pans, third-sink rinse waters, and the like.
In some embodiments, the item to be treated is a recycled water. A sufficient quantity of the composition according to the invention can be added or used to provide an effective antimicrobial action even after a certain amount is consumed by the organic burden or microbes already present. The recycled water can also be strained, filtered, diluted, or otherwise cleaned during recycling. Levels of the peroxyacetic acid and lactic acid can be monitored to assure an adequate concentration is maintained in a recycled water. Accordingly, a concentrate of a composition according to the invention may be added to the recycled water to maintain a concentration of peroxyacetic acid and the 2-hydroxyorganic acid as set forth herein for the compositions according to the invention.
“Agricultural” items or surfaces include, but are not limited to, “veterinary” items or surfaces include, which include animal feeds, animal watering stations and enclosures, animal quarters (e.g., pens, cages and corrals), animal veterinarian clinics (e.g. surgical or treatment areas), animal research facilities, and animal surgical areas, and the like.
The term “essentially free” means that the referenced compound or substance is present in the solution at a level less than about 300, preferably less than about 150 and more preferably less than about 50 and most preferably less than about 10 ppm or even 1 ppm by weight.
Accordingly, in a first aspect, the invention provides an aqueous solution or gel comprising 1) an organic peracid of the formula RC(O)OOH wherein R is methyl, ethyl, n-propyl, or s-propyl; ii) a 2-hydroxy organic acid selected from tartaric acid, citric acid, malic acid, mandelic acid, and lactic acid; iii) water; and optionally, iv) an anionic surfactant, wherein the aqueous solution has a pH from 2.5 to 6.0. In some embodiments, the pH is from 2.5 to 3.5, 2.5 to 4.0, 2.7 to 3.5, 2.5 to 5.0, 3.0 to 4.0, 3.0 to 5.0, 3.0 to 6.0, or from 3.5 to 4.5. A composition according to the invention may optionally contain other antimicrobial ingredients or be essentially free or substantially free of other antimicrobial ingredients.
Suitable 2-hydroxy organic acids for use in the aqueous solutions of the invention are tartaric acid, citric acid, malic acid, mandelic acid, and lactic acid (i.e., 2-hydroxypropanoic acid). An exemplary 2-hydroxy organic acid is lactic acid. A combination of two or more of any of the above 2-hydroxy organic acids may be used (e.g., lactic acid+citric acid; lactic acid+tartaric acid; lactic acid+malic acid; lactic acid+mandelic acid;).
A sanitizing composition according to the invention accordingly comprises i) an organic peracid of the formula RC(O)OOH wherein R is methyl, ethyl, n-propyl, or s-propyl; ii) a 2-hydroxy organic acid selected from tartaric acid, citric acid, malic acid, mandelic acid, and lactic acid; iii) water and a pH from 2.5 to 7.8, inclusive, wherein the concentration of peracid is from 40 to 250 ppm (w/w) inclusive, and the concentration of the 2-hydroxy organic acid is from 0.1 to 1% (w/w), inclusive. In further embodiments of any of the above, the principal component by weight of the composition is water. In some embodiments, the composition according to the invention is at least 50%, 60%, 70%, 80%, 90%, 95%, 98% or 99% water by weight.
In some embodiments, the peracid is peroxyacetic acid, the organic acid is lactic acid, and the anionic surfactant is sodium lauryl sulfate. In other embodiments, the concentration of peracid acid in the composition is from 3 to 100 ppm (w/w), the concentration of 2-hydroxy organic acid in the solution is from 0.1% to 2% (w/w); and the pH is between 2.5 and 5.0. In a still further embodiment, the concentration of peracid is 5 to 100 ppm (w/w), the concentration of 2-hydroxy organic acid is 0.1 to 2% (w/w).
In an additional embodiment, the aqueous composition of the invention, has a concentration of peracid in the composition is from about 60 to 80 ppm (w/w), a concentration of 2-hydroxy organic acid in the solution of from about 0.2% to 1.25% (w/w); and a pH between about 2.8 to 4.2 or 3.8 and 4.2, inclusive.
In some embodiments, the concentration of the peracid in the composition can be from 3 to 100 ppm (w/w), the concentration of 2-hydroxy organic acid in the composition can be from 0.1% to 2% (w/w); and the pH is between 2.5 and 5.0. In a still further embodiment, the concentration of peracid is 50 to 100 ppm (w/w) and the concentration of 2-hydroxy organic acid is 0.1 to 1% (w/w). In further embodiments, the peracid is peroxyacetic acid and the 2-hydroxy organic acid is lactic acid (e.g., L(+)-lactic acid). In still further embodiments, the concentration of the peracetic acid is 60 to 90 ppm or 70 to 80 ppm. In still further embodiments of such, the concentration of the lactic acid is 0.1 to 0.8% or 0.2 to 0.4% (w/w).
In a particularly preferred embodiment, the invention provides a composition comprising, or consisting essentially of, an aqueous composition of peroxyacetic acid and lactic acid (e.g., L-(+)-Lactic acid) at a pH of from about 2.5 to 6.0, and more preferably at a pH between 2.8 to 4.2 or 3.8 to 4.2, inclusive, wherein an amount of the composition further comprises hydrogen peroxide and acetic acid and the composition is substantially free of any surfactant.
In some embodiments, the aqueous solution is substantially free of any isomer of lactic acid other than L-(+)-Lactic acid. In further embodiments of any of the above, the concentration of peracid (e.g., peroxyacetic acid) in the composition is from 30 to 300 ppm (w/w), 60 to 80 ppm (w/w), 50 to 200 ppm (w/w); 60 to 160 ppm (w/w), 120 to 160 ppm (w/w), or 140 to 160 ppm (w/w); and the concentration of 2-hydroxy-organic acid (e.g., lactic acid) in the solution is selected from 0.1% to 5% (w/w), 0.1% to 2%, 0.2% to 1%, 0.2% to 0.6%, or 0.1% to 0.5%, or about 2%, 3%, or 4%; and the pH is from between 2.5 and 6.0, 2.5 to 5.0, 2.8 and 3.2, 2.5 and 3.5, or 2.6 and 3.2. In other embodiments of the above the solution is for contacting the item to be sanitized from 10, 20 or 30 seconds to 2 minutes or about 10, 20, 30 or 40 secs. In further embodiments, the concentration of peracid acid is from 30 to 100 ppm (w/w), and the concentration of the 2-hydroxy organic acid is from 0.3 to 2.0% (w/w). In a particularly preferred embodiment, the concentration of peracid is 70 to 80 ppm (w/w), and the concentration of the 2-hydroxy organic acid is from 0.2 to 0.4% (w/w). In other embodiments of any of the above, the composition is at a temperature of 35° F. to 45° F. or at ambient temperature. These aqueous compositions can be free or substantially free of surfactants including any or all of nonionic surfactants, cationic surfactants or anionic surfactants. Generally, low levels of hydrogen peroxide from 1 to 20 ppm, 5 to 15 ppm, or 7 to 12 ppm may be present in the composition. In some embodiments, any peracid of the 2-hydroxy organic acid formed from hydrogen peroxide or present in the aqueous composition can be present in an amount which is less than 1/10th, ⅕th, 1/20th, or 1/50th the amount of the corresponding 2-hydroxyorganic acid in the solution. In preferred embodiment of the above, the peracid is peroxyacetic acid and the 2-hydroxyorganic acid is selected from one or more of tartaric acid, citric acid, malic acid, mandelic acid, and lactic acid. In a particularly preferred embodiment, of any of the above, the 2-hydroxy organic acid is lactic acid.
A catalyst, added to accelerate the rate at which the organic peracid reaches equilibrium, may optionally also be present in the composition according to the invention. Typical catalysts are strong acids, such as, sulfuric acid, sulfonic acids, phosphoric, and phosphonic acids. When the peracid composition is diluted to produce the desired peracid level, the catalyst may also be diluted. The presence of low levels of sulfuric acid, for example concentrations in the range of about 1 ppm to about 50 ppm, does not adversely affect the properties of the sanitizer composition.
Optionally, any of the solutions of the invention may further comprise an agent to reduce or suppress sudsing or foaming of the composition during use or contact with the item. The composition according to the invention may also be essentially free of any nonionic, anionic, and/or cationic surfactant and/or also be essentially free of any thickening agent.
The compositions according to the invention may also comprise a colorant to facilitate detection of the solution on the item.
If anionic surfactants are to be added to the aqueous compositions of the invention they are preferably selected from food-safe materials known in the art, C6-18 alkyl sulfates and/or sulfonates (e.g., sodium or potassium lauryl sulfate) and mixtures thereof. The alkyl sulfates are preferred, for antimicrobial effectiveness and palatability, especially as the sodium and/or potassium salts. Sodium dodecyl sulfate, or sodium lauryl sulfate, is a particularly preferred anionic surfactant.
In some embodiments, the composition comprises an amine oxide at a mole ratio of amine oxide to peroxycarboxylic acid of 1 or more. Many peroxycarboxylic acid composition exhibit a sharp, annoying, or otherwise unacceptable odor. Such an unacceptable odor can be reduced by adding an amine oxide to the peroxycarboxylic acid. The peroxycarboxylic acid can be made in the presence of the amine oxide, or the amine oxide can be added after forming the peroxycarboxylic acid. In an embodiment, the amine oxide can be employed in food products or for cleaning or sanitizing food processing equipment or materials. In an embodiment, the amine oxide can be employed in a health-care environment. In an embodiment, the amine oxide is non-toxic. In an embodiment, the amine oxide can be employed according to guidelines from government agencies, such as the Food and Drug Administration, without adverse labeling requirements, such as labeling with a skull and cross bones or the like. Preferred amine oxides include octyl amine oxide (e.g., octyldimethylamine oxide), lauryldimethyl amine oxide, and the like. Alternatively, the amine oxide can be applied separately to an item previously treated with a composition of the invention. In such embodiments, the amine oxide is preferably in an aqueous solution.
The amine oxide is typically present in a quantity that effectively reduces odor of the peroxycarboxylic acid. Suitable levels of amine oxide include a mole ratio of amine oxide to peroxycarboxylic acid of 1 or more. In an embodiment, the mole ratio is greater than or equal to 2. In an embodiment, the mole ratio is greater than or equal to 3. In an embodiment, the mole ratio is 2 to 5. In an embodiment, the mole ratio is 3 to 5. Octyl dimethyl amine oxide has a molecular weight of about 3 (e.g. 2.7) times as great as peroxyacetic acid, and applicable weight ratios can be calculated on such a basis (see, U.S. Pat. No. 7,622,606, issued Nov. 24, 2009, which is incorporated by reference with respect to suitable amine oxides for this purpose).
Exemplary amine oxides are of the formula
wherein R1, R2, and R3 are independently selected from saturated or unsaturated and straight or branched alkyl groups having from 1-18 carbons and aromatic groups, etc. and which can optionally contain O, N or P as a heteroatom or polyalkoxy groups. Examples of amine oxides include, but are not limited to: alkyldimethylamine oxide, dialkylmethylamine oxide, alkyldialkoxyamine oxide, dialkylalkoxyamine oxide, dialkyletheramine oxide and dialkoxyetheramine oxide. In an embodiment, R1 is an alkyl group having 4-18 carbons and R2 and R3 are alkyl groups having 1-18 carbons. In an embodiment, R1 is an alkyl group having 6-10 carbons and R2 and R3 are alkyl groups having 1-2 carbons. In an embodiment, R1 is an alkyl group having 8 carbons (an octyl group) and R2 and R3 are alkyl groups having 1-2 carbons. In an embodiment, R1 is an alkyl group having 12 carbons (a lauryl group) and R2 and R3 are alkyl groups having 1-2 carbons. In some embodiments, the amine oxide is octyldimethylamine oxide, myristyldimethylamine oxide, didecylmethylamine oxide, methylmorpholine oxide, tetradecyldiethoxyamine oxide, or lauryldimethylamine oxide.
In some embodiments, accordingly, the peracid is peroxyacetic acid, the organic acid is lactic acid, and the anionic surfactant is sodium lauryl sulfate. In other embodiments, the concentration of peracid acid in the composition is from 3 to 100 ppm (w/w), the concentration of 2-hydroxy organic acid in the composition is from 0.1% to 2% (w/w); and the concentration of the anionic surfactant in the composition is from 10 to 2500 ppm, and the pH is between 2.5 and 5.0. In a still further embodiment, the concentration of peracid is 5 to 100 ppm (w/w), the concentration of 2-hydroxy organic acid is 0.1 to 2% (w/w), and the concentration of anionic surfactant is 50 to 400 ppm.
Generally, the concentration of hydrogen peroxide in the aqueous composition is 5-fold to 10-fold less that the concentration of the peracid and its presence may reflect the equibilibrium or interconversion of the peracid with the corresponding acid and hydrogen peroxide. The concentration of the hydrogen peroxide can be for instance less than 5 ppm, 10 ppm or 20 ppm depending upon the selection and concentration of the peracid. Accordingly, the concentration of hydrogen peroxide in the aqueous composition is typically much less than that of the peracid.
Accordingly, in some embodiments, the invention provides an aqueous composition comprising i) an organic peracid of the formula RC(O)OOH wherein R is methyl, ethyl, n-propyl, or s-propyl; ii) a 2-hydroxy organic acid selected from tartaric acid, citric acid, malic acid, mandelic acid, and lactic acid; and, optionally, iii) an anionic surfactant; wherein the aqueous solution has a pH from 2.5 to 6.0, 4.0 to 6.0, 3.5 to 4.5, 3.0 to 5.0, 3.6 to 4.2, from 2.5 to 5.0, 2.5 to 4.5, 2.5 to 3.5, 2.7 to 3.5, 3.6 to 4.6, 2.8 to 3.2, inclusive, or about 3.0 (e.g., 3.0+/−0.2; 3.0+/−0.3); and the concentration of peracid is from 40 to 250 ppm (w/w) inclusive, and the concentration of the 2-hydroxy organic acid is from 0.1 to 1% (w/w), inclusive. In further embodiments, the aqueous composition has a peracid which is peroxyacetic acid and a 2-hydroxy organic acid which is is L-(+)-lactic acid. In still further embodiments, the concentration of the peroxyacetic acid in the composition is from 50 to 100 ppm (w/w), the concentration of the lactic acid in the solution is from 0.1% to 0.6% (w/w). A preferred aqueous composition has a concentration of peroxyacetic acid from 60 to 80 ppm (w/w) and a concentration of lactic acid of from 0.1% to 0.4% (w/w). In other embodiments of any of the above the pH falls in a range selected from 2.5 to 4.5, 2.8 to 3.2, 2.5 to 5.0, and 2.7 to 3.5. In other embodiments of any of the above, the composition is at a temperature of 35° F. to 45° F. or at ambient temperature. These aqueous compositions can be substantially free of surfactants including any or all of nonionic surfactants, cationic surfactants or anionic surfactants. Generally, low levels of hydrogen peroxide from 1 to 20 ppm, 5 to 15 ppm, or 7 to 12 ppm may be present in the composition. Any peroxy 2-hydroxy organic acid formed or present in the aqueous composition can be present in an amount which is less than 1/10th, ⅕th, 1/20th, or 1/50th the amount of the corresponding 2-hydroxyorganic acid in the solution.
In some embodiments, the aqueous composition is formed by adding a solution of the 2-hydroxy organic acid which is substantially free of hydrogen peroxide to a solution of the peracid or by adding a solution of the peracid to a solution of the 2-hydroxy organic acid which is substantially free of hydrogen peroxide. The resulting mixture can be a concentrate or pre-blend as described above or in a sanitizing concentration suitable for contacting with an item as described herein. In other embodiments, the organic acid which is substantially free of any hydrogen peroxide and the peracid are added separately to an aqueous fluid used to wash or sanitize the item. In some embodiments, the pH and/or the concentration of the peracid and/or the concentration of the 2-hydroxy organic acid in the composition as used is maintained by monitoring one or more of the pH, concentration of the peracid, concentration of the 2-hydroxy organic acid, or oxidation reduction potential of the composition and adding a concentrate or pre-blend of the aqueous solution to maintain the pH, the concentration of the peracid and lactic acid in the aqueous solution during use of the composition in contacting the item.
Any of the above compositions of the invention may in particular further comprise an agent to reduce or suppress sudsing or foaming of the solution during use or contact with the item. The solutions according to the invention may also be essentially free of any nonionic and/or cationic surfactant and/or also be essentially free of any thickening agent.
In an additional embodiment, the aqueous composition of the invention has a concentration of peracid in the composition from about 60 to 80 ppm (w/w), a concentration of 2-hydroxy organic acid in the composition of from about 0.2% to 1.25% (w/w); and a concentration of anionic surfactant in the composition of from about 150 to 200 ppm (w/w), and a pH between about 3.8 and 4.2, inclusive or 3.8 and 4.2, inclusive.
The aqueous compositions according to the invention may also optionally include a sequestering agent that chelates metals that catalyze the decomposition of hydrogen peroxide. These agents include, but are not limited to, organic phosphonic acids capable of sequestering bivalent metal cations, as well as the water-soluble salts of such acids. A common chelant is 1-hydroxyethylidene-1,1-diphosphonic acid. The chelants present in the sanitizer composition are typically diluted upon use, thus minimizing their effect during use. In particular, an aqueous sanitizer composition of the invention can optionally contain an agent to chelate magnesium or calcium.
Without being wed to theory, the presence of the optional anionic surfactant may serve to reduce the surface tension and viscosity of the aqueous composition and facilitate the spread of the solution over the surface of the item. The low viscosity improves the completeness of the treatment by promoting spreading over the surface of the food, especially where there are layers, rugosities, etc. The low viscosity also improves rinsing properties and the speed of any residual drying.
In some embodiments, the aqueous composition is capable of reducing a microbial contamination on the surface of the item (e.g., produce) by at least 2 log units, more preferably, by at least 3 log units, and still more preferably by at least 4, log units according to any method as described in the Examples (e.g., using E. Coli or Listeria pathogen surrogates attached to lettuce leaves). In other embodiments, the method inhibits spoilage or prolongs shelf-life of a food item by 10%, 20%, 30, 40%, 20 to 50% or by 1, 2, 3, 4, or 5 days according to any method as described in the Examples.
The compositions may be provided as a pre-blend or concentrate which is diluted with water to achieve a sanitizing solution for contacting with an item as described herein. Pre-blends or concentrates are contemplated which require a 4- to 200-fold, 10 to 100-fold, 10 to 50-fold, 10 to 25 fold, 4 to 10-fold dilution with water before use (e.g., about a 5-, 10-, 20- 40-, 50, 100-fold dilution).
The term “substantially free” generally means the referenced substance is absent or present as a minor constituent which may not materially change the properties of the referenced material. With respect to hydrogen peroxide, a 2-hydroxy organic acid solution which is substantially free of hydrogen peroxide can be one which has no hydrogen peroxide or else has an amount of hydrogen peroxide which is less than 0.1 ppm (w/w). With respect to a peroxy 2-hydroxyorganic acid, a sanitizing solution is substantially free of the 2-hydroxy organic peracid if the 2-hydroxy organic peracid is absent in a referenced composition or is present in an amount which is less than 1/10th, 1/20th, 1/40th or 1/100th of that of the corresponding 2-hydroxy organic acid or is present only as a reaction product first formed by a reaction of the 2-hydroxy organic acid in solution containing hydrogen peroxide and an organic peracid of the formula RC(O)OOH wherein R is methyl, ethyl, n-propyl, or s-propyl. Accordingly, in some embodiments, the sanitizing composition or 2-hydroxy organic acid solution used in the making of the sanitizing composition is substantially free of a peracid of the 2-hydroxy organic acid.
The disinfectant or sanitizing compositions of the present invention can be in a variety of forms including solutions, suspensions, gels, foams, fogs, sprays and wipes. Additional types of products include disinfectant foams, creams, mousses, and the like, and compositions containing organic and inorganic filler materials, such as emulsions, lotions, creams, pastes, and the like. The disinfectant compositions can also be used as disinfectant fogs and disinfectant mists. The present compositions can be manufactured as dilute ready-to-use compositions, or as concentrates that can be diluted prior to use. The various compositions may also include fragrances, depending on the nature of the product. For example, a pine or lemon fragrance may be desirable for use for kitchen cleaning wipes because of their appealing association with cleanliness to many consumers. Further, gels or aerosols may also be fragranced for similar or other reasons. In some embodiments, the principal component by weight of the composition is water. In some embodiments, the composition according to the invention is at least 50%, 60%, 70%, 80%, 90%, 95%, 98% or 99% water by weight.
In one embodiment of the present invention, the disinfectant compositions are used to make disinfectant wipes. The disinfectant wipes of the present invention can be used to clean a variety of hard and other surfaces, including human hands and skin, medical instruments, countertops, sinks, floors, walls, windows, etc. The wipes of the present invention can be made of a variety of fabrics. For the purposes of the present invention, fabrics can include cloths and papers, as well as woven and non-woven materials. The woven or nonwoven fabrics can be made of suitable materials such as rayon, nylon, or cotton, linen, combinations thereof. Examples of nonwoven fabrics are described in U.S. Pat. Nos. 3,786,615; 4,395,454; and 4,199,322; which are hereby incorporated by reference. The fabrics or papers can be impregnated with a disinfectant solution by any method known in the art. The wipes can be packaged individually or in any manner known in the art including individual blister-packs or wrapped or stacked multi-packs.
In another embodiment, the disinfectant composition of the present invention is formulated into a gel or gelatinous sanitization composition. In addition to the disinfectant compositions, the gel sanitizers of the present invention can include a thickening or gelling agent, wherein “thickening agent” and “gelling agent” are used interchangeably. For the purposes of the present invention, the terms “gel” or “gelatinous” sanitization compositions refers to a disinfectant liquid substances that can have a viscosity from about 1,000 centipoise to about 100,000 centipoise, or from 2,000 centipoise to 50,000 centipoise in another embodiment, though these ranges are not intended to be limiting. A hand gel may be considerably less viscous than a gel used for industrial cleaning or disinfectant purposes. Examples of gelling or thickening agents include but are not limited to natural gum such as guar and guar derivatives, a clay, fumed silica, a synthetic polymer, a carbomer, cellulose, a cellulose derivative, algin, an algin derivative, a water-insoluble C8-C20 alcohol, an acrylate homopolymer, an acrylate copolymer, carrageenan, an oil, a wax, aloe vera gel, mixtures thereof, and the like. The gelling agent can be present in the gelatinous sanitation composition in an amount from about 0.1 wt % to 50 wt % of the gelatinous composition. In another embodiment, the gelling agent is present in an amount from 0.25 wt % to 10 wt % of the gelatinous composition. The amount of gelling agent can be dependent on a variety of factors including the desired viscosity and the gelling agent. The gelatinous sanitizers find a variety of applications. In one particular embodiment, the disinfectant composition can be combined with natural aloe gel to form a disinfectant aloe formulation. Such formulations find use where skin contact may occur or is intended.
In another embodiment, the disinfectant composition of the present invention can be provided as a disinfectant foam or foaming composition. The disinfectant foams or foaming compositions include a disinfectant or sanitizing composition according to the invention and foaming agents. Any foaming agent known in the art can be used depending on the desired application and characteristics of the resulting disinfectant foam.
In another embodiment, the disinfectant or sanitizing composition of the present invention can be in the form of a aerosol or fog. Fogging is a means by which disinfectants are aerosolized. The aerosol particles of the disinfectant may be suspended within the air for a period of time in order to disinfect both the air itself and surfaces, including inaccessible surfaces or portions of a structure such as the interior surfaces of air vents. The aerosolized particles of disinfectant may have a particle size of from about 5 micrometers to about 200 micrometers. In another embodiment, the aerosolized particle may have a particle size of from about 20 micrometers to about micrometers.
Fogging is particularly useful in disease prevention and control. Fogging machines typically work by using high volumes of air under great pressure to generate small droplets. The disinfectants compositions of the present invention are compatible with most standard fogging machines. Examples of suitable fogging machines include Dyna-Fog's®. Thermal Foggers and Cold Foggers.
As a solution, the sanitizing composition according to the invention can be used as a liquid dispersion bath for objects such as instruments or as a spray for applying to less mobile objects.
In some embodiments, the invention provides a kit comprising the aqueous sanitizing solution according to the invention and instructions for its use in the treatment of fomites or other items as described above. In some further embodiments, the kit provides a first part comprising a peracid solution that is at or near equilibrium. Typically the solution is provided ready to use or else comprises about 5% to about 35% by weight of a peracid, such as peroxyacetic acid, or mixture of peracids and comes with instructions as to how much it should be diluted with water prior to use. The kit optionally contains a soaking bowl and strainer. The ready-to-use formulation may be provided in a spray bottle. In other embodiments, the kit may provide the aqueous sanitizing solution as a concentrate in one container along with a re-Tillable spray bottle optionally containing an amount of the ready-to-use formulation. This kit would include directions as to the appropriate factor of dilution to use when bringing up the concentrate with water. Typically, the concentrate would be 4, 5, 6, 8, 10 or 20-fold more concentrated than the ready to use formulation. Such kits would be especially suitable for consumer use.
In a second aspect, the invention provides a method of sanitizing items, said method comprising contacting the item with an aqueous sanitizing solution according to the invention. The solution can be contacted or applied to the item by any suitable means as known to persons of ordinary skill in the art. For instance, the solution can be applied by any method that insures good contact between the surface to be sanitized and the sanitizer solution. Such methods include bathing, washing, coating, brushing, dipping, immersing, wiping, misting, spraying, and fogging. These steps may be repeated to assure a thorough contacting. Once applied, after a residence time sufficient to assure the desired degree of sanitizing action (e.g., at least 2, 3, 4, 5, 6, 7, or 8 log fold-removal of a microbial contaminant), the solution may be physically removed from the surface of the item by drying, centrifugation and/or draining/and/or rinsing or washing the item with water suitable for use on foods (e.g., potable water). Any combination of these removal steps may be performed in any order. The rinsing is not essential where the peracid, 2-hydroxy organic acid, and sodium lauryl sulfate are present in GRAS amounts. In particular, the peracids preferably used are volatile and, hence, would leave little residue on the item upon drying.
In some embodiments, a plant or produce is treated to prevent rot or spoilage of the item. Accordingly, it is anticipated that the methods described herein will be applicable to preventing or inhibiting a variety of bacterial infections of plants. Pseudomonadaceae, Rhizobiaceae, Enterobacteriaceae, Corynebacteriaceae and Streptomycetaceae bacteria are all economically significant plant pathogens that may be controlled by the present invention. Non-limiting examples of specific plant pathogens that may be effectively inhibited by the methods described herein include: Xanthomonas species, such as, for example, Xanthomonas campestris pv. oryzae; Pseudomonas species, such as, for example, Pseudomonas syringae pv. lachrymans; and Erwinia species, such as, for example, Erwinia amylovora. It is also anticipated that the methods of preventing or inhibiting bacterial infections of plants described herein may also include use together or separately of antimicrobial agents such as bronopol, dichlorophen, nitrapyrin, nickel dimethyldithiocarbamate, kasugamycin, octhilinone, furancarboxylic acid, oxytetracyclin, probenazole, streptomycin, tecloftalam, copper sulphate and other copper preparations which may be formulated separately or together.
Methods of preventing or inhibiting bacterial infections described herein can be used to treat all plants and parts of plants. By plants are understood here all plants and plant populations such as desired and undesired wild plants or crop plants (including naturally occurring crop plants). Crop plants can be plants which can be obtained by conventional breeding and optimization methods or by biotechnological and genetic engineering methods or combinations of these methods, including the transgenic plants and including the plant varieties which can or cannot be protected by varietal property rights. Parts of plants are to be understood as meaning all above-ground and below-ground parts and organs of plants, such as shoot, leaf, flower and root, examples which may be mentioned being leaves, needles, stems, trunks, flowers, fruit-bodies, fruits and seeds and also roots, tubers and rhizomes. Parts of plants also include harvested plants and vegetative and generative propagation material, for example seedlings, tubers, rhizomes, cuttings and seeds.
The treatment of the plants and the parts of plants with the active compounds according to the invention is carried out directly or by action on their surroundings, habitat or storage space, according to customary treatment methods, for example by dipping, spraying, evaporating, atomizing, broadcasting, spreading-on.
In some embodiments, the item is treated to prevent infection or poisoning by a microorganism.
The residence time will vary with the concentration of the peracid (e.g. peroxyacetic acid), the 2-hydroxyorganic acid (e.g., L-(+)-lactic acid, and the surfactant (if any). However, generally, it is contemplated that the surface of the item may be contacted with the aqueous sanitizer solution for a residence time of from about 10 seconds to about 10 minutes. More preferably, the residence time is from about 20 seconds up to about 1, 2 or 4 minutes. The residence time can vary in accordance with the temperature and concentration of the peracid and 2-hydroxyorganic acid. Lower temperatures and concentrations would require longer contact times as could be readily empirically determined by a person of ordinary skill in the art.
The temperature at which the aqueous sanitizer solution/rinse solution is applied should be in accordance with the thermal tolerance of the item. The sanitizer solution can be effectively applied at temperatures suitable for liquid water. Conveniently, the temperature can be ambient or room temperature (e.g., 20° C. to 35° C.). However, other temperatures can be used in accordance with the heat tolerance of the item being treated, the need to use cold temperature to preserve freshness or avoid spoilage of an item, or in accordance with the unadjusted or adjusted temperature of the source water to which the peracid and or 2-hydroxy organic acid is added.
In some embodiments, the contacting reduces a microbial contamination on the surface of the item by at least 3 or 4 log units, more preferably, by at least 5 log units, and still more preferably by at least 6, 7, or 8 log units. The contaminant can be human pathogen (e.g., E. Coli, a strain of E. coli O157H7, Listeria monocyogenes, Salmonella) or an indigenous microorganism typically found on the surface of item.
The aqueous sanitizing solution according to the invention can be used on items in both domestic and commercial applications.
In some embodiments, the microbial contaminant to be reduced by the treatment is a human pathogen (e.g., enterotoxic bacterium), including but not limited to, a bacterium (e.g., E.coli O157H7, Listeria moncytogenes, Salmonella), virus, a fungus, or a mold.
It has also been surprisingly found that the co-formulation of the peracid (e.g., peroxyacetic acid) with the 2-hydroxy organic acid (e.g., L-(+)-lactic acid) in the aqueous sanitizer composition provides a particularly effective and long-lasting sanitizer composition when in use. When in continuous use to treat a plurality of items, the composition has to be refreshed or supplemented with additional peracid and 2-hydroxyorganic acid to maintain a concentration of the peracid in a range of from about 60 to 80 ppm and the lactic acid in a concentration of from 0.2 to 0.4%, or about 2.5%.
In some embodiments, the sanitizing composition is provided as an aqueous pre-blend mixture (e.g., about a 5-200-fold concentrate, a 5-, 10-, 20-, 40-, 50- or 100-fold concentrate) to be added to the water to be contacted with the item. In some embodiments, the concentration of peracid and/or 2-hydroxyorganic acid is adjusted in the wash solution to maintain their concentration(s) by addition of the pre-blend or concentrate based upon the concentration of the peracid and/or 2-hydroxy organic acid in the wash solution as determined by actual measurement or historical consumption data.
In commercial applications, in some embodiments, the item is transported to a sanitizing solution where the item is contacted with the sanitizing solution by immersion in the solution. Air bubbles can be generated to facilitate the contacting and/or the mixing of a pre-blend. The item is then removed from the sanitizing solution, optionally rinsed by spraying with water free of a peracid and 2-hydroxy organic acid/and or by being immersed in water free of a peracid and 2-hydroxy organic acid. The rinse water can be further removed by shaking, centrifuging, air drying, or toweling the item.
The present reduced-odor compositions can be employed for reducing the population of pathogenic microorganisms, such as pathogens of humans, animals, and the like. The reduced-odor compositions can exhibit activity against pathogens including fungi, molds, bacteria, spores, and viruses, for example, parvovirus, coxsackie virus, herpes virus, S. aureus, E. coli, Streplococci, Legionella, mycobacteria, or the like. Such pathogens can cause a varieties of diseases and disorders, including athletes foot, hairy hoof wart disease, mastitis or other mammalian milking diseases, tuberculosis, and the like. In addition, the present compositions can kill pathogenic microorganisms that spread through transfer by water, air, or a surface substrate. A filter containing the composition can reduce the population of microorganisms in air and liquids.
A concentrate or use concentration of a reduced-odor peroxycarboxylic acid composition of the present invention can be applied to or brought into contact with an item by any conventional method or apparatus for applying an antimicrobial or cleaning composition to an object. For example, the object can be wiped with, sprayed with, and/or immersed in the reduced-odor composition, or a use composition made from the reduced-odor composition. Contacting can be manual or by machine.
The present methods require a certain minimal contact time of the composition with the item for occurrence of significant antimicrobial effect. The contact time can vary with concentration of the use composition, method of applying the use composition, temperature of the use composition, amount of a contaminant on the item, number of microorganisms on the item, the environment, the desired degree of sanitizing, and the like. Preferably the exposure time is at least about 5 to about 15 seconds.
In one embodiment, a pressure spray is used to apply a composition according to the invention. During application of the spray composition on the item, the surface of the item can be moved with mechanical action, preferably agitated, rubbed, brushed, etc. Agitation can be by physical scrubbing of the item, through the action of the spray composition under pressure, through sonication, or by other methods. Agitation increases the efficacy of the spray composition in killing micro-organisms, perhaps due to better exposure of the composition into any crevasses or small colonies containing the micro-organisms. The spray composition, before application, can also be cooled to a temperature from 2 to 5° C., 2 to 10° C. for heat intolerant items or heated to a temperature of about 15 to 20° C., preferably about 20 to 60° C. to increase efficacy for a heat tolerant item.
Spray applications can be performed automatically (as in the case of a production line) or manually. Multiple spray heads can be used to ensure complete contact or other spray means. The spray heads can have any useful spray pattern. A spray booth can be used to substantially confines the sprayed composition to within the booth. For instance, a production line item can move through the entryway into the booth where all its exterior surfaces are contacted. After allowing some time for drainage from the surfaces, the item can then exit the booth in a fully treated form. A spray booth can employ steam jets to apply the antimicrobial or sanitizing compositions of the invention. These steam jets can be used in combination with cooling water to ensure that the treatment reaching the item is at the desired temperature and that the item is not undesirably altered (e.g., cooked) by the temperature of the spray.
In some embodiments, the item is immersed into a tank containing a quantity of a composition according to the invention. The composition is preferably agitated to increase the efficacy of the composition and the speed in which the composition reduces micro-organisms accompanying to the poultry product. Agitation can be obtained by conventional methods, including ultrasonics, aeration by bubbling air through the composition, by mechanical methods, stirring, such as strainers, paddles, brushes, pump driven liquid jets, or by combinations of these methods. In some embodiments, the sanitizing composition can be heated to increase the efficacy of the solution in killing micro-organisms.
In another alternative embodiment of the present invention, the item can be treated with a foaming version of the composition according to the invention. The foam can be prepared by mixing foaming surfactants with other ingredients to make a composition according to the invention beforehand or at time of use. The foaming surfactants can be nonionic, anionic or cationic in nature. Examples of useful surfactant types include, but are not limited to the following: amine oxides, alkli sulfates, alkyl ether sulfate, sulfonates, quaternary ammonium compounds, alkyl sarcosines, alcohol ethoxylates, alcohol ethoxylate carboxylate, betaines and alkyl amides. The foaming surfactant is typically mixed at time of use with the sanitizing solution. Use solution levels of the foaming agents is from about 50 ppm to about 2.0 wt-%. At time of use, compressed air can be injected into the mixture, then applied to the item through a foam application device such as a tank foamer or an aspirated wall mounted foamer.
In another embodiment of the present invention, the item can be treated with a thickened or gelled version of the composition which can adhere to the surfaces. The composition or the composition can be thickened or gelled using existing technologies such as: xanthan gum, polymeric thickeners, cellulose thickeners or the like. Rod micelle forming systems such as amine oxides and anionic counter ions could also be used. The thickeners or gel forming agents can be used either in the concentrated product or mixing with the sanitizing solution, at time of use. Typical use levels of thickeners or gel agents range from about 100 ppm to about 0.1 wt-% or from about 0.1 wt-% to 1 wt-%, or from 1 wt-% to 10 wt-%. In the thickened or gelled state the sanitizing solution or gel remains in contact with the item for longer periods of time, thus increasing the antimicrobial efficacy.
The following examples are intended to illustrate, but not limit, the invention.
Example 1. The present example illustrates the use of an aqueous sanitizing solution according to the invention. As illustrated in
This method can be used to determine the shelf life of produce that has been treated by a sanitizing solutions, generally and, particularly, those according to the invention.
Cooled eight 20-gallon containers with 75% water to ˜45° F.
Autoclave twelve 5-gallons tubs wrapped well in tin foil at least 1 day in advance of processing.
Calculations:
Moisture Difference:
Difference=(Mbefire)−(Mafter)
Moisture Percentage:
This procedure is used to determine the antimicrobial activity of sanitizers on microorganisms that are suspended in a liquid.
This method can be used to determine the antimicrobial activity of sanitizers on microorganisms that are attached on the surface of leaves
Processing parameters and treatments
This procedure is used to prepare a 108-109 cfu/mL stock culture for suspended and attached cells challenge tests. The cell concentration of the stock culture is enumerated prior to testing solution.
The effects of a sanitizing solution according to the invention on the removal of microbes on the surface of produce.
The following tables show the results of the suspended-cells challenge tests with and without surfactant:
Listeria Suspended
Listeria Suspended
E. Coli Suspended
Listeria Suspended
The following tables show the results for the attached-cells challenge test:
E. ColiAttached
E. Coli Attached
Listeria Attached
Listeria Attached
The above results accord with a surprisingly effective and striking increase in the removal of microorganisms and improvement of product shelf-life associated due to use of an aqueous solution according to the invention.
Example 2. The next example demonstrates that the presence of a 2-hydroxy organic acid (e.g., lactic acid) greatly reduces the consumption of peroxyacetic acid during the treatment of produce and illustrates the use of an aqueous sanitizing solution according to the invention. As shown below, the solutions according to the invention advantageously conserve peroxyacetic acid during the removal of microorganisms from the surface of a variety of produce. The methods and compositions of the invention are also shown to greatly improve the shelf-life of the produce and greatly retard produce decay. The savings should extend to such diverse microorganisms as bacteria, yeast, and mold.
Synergism with respect to efficacy in a Suspended Cells Challenge Test at 20 s residence time with no surfactant.
The experimental treatment groups were tap water, chlorinated water, a FE sanitizer wash water (FE, FE sanitizer, a solution of peroxyacetic acid and lactic acid, as further specified in a given experiment). The experimental parameters were 40 to 45° F.; the residence time was 20 s; the pH:
The experimental protocol was as follows:
Listeria innocua ATCC 33090
Lactobacillus plantarum 14917
Log reduction of the test FE sanitizer (here, a combination of lactic acid and peroxyacetic acid as specified above) on L. innocua and L. plantarum was significantly better than PA wash water and LA wash water. This clearly indicated the synergistic effects of combining LA and PA. FE sanitizer wash water with 70 ppm PA and 2000 ppm LA at 20 s residence time provided ˜3-log10 reduction on Listeria innocua. The log reduction of provided by the combination of lactic acid and peroxyacetic acid) was about significantly 2 to 4 folds better than peroxyacetic acid with no lactic acid addition.
Example 3. The next experiments compares the effects of sanitizers on vegetative pathogens suspended in a liquid.
Treatments: tap water, chlorinated water, FE sanitizer wash water;
Temperature: 40 to 45° F.; Residence time: 30 s
pH:
Pathogens:
10 ppm chlorinated water reduced the populations of each pathogen by ˜1-log10 when compared to the tap water control. The two concentrations of FE sanitizer wash water plate counts had no residual colonies and the results were recorded as <1.0 log10 cfu/mL. Hence FE sanitizer wash water delivered reductions of greater than 7-log10 for E. coli O157:H7 and Salmonella, and greater than 5.2-log10 for Listeria monocytogenes when compared to the tap water control. The lower reduction observed in Listeria monocytogenes does not indicate that the FE sanitizer was less effective against that pathogen as the reported results were restricted by the original population of the stock inoculum.
Example 4. The purpose of these experiments was to determine the antimicrobial activity of sanitizers on vegetative pathogens that are attached on the surface of leaves
Treatments: tap water, chlorinated water, test FE sanitizer wash water;
Temperature: 40 to 45° F.; Residence time: 30 s;
pH:
Transfer 3L of Test Solution from the PP Carboy into the 5-L Sterile PP Tub
M cfu/g=microbial population on leaves without any treatment;
R cfu/g=microbial population in water solution for the “Water Treatment”;
W cfu/g=microbial population on leaves from “Water Treatment”;
X cfu/g=microbial population on leaves from “X Treatment”;
Hence, Log reduction caused by “Treatment X”=Log (w/x)
Microorganisms removed due to mechanical washing=R
Microorganisms died during the drying process=M-W-R
E. coli O157:H7 on Spinach
E. coli O157:H7 on Romaine
Salmonella on Spinach
Salmonella on Romaine
L. monocytogenes on Spinach
L. monocytogenes on Romaine
The tap water wash removed 0.3 to 1.5 log10 of inoculated cells from the leaves indicating that complete attachment of cells on the leaves was not achieved. This was probably caused by the desiccation and wilting of the leaves under low relative humidity of the environment (20 to 23% rather than 38 to 48% as listed in the protocol).
E. coli O157:H7 on Spinach
E. coli O157:H7 on Romaine
Salmonella on Spinach
Salmonella on Romaine
L. monocytogenes on Spinach
L. monocytogenes on Romaine
The 10 ppm chlorinated water provided an additional reduction of 0.1-log10 to 1.4-log10 on the pathogens. The 2.3-log10 in the case of spinach was exceptionally high when compared with surrogate attached cells results and was probably caused by the incomplete attachment of the cells on the leaves as shown by the tap water wash results.
E. coli O157:H7 on Spinach
E. coli O157:H7 on Romaine
Salmonella on Spinach
Salmonella on Romaine
L. monocytogenes on Spinach
L. monocytogenes on
The test FE sanitizer wash water (69 ppm peroxyacetic acid and 4800 ppm lactic acid) provided an additional reduction of 2.1-log10 to 3.4-log10 on the pathogens when compared with tap water wash.
When compared to chlorinated water, the FE sanitizer provided an additional 2-log10 reduction of pathogens that were attached on leaves. In addition, storing the spread plates at 40F indicated that injured cells were not able to grow at refrigerated temperatures within a week. If the bacterial cells were not able to grown on nutrient rich agar plates, they will most likely not grow on the treated fresh produce.
Example 5. These experiments evaluated the consumption or depletion of peroxyacetic acid when used to wash produce. The objective accordingly was to compare the amount of chopped Romaine Lettuce required to deplete 600 gallons of chlorinated wash water, 600 gallons of peroxyacetic acid wash water, and 600 gallons of FE sanitizer wash water
Treatments: chlorinated water, peroxyacetic acid wash water, and FE sanitizer wash water
Temperature: 38 to 40° F.
Residence time: 20 s
pH:
Produce: 1.5″×2″ diced Romaine lettuce
A. Determination of the amount of Romaine Lettuce that could deplete 600 gallons of peroxyacetic acid wash water.
The depletion of peroxyacetic acid in the FE sanitizer was 5-fold (500%) less than that of the peroxyacetic acid solution with no addition lactic acid. This shows that under the same volume and concentration of peroxyacetic acid, the tested FE sanitizer could disinfect 5 times more produce than the peroxyacetic acid sanitizer with no lactic acid addition. In addition the lbs of free chlorine required to treat a pound of Romaine was 8.5 folds (850%) more than that of the tested FE sanitizer thus indicating that per pound of the tested FE sanitizer could disinfect 8.5 times more produce than per pound of chlorinated water.
The log10 reduction of indigenous microorganism on the Romaine leaf for 73-84 ppm peroxyacetic acid wash water, FE sanitizer wash water (59 to 69 ppm PA and 2,389 to 2,724 ppm LA), and 1.2 to 7.6 ppm free chlorine wash water was 0.7, 2.6, and 1.2-log10, respectively. Although the FE sanitizer in the study was below the optimum lower limit, its log10 reduction on indigenous microorganisms attached on the Romaine leaf was still 2.2 and 3.7 fold, respectively, higher than that of the chlorinated water and peroxyacectic acid wash water.
Example 6. This example focuses on use of the sanitizer on various surfaces.
Inoculum preparation: Pseudomonas aeruginosa (ATCC 9027) freeze dried culture was rehydrated in 10 mL of sterilized nutrient broth (NB) and mixed homogeneously. 0.1 mL of the stock solution was transferred to 10 mL of NB and incubated at 37C for 24 h. Enrichment was streaked to confirm purity. 10 mL of the enriched stock was transferred to 1,000 mL of NB and incubated at 37C for 24 h resulting in ˜108 cfu/mL stationary phase culture stock. The stock was cooled at 4C for 1 h. Microbial population of the stationary phase stock culture was enumerated by means of serial dilution with 9-mL Butterfield phosphate buffer tubes and spread plating on Nutrient Agar (TSA) pre-poured agar plates.
Non-food surface inoculation: The 1000 mL˜108 cfu/mL stock culture solution was homogeneously mixed by shaking and swirling the Erlenmeyer flask. The 1000 mL culture was separated into 20 centrifuge tubes (50 mL each) and centrifuged at 10,000 rpm and 4C for 15 min. The stock culture pellet was re-suspended with 50 mL of NB. All the re-suspended cultures from the 20 centrifuge tubes were combined to form 1,000 mL˜108 cfu/mL inoculating stock culture. 15 mL of the P. aeruginosa inoculating stock together with a non-food surface coupon (2.5 cm×5 cm) were placed in a sterilized 50mL-centrifuge tube and incubated for 24 h at 37C. After 24 hr, the coupon was transferred to a sterile Petri dish and placed in an oven to dry for 1 hour at 35C. The coupons were cut from stainless steel sheet, wood, glass slide, and plastic sheet.
Treatment of inoculated non-food surfaces: 1 mL of test solution was dispensed onto a 2.5cm×2.5 cm marked area of each inoculated coupon for 60 s. A pre-wet sterilized cotton swab was dipped in 10 mL Butterfield phosphate buffer with sodium thiosulfate and swabbed the marked area on the coupon after 60 s exposure. The swabbed was then immediately placed into the 10 mL Butterfield phosphate buffer with sodium thiosulfate and mixed. One mL was immediately transferred from the aforementioned tube to a 9 mL Butterfield phosphate buffer. The total treatment time including the exposure time, the swabbing time, and the transfer time was 90 s. Each solution treatment was performed in duplications. The reduction for each solution treatment was compared to that of the city water treatment.
Inoculum preparation: ATCC freeze dried culture was rehydrated in 10 mL of sterilized tryptic soy broth and mixed homogeneously. 0.1 mL of the stock solution was transferred to 10 mL of TSB and incubated at 37C for 24 h. Enrichment was streaked to confirm purity. 2 mL of the enriched stock was transferred to 200 mL of TSB and incubated at 37C for 24 h and 36 h, respectively for E. coli K-12 (ATCC 25253) (EC) and Listeria innocua (ATCC 33090) (LI) resulting in ˜108 cfu/mL stationary phase culture stock. The stock was cooled for at 4C for 1 h. Microbial population of the stationary phase stock culture was enumerated by means of serial dilution with 9-mL Butterfield phosphate buffer tubes and spread plating on Tryptic Soy Agar (TSA) pre-poured agar plates for EC or Modified Oxford Agar (MOX) pre-poured agar plates for LI.
Vegetable and fruit surface inoculation: The 200 mL˜108 cfu/mL stock culture solution was homogeneously mixed by shaking and swirling the Erlenmeyer flask. The 200 mL culture was separated into 4 centrifuge tubes (50 mL each) and centrifuged at 10,000 rpm and 4C for 15 min. The stock culture pellet was re-suspended with 5 mL of 5% Horse Serum. All the re-suspended cultures from the four centrifuge tubes were combined to form 20 mL˜109 cfu/mL inoculating stock culture. The outer peel or surface of the test vegetable and fruit was cut into 5cm×2.5 cm pieces or diced into 10 cm cubes in the case of tomatoes for inoculation. 50 uL inoculum in the form of 2 uL droplets were spiked onto the strawberry, and diced tomato surface while 100 uL in the form of 2 uL droplets were inoculated onto the potato peel. The spiked surfaces or peels were placed in a biological safety cabinet for 60 min at 18 to 24C for drying.
Treatment of inoculated vegetable and fruit surfaces: Each sample of inoculated vegetable or fruit surface was placed into a 2.5L stomacher bag containing 500 mL of the tested solution and shook vigorously for 45 s. The tested solutions included city water, lactic acid solution (LA), peracetic acid solution (PA), and FreshRinse solution (FR). The treated vegetable or fruit surface was immediately transferred into a sterile stomacher bag containing 100 mL of Butterfield phosphate buffer with 1 sodium thiosulfate pellet at the end of the 45 s treatment. Each solution treatment was performed in duplications. The reduction for each solution treatment was compared to that of the city water treatment.
Inoculum preparation: ATCC freeze dried culture was rehydrated in 10 mL of sterilized TSB and mixed homogeneously. 0.1 mL of the stock solution was transferred to 10 mL of TSB and incubated at 37C for 24 h. Enrichment was streaked to confirm purity. 2 mL of the enriched stock was transferred to 200 mL of TSB and incubated at 37C for 24 h for E. coli K-12 (ATCC 25253) (EC) resulting in ˜108 cfu/mL stationary phase culture stock. The stock was cooled at 4C for 1 h. Microbial population of the stationary phase stock culture was enumerated by means of serial dilution with 9-mL Butterfield phosphate buffer tubes and spread plating on Tryptic Soy Agar (TSA) pre-poured agar plates for EC
Chicken wing surface inoculation: The 200 mL ˜108cfu/mL stock culture solution was homogeneously mixed by shaking and swirling the Erlenmeyer flask. The 200 mL culture was separated into 4 centrifuge tubes (50 mL each) and centrifuged at 10,000 rpm and 4C for 15 min. The stock culture pellet was re-suspended with 5 mL of 5% Horse Serum. All the re-suspended cultures from the four centrifuge tubes were combined to form 20 mL˜109 cfu/mL inoculating stock culture. The chicken middle wing was pat dried by paper towel. A permanent marker was used to mark a 2.5 cm×2.5 cm square at the middle of the flat surface of the chicken wing for inoculation. 50 uL inoculum in the form of 2 uL droplets were spiked onto the marked square on the chicken wing skin. The inoculated chicken wing was placed into a sterile polypropylene basket. The spiked chicken wing inside the polypropylene basket was dried inside a biological safety cabinet for 120 min at 18 to 24C.
Treatment of inoculated chicken wing: Each sample of inoculated chicken wing was placed into a 2.5L stomacher bag containing 500 mL of the tested solution for 10 minutes with intermittent 30 s-shakings at 0, 4, and 9 min. The tested solutions included city water, lactic acid solution (LA), peracetic acid solution (PA), and FreshRinse solution (FR). The treated chicken wing was immediately removed from the treatment solution after 10 min and placed into a sterilized Petri-dish with the marked side facing up. A pre-wet sterilized swab dipped in 10 mL Butterfield phosphate buffer with sodium thiosulfate was used to swab the marked area. After swabbing the cotton wool swab was immediately placed back into the 10 mL Butterfield phosphate buffer with sodium thiosulfate and mixed. One mL was immediately transferred from the aforementioned tube to a 9 mL Butterfield phosphate buffer. The total treatment time including the exposure time, the swabbing time, and the transfer time was 10.5 min. Each solution treatment was performed in duplications. The reduction for each solution treatment was compared to that of the city water treatment
All publications, patents and patent applications cited herein, whether supra or infra, are hereby incorporated by reference in their entirety to the same extent as if each individual publication, patent or patent application was specifically and individually indicated to be incorporated by reference.
| Number | Date | Country | |
|---|---|---|---|
| 61288762 | Dec 2009 | US |
| Number | Date | Country | |
|---|---|---|---|
| Parent | PCT/US2010/000613 | Dec 2010 | US |
| Child | 13528747 | US |
