Claims
- 1. A method of maintaining a controlled level of oxygen within a closed food package, said method comprising:
forming at least one package element having at least container and lid elements from a laminate of polymeric films, said laminate having selected oxygen permeability characteristics to maintain oxygen in said package at a level between the oxygen level which will prevent anaerobic microorganisms from developing and an oxygen level sufficient to permit aerobic bacteria to develop and thus indicate spoilage; placing a food product within the container portion of said package; and closing the package to the outside atmosphere with a removable film disposed over and hermetically sealing said container element.
- 2. The method of claim 1 further comprising:
selecting said laminate polymeric films to maintain a constant partial pressure of oxygen within said closed package at not less than about 1% O2 and not more than about 2% O2.
- 3. The method of claim 1 further wherein:
said closed package has a defined head space; and the volume of said head space is selected in combination with said permeability characteristics of said laminate to maintain at a stable selected level said partial pressure of oxygen within said package.
- 4. The method of claim 1 further comprising:
providing within said container micropores of selected diameter sufficient to permit passage of oxygen therethrough and into said container; and disposing a polymeric label material over said container micropores said polymeric label material having smaller label micropores therein to control diffusion of oxygen therethrough and to maintain partial oxygen pressure within said closed package at a selected level.
- 5. The method of claim 4 wherein said label material comprises expanded polypropylene.
- 6. The method of claim 4 wherein said label material comprises expanded polyethylene.
- 7. The method of claim 1 further comprising:
providing package surface area increasing means upon at least one of container and lid elements for increasing the absolute value of oxygen permeability of the closed package.
- 8. The method of claim 7 wherein said package surface area increasing means comprises ribs disposed upon said package.
- 9. The method of claim 7 further comprising adjusting the size of said package surface area increasing means to control the effective amount of surface area of said package available for oxygen transmission.
- 10. The method of claim 7 further comprising lid providing said package surface area increasing means upon said container element of said food package.
- 11. The method of claim 7 further comprising providing said package surface area increasing means upon said package lid element of said food package.
- 12. The method of claim 7 further comprising:
selecting said laminate polymeric films to maintain a constant partial pressure of oxygen within said closed package at not less than about 1% O2 and not more than about 2% O2.
- 13. The method of claim 7 further wherein:
said closed package has a defined head space; and the volume of said head space is selected in combination with said permeability characteristics of said laminate to maintain at a stable selected level said partial pressure of oxygen within said package.
- 14. The method of claim 7 further comprising:
providing within said container micropores of selected diameter sufficient to permit passage of oxygen therethrough and into said container; and disposing a polymeric label material over said container micropores said polymeric label material having smaller label micropores therein to control diffusion of oxygen therethrough and to maintain partial oxygen pressure within said closed package at a selected level.
- 15. The method of claim 7 wherein said label material comprises expanded polypropylene.
- 16. The method of claim 7 wherein said label material comprises expanded polyethylene.
- 17. The method of claim 4 wherein said container micropores are approximately 25 microns in diameter.
- 18. The method of claim 4 wherein said smaller label micropores are approximately 5 microns in diameter.
- 19. The method of claim 1 wherein at least one package element is formed from styrene-butadiene copolymer.
- 20. The method of claim 1 wherein at least one package element has a gaseous diffusion rate of 400-600 cc O2/24 hours /100 in2/mil at ATM.
- 21. The method of claim 8 wherein said ribs stiffen said package element.
- 22. The method of claim 21 further comprising decreasing the thickness of said package element to control the gaseous permeability characteristics thereof.
- 23. The method of claim 1 wherein said closed food package comprises container and package lid elements with package closure means disposed therebetween.
- 24. The method of claim 23 wherein said package closure element comprises a sealable strip.
- 25. The method of claim 23 wherein said package closure further comprises a flange supporting said sealable strip.
- 26. The method of claim 23 wherein said package closure means comprises mating male and female members.
- 27. The method of claim 23 wherein said package lid element comprises a dome.
- 28. The method of claim 23 wherein said package lid element comprises a dome hermetically sealed with the cup.
- 29. The method of claim 23 wherein said container element includes an opening thereinto and a closure membrane is sealed thereupon.
- 30. A hermetically sealed cup and dome with headspace filled with a mixture of CO2 and N2 or N2 and O2 mixture or Ar/CO2/O2 mixture.
- 31. The method of claim 29 further comprising controlling the gaseous diffusion rate of said closure membrane.
- 32. The method of claim 1 wherein at least one of said package elements has a gaseous diffusion rate of approximately 0.1 cc O2/24 hours /100 ins2/ATM @ 75° F. and relative humidity of 65%
- 33. The method of claim 23 wherein said package container element includes a circumferentially disposed container flange disposed at the top thereof, and said lid element includes a matching lid flange with an outer rim attached thereto to cover said container flange.
- 34. The method of claim 33 wherein the diameter of said outer rim is slightly larger than the diameter of said container flange to remain in place when disposed thereover.
- 35. The method of claim 33 wherein said container flange and said lid flange engage when said lid element is disposed atop said container element.
- 36. The method of claim 33 wherein said lid flange includes an inner rim for firm engagement with said container flange after removal of said removable film.
- 37. The method of claim 33 wherein said container flange and said lid flange engage with sufficient force to prevent hermetic seal rupture during transportation of the package at high altitude or air shipment.
CROSS-REFERENCE TO RELATED APPLICATION
[0001] This application is a continuation-in-part of application Ser. No. ______ [Attorney Docket No. 790077.402], filed on ______.