Process for the preparation of high-temperature short-time sterilized packaged articles

• US 3,892,058 A
• Filed: 09/20/1973
• Issued: 07/01/1975
• Est. Priority Date: 09/22/1972
• Status: Expired due to Term

• Current Assignee: Kanemichi Yamaguchi, Yoshihiro Komatsu
• Original Assignee: Kanemichi Yamaguchi, Yoshihiro Komatsu
• Inventors: Yamaguchi, Kanemichi, Komatsu, Yoshihiro
• Primary Examiner(s): McGehee, Travis S.
• Application Number:
  US05/399,346
• Time in Patent Office: 649 Days
• Field of Search: 53/21FC,22B 21/56 426/407,401,412
• US Class Current: 53/425
• CPC Class Codes: A23L 3/00 Preservation of foods or foodstuffs, in general, e.g. pasteurising, sterilising, specially adapted for foods or foodstuffs preserving foods or foodstuffs in association with packaging B65B55/00
• CPC Class Codes: A23L 3/10 by heating materials in packages which are not progressively transported through the apparatus
• CPC Class Codes: Y10T 428/266 of base or substrate
• CPC Class Codes: Y10T 428/31681 Next to polyester, polyamide or polyimide [e.g., alkyd, glue, or nylon, etc.]
• CPC Class Codes: Y10T 428/31692 Next to addition polymer from unsaturated monomers
• CPC Class Codes: Y10T 428/31739 Nylon type
• CPC Class Codes: Y10T 428/31786 Of polyester [e.g., alkyd, etc.]

Abstract

A process for the preparation of high-temperature shorttime sterilized packaged articles which comprises filling an article to be sterilized in a flexible container having a heat-sealable resin film at least on an area to be heat sealed of the inner surface therof, removing non-condensable gases present in interior voids of the flexible container, hermetically sealing the flexible container by application of heat in such a manner that the coefficient of flatness in the resulting sealed packaged article is maintained at a level not exceeding 0.25, said coefficient of flatness being defined by the following formula

in which l indicates a maximum thickness (cm) in the sealed packaged article, L disignates a maximum distance (cm) across the surface of the container, and KF stands for the coefficient of flatness. MAINTAINING THE SEALED PACKAGED ARTICLE FOR A SHORT TIME IN A HEATING MEDIUM OF A TEMPERATURE EXCEEDING 130*C. to thereby sterilize the article packaged in the container, and cooling the so heat-treated packaged article under a pressure hegher than the saturated vapor pressure corresponding to the sterilization temperature.

Claims

1. A process for the preparation of high-temperature short-time sterilized packaged articles which comprises the steps of providing a flexible container having a heat-sealable resin film at least on an area to be heat sealed of the inner surface thereof with the heat sealable resin being a crystalline thermoplastic resin having a softening or melting point of from 130* to 250* C., filling an article to be sterilized in the flexible container, removing non-condensable gases present in interior voids of the flexible container, hermetically sealing the flexible container by application of heat in such a manner that the coefficient of flatness in the resulting sealed packaged article is maintained at a level not exceeding 0.25, said coefficient of flatness being defined by the following formula

2. A process according to claim 1 wherein when said flexible container is supplied it is assured that said flexible container has two inner surfaces confronting each other and is composed of one or two flexible sheets with said container comprising a space for receiving the article to be sterilized between said two inner surfaces and an area to be heat sealed which is provided around the periphery of said space, and said inner surfaces having at least on said area a film of a heat sealable resin having a softening or melting point of 130* to 250*C.

3. A process according to claim 1 wherein when said flexible container is supplied it is assured that said flexible container is a bag-like container formed by piling two flexible laminate sheets with each sheet including an inner layer of a heat sealable resin having a thickness of 5 to 200 Mu , an intermediate layer of a metal foil having a thickness of 5 to 100 Mu and an outer layer of a heat resistant resin having a thickness of 2 to 100 Mu , so that the heat sealable resin layers confront each other, and providing an area to be heat sealed around a space for receiving the article to be sterilized.

4. A process according to claim 1 wherein when said flexible container is supplied it is assured that said flexible container is a bag-like container formed by piling two flexible laminate sheets with each sheet including an inner layer of a heat sealable resin having 5 to 100 Mu , an intermediate layer of a heat resistant resin having a thickness of 5 to 100 Mu , a layer of a metal foil having a thickness of 2 to 100 Mu and an outer layer of a heat resistant resin having a thickness of 2 to 100 Mu , so that the heat sealable resin layers confront each other, and providing an area to be heat sealed around the periphery of a space for receiving the article to be sterilized.

5. A process according to claim 1 wherein when said flexible container is supplied it is assured that said flexible container comprises a container proper which is formed by press forming a metal foil having a thickness of 25 to 150 Mu and has a space for receiving the article to be sterilized and a flange portion, and a lid compOsed of a metal foil or a laminate of a metal foil and a resin film, a layer of a heat sealable resin being formed between said lid and said flange portion of the container proper.

6. A process according to claim 1 wherein it is assured that the heat sealable resin is poly- omega -aminodecanoic acid.

7. A process according to claim 1 wherein it is assured that the heat sealable resin is polypropylene.

8. A process according to claim 1 wherein it is assured that the heat sealable resin is poly-4-methylpentene-1.

9. A process according to claim 1 wherein it is assured that the heat sealable resin is polytetramethylene terephthalate including a polyalkylene ether structure in the molecular chain.

10. A process according to claim 1 wherein it is assured that the heat resistant resin is biaxially stretched polyethylene terephthalate.

11. A process according to claim 4 wherein it is assured that the intermediate layer-constituting heat resistant resin is biaxially stretched polycapramide.

12. A process according to claim 1 wherein removal of noncondensable gases is accomplished by reducing the pressure in the interior of the container to a level lower by at least 70 cmHg than the atmospheric pressure.

13. A process according to claim 1 wherein removal of non-condensable gases is accomplished by substituting non-condensable gases present in the interior voids of the container by steam.

14. A process according to claim 1 wherein removal of non-condensable gases is accomplished by applying a pressure from the outside to the article-filled flexible container to thereby change the shape of the container.

15. A process according to claim 1 wherein the hermetic sealing is accomplished by applying to the area to be heat sealed of the flexible container heat sealing temperature and pressure necessary for melt bonding the heat sealable resin film.

16. A process according to claim 1 wherein the coefficient KF of flatness of the sealed packaged article is maintained at a level not exceeding 0.15.

17. A process according to claim 1 wherein the sterilization is accomplished by maintaining the sealed packaged article in a heating medium of a temperature of 130* to 160*C. for 1 to 8 minutes under a pressure of 1.7 to 8 Kg/cm2 gauge.

18. A process according to claim 1 wherein the heating medium is selected from saturated steam and a mixture of saturated steam with 10 to 30 % of compressed air.

19. A process according to claim 1 wherein the heating medium is compressed hot water maintained at a pressure of 1.7 to 8 Kg/cm2 gauge and a temperature of 130* to 160*C.

20. A process according to claim 1 wherein the sealed packaged article is maintained at a temperature of 85* to 98*C. prior to the heat sterilization.

21. A process according to claim 1 wherein the heat sterilized sealed packaged article is cooled under a pressure higher by 0.1 to 1 Kg/cm2 than the saturated vapor pressure corresponding to the sterilization temperature.

22. A process according to claim 1 wherein the heat sterilized sealed packaged article is cooled by introducing it directly into cooling water from the heating medium.

23. A process for the preparation of high-temperature short-time sterilized packaged articles which comprises the steps of providing a flexible container having a heatsealable resin film at least on an area to be heat sealed of the inner surface thereof with said heat sealable resin being a crystalline thermoplastic resin having a softening of melting point of from 130* to 250*C., filling an article to be sterilized in the flexible container, removing noncondensable gases present in interior voids of the flexible container, hermetically sealing the flexible container by application of heat in such a manner that the coefficient of flatness in the resulting seaLed packaged article is maintained at a level not exceeding 0.25, said coefficient of flatness being defined by the following formula

24. A process for the preparation of high-temperature short-time sterilized packaged articles which comprises the steps of providing a flexible container having a heat-sealable resin film at least on an area to be heat sealed of the inner surface thereof with said heat sealable resin being a crystalline thermoplastic resin having a softening or melting point of from 130* to 250*C., filling an article to be sterilized in the flexible container, removing non-condensable gases present in interior voids of the flexible container, hermetically sealing the flexible container by application of heat in such a manner that the coefficient of flatness in the resulting sealed packaged article is maintained at a level not exceeding 0.25, said coefficient of flatness being defined by the following formula