PASTEURIZATION

From Big Medical Encyclopedia

PASTEURIZATION (by name fr. chemist and microbiologist L. Pasteur ) — a way of disinfecting of foodstuff and other substrates by their heating to temperature which is not reaching 100 °, but sufficient for death of vegetative forms of pathogenic and opportunistic microorganisms.

To the item it was for the first time offered by L. Pasteur in 1865 for prevention of damage of wine. For destruction of microorganisms L. Pasteur suggested to warm up wine at t ° 65 — 70 ° apprx. 10 min. without access of air, and then quickly to cool it. At the same time in addition to death of microorganisms it is terminated also enzymes. Such processing called pasteurization ensured long safety of wine, promoted improvement of its quality.

Soon according to L. Pasteur's proposal pasteurizations began to subject also beer. Further pasteurization gained great value for disinfecting of a number of foodstuff, and first of all milk.

Distinguish long (usual) P., at a cut the pasteurized materials maintain at t ° 60 — 68 ° within 30 min. and then quickly cool, short-term at t ° 70 — 80 ° during 15 — 20 sec. and instant when temperature is led up to 85 — 90 ° (sometimes up to 100 °) and at once reduce. The given modes P. can vary depending on the pasteurized objects, their volume and the used equipment. At P. vegetative forms of the vast majority of pathogenic microorganisms perish, the general microflora considerably decreases (by 99,0 — 99,5%), but disputes of bacteria remain viable. As P. does not provide full sterilizations (see) the processed materials, it is necessary to store them on cold for the prevention of germination a dispute and reproduction of microorganisms.

In laboratory practice of P., as a rule, carry out on the water bath.

An example of use of P. in laboratory practice is warming up of mix of a bacteriophage and enterobakteriya in a beef-extract broth at t ° 58 ° within 1 hour for the purpose of destruction of enterobakteriya and preservation of a bacteriophage. For sterilization bacterial, the mediums containing proteinaceous liquids apply fractional P. — tindallization (see), at a cut warming up is repeated by 4 — 6 times at t ° apprx. 60 ° within 40 — 60 min. with daily intervals. In intervals between warmings up mediums maintain at t ° 25 — 37 °; in such conditions manage to sprout all disputes, and the formed vegetative forms of microorganisms perish at the subsequent warmings up. Such processing is rather reliable, it is applied also to sterilization biol, liquids and solutions of the pharmaceuticals which are not maintaining high temperature.

The item allows to preserve food stuffs; at the same time slightly change their organoleptic and physical. - chemical properties, the most part of biologically active agents — vitamins, enzymes, etc. remains.

Methods P. apply in the milk, canning, ovoshchesushilny and meat industry, being guided at the same time by the existing instructions and industry standards. For this purpose use pasteurizers of various systems. In the milk industry depending on a type of the made products use certain modes P. So, the milk intended for direct consumption will be pasteurized at t ° 74 — 76 ° during 20 sec., the milk intended for production of fermented milk products — at t ° 85 — 87 ° within 5 — 10 min., for production of cottage cheese — at t ° 78 — 80 ° during 20 — 30 sec. etc. In the canning and ovoshchesushilny industry by production of vegetable, fruit and berry juice, marinades, compotes, jelly P. make at t ° 85 — 95 ° within 15 — 20 min. depending on a type of canned food. In the meat industry by production of nek-ry types of canned meat P. carry out at t ° 80 — 82 ° within 100 — 115 min. depending on a type of canned food.



Bibliography: Mazokhina - the Piston-to about in a H. N and d river. The analysis and evaluation test of canned food on microbiological indicators, M., 1977; The Collection of technological instructions for production of milk, cream and fermented milk products, under the editorship of M. G. Demurov and V. I. Sirik, M., 1961; Sokolov A. A., etc. Technology of meat and meat products, M., 1970; Pasteur L. Etudes sur le vin, P., 1866.


H. S. Goryachkina; Yu. P. Pivovarov (pitas.).

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