Frozen culinary products are a relatively new branch of the food industry, has received recent widespread in a number of foreign countries, and especially in America.
In the United States of frozen culinary products produced in 93% of grocery stores.
In 1954 144,7 of all th. Tons of various frozen food products were produced, and in 1955, the release of these products increased to 242,7 thousand. Mr.
The range of frozen food products is quite diverse. Freezes entire meals, as well as individual dishes of meat, poultry, fish, vegetables, salads, pastries, fruit desserts, and so on. D.
Freezing is carried out in freezers at temperatures —30 ° C - 40 ° C. Due to the rapid freezing at these temperatures, the product does not lose its original qualities and can remain frozen for a long time (up to 6 months).
The advantage of these products is a great saving of time for their preparation (15 — 20 minute warm-up), therefore frozen culinary products are very popular among consumers. The production of these products is of great interest and opens up broad prospects not only for individual consumption, but also for catering enterprises — restaurants, dining cars, on airlines and long-distance bus routes.
The range of food products to be frozen in the developed vnih; here experiments on the freezing of meat have been conducted, fish, poultry, side dishes, sauces, confectionery and so on. d.
Through a variety of parts and a suitable value pH, ready-to-cook products before freezing are often fertile ground for the growth of microorganisms. Freezing food does not make them sterile.
Although the number of bacteria in the first days after freezing decreases, some of them can survive during long-term storage of the product. This applies to pathogens of food poisoning - bacteria Staphylococcus, Salmonella, you. botulinus. The toxin released by these bacteria also does not deteriorate upon freezing and refrigerated storage of products. In the study of chicken salad, it was found that five of eight samples after five months of storage at —10 —12 ° C contained a toxigenic strain of Staphylococcus aureus.
To identify the effect of low temperatures on pathogenic bacteria, culinary products were inoculated with various strains of bacteria that cause food poisoning. After freezing and storing the samples at -17,8 ° C for several months, it was found that 10% of bacteria survived in the product for more than 6 months. In the finished frozen chicken, seeded with the bacteria you. botulinus, after defrosting and two-day storage at a temperature of 30 ° contained a toxin (shorter shelf life in a defrosted state has not been studied).
In the study of bacterial contamination 40 samples of frozen food products in retail chain in 25% of the samples studied was found toxigenic Staphylococcus aureus.
As a result of research over 100 different types of food products prepared for sale, it was found that the total number of bacteria shatters ranged from 50 1 ppm kDa to living cells on 1 g (straight through under the microscope will return results from the 500 40 to kDa million. on 1 g). Number of coliform bacteria in some samples reached 200 cells, although in most cases there were less than 50 1 in the city
Usually high levels of coliform bacteria in the products mentioned tucked sour cream sauce.
Contamination of meat frozen food products ranged from thousands 20. 300 before the thousand. 1 of bacteria on
In the study of several batches of frozen pies filled with beef, poultry and fish, purchased in stores in various cities of the United States, it was found that of 132 pies, 84% had a total population of less than 100 thousand and almost 60% — lower than 25 thousand per 1 g Of the 42 pies stuffed with beef meat, 85,8% had a total seed rate below 100 thousand by 1 g. In the pies, the seed rate of which was higher than 100 thousand, an increased content of enterococci and Escherichia coli bacteria was observed. About the same contamination was in pies stuffed with chicken and turkey meat. In pies with fish filling, the number of bacteria ranged from 2 thousand to 14 thousand on 1.
According to other researchers, the total contamination of poultry pies with filling ranged from 4 thousand. Up to 3 million. On I g of the product, the number of bacteria in 50% of samples did not exceed thousand 100. 1 in the city
It was found that in pies stuffed with beef and poultry from 188 samples, 93% had a total seed rate below 100 thousand, 83% below 50 thousand and 75% below 25 thousand at 1. In the majority of the studied samples, it was found the presence of enterococci,
|Ware||Initial seeding to 1 g||Storage temperature, ° С||Contamination on 1 g after storage days|
|Beef Stroganoff of frozen meat. . .||-18||22||13|
|Beef Stroganoff of chilled meat||-18||—||15|
|Lamb chops. . .||415||-18||—||140|
|Chicken boiled. . .||32 тыс.||-18||500|
|Fried chicken||90 тыс.||-18|
are always present in larger amounts than coliform bacteria, and were more resistant to low temperatures.
The number of bacteria in frozen culinary products after 3 months of storage at temperatures —18 and —25 ° (in thousand per 1 g)
|Ware||Storage temperature, ° С|
|Beef spirits. . .||40||73|
|Pechenka in couce||3,9||5,5|
|Pechenka without breading. .||7,5||9|
|Empanadas. . .||8||4|
Bacterial contamination of meat and fish food products by freezing and storage process has been studied in vnih on samples manufactured in the restaurant and at the factory-kitchen. Data for meat dishes are presented in Table. 53 and 54.
As can be seen from the table. 53 the most seeded were boiled chicken, chakhokhbili and fried chicken, and 25 — 90% of the bacteria seeding these products were psychrophiles reproducing at 2 ° С. Other samples of meat dishes were less seeded.
The microflora of meat to a large extent has been presented spore-forming bacteria that are resistant to the stage of the dispute to the heating and cooling; so at the end of the storage amount of bacteria remained roughly at the level of the source.
Bacterial contamination of food products of fish is shown in Table. 55.
|Ware||Initial seeding na1 g||Storage Temperature, C||Contamination on 1 g after storage days|
|Boiled fish (perch).||280||- 18||52||35|
|stuffed pike||290||-! 8||64||25|
|Fish sauce. . . .||326||-18||96||53|
|Fish cutlets. .||342||-18||8||19|
|Pilaf fish||670 тыс.||- 18||227 тыс.|
Contamination of fishery products, except pilaf small. A significant part of the microflora of these products is represented by spore-forming bacteria. Microbiological studies of fish fingers production line at Mosrybkombinate of 17 samples ready sticks there was not a single case of contamination in excess of 10 thousand. On 1 of bacteria
When researching various vegetable dishes and side dishes (peas, corn kernels, spinach, potatoes prepared in various ways, and products made from it, green beans, dishes from corn, beans and salt pork, carrots, etc.) it was found that in Mainly for all these products, bacterial contamination fluctuated within less than 50 thousand bacteria at 1. In fact, 80% of the samples had a total contamination below 20 thousand bacteria by 1 g, and 70,8% had seeding ranging from 0 to 10 thousand. Only Single samples There were more than 100 thousand bacteria per 1 g, which was due to insufficiently good processing of raw materials.