Definition of Secondary Sterilization
Some breathable materials (such as natural casings, protein casings, cellulose casings, cellophane casings, etc.), filled products (such as sausages, and ham products), or naked products (such as roasted meat products) are cooked after cooking, in order to facilitate storage and extend shelf life, a second packaging is required. In the process of cooling and secondary packaging, the product’s surface will inevitably be more or less contaminated. Therefore, after the packaging is completed, it needs to be sterilized again, which is called secondary sterilization.
Pollution Source
How minimize contamination is a key control point in the production of secondary sterilized meat products.
After the researchers checked the packaging environment, and the sanitation of the operator’s hands and tools, they found that these places or parts contained a certain amount of microorganisms. The specific quantity is as follows: 100-1000 pieces/c㎡ of air; 10,000-1,000,000 pieces/c㎡ of manpower; 1,000-100,000 pieces/c㎡ of work surface; 100-1,000 pieces/c㎡ of electronic scale surface; 100-1,000 pieces of plastic turnover box /em; 10,000 to 10,000,000 work clothes/c㎡. It can be seen from this set of data that if the environment and facilities in the packaging room are not strictly sanitized, the entire packaging process will become a process of inoculating food with bacteria. In order to reduce secondary pollution to a minimum, we have carried out a lot of detailed tests and inspections and formulated a reasonable solution.
Before the production personnel enter the workshop, the following procedures shall be strictly followed:
1.Change clothes – Put on slippers and enter the shower room to take a bath – Put on sterilized work clothes and rubber shoes – Arrange the clothes and hats and enter the hand washing and disinfection procedure.
2. Wash hands and disinfect.
3. Rinse with clean water – wash with soap solution – rinse with clean water – soak in disinfectant for more than 3s – rinse with clean water – dry hands – disinfect with 75% alcohol. The shoes are then sterilized by a shoe sterilizing tank – blowing the dust off the body through the air shower.
4. Put the received packaging materials into the buffer room for ultraviolet disinfection. After disinfection, clean the floor of the workplace and then disinfect the operating utensils, containers, desks, electronic scales, and turnover boxes with 2/10,000 chlorine dioxide. Then disinfect the operator’s hands with 75% alcohol and wear a mask before operating.
5. During the work process, keep the working environment clean and hygienic. The operator’s hands are disinfected with 75% alcohol every 30 minutes.
6. At the end of the work, thoroughly improve all the hygiene in the work area, and strictly disinfect the operating utensils, containers, desks, electronic scales, turnover boxes, etc. with 2/10,000 chlorine dioxide. Turn on the ozone generator for 60 minutes to disinfect the operating room before leaving the workplace. Reduce the total number of colonies in the air to 10/c㎡, which meets the requirement of <50/c㎡.
7. At present, the combined use of the dynamic food sterilizer is effective. The principle of the equipment for sterilization, disinfection and dust removal is the use of a dual-electrode plasma electrostatic field to decompose and break negatively charged bacteria, and polarize and adsorb the dust. The components such as drug-impregnated activated carbon, electrostatic net, photocatalyst catalytic device, and other components are combined for secondary sterilization and filtration. The high volume and rapid circulation of the treated clean air keep the controlled environment at a “sterile clean room” standard. It is harmless to the human body if it is used continuously under the condition of people. The equipment can sterilize quickly and thoroughly, with a killing rate of 97% for mold and 99.99% for other harmful bacteria. Work clothes and rubber shoes are washed and irradiated under UV light for 1 to 2 hours. The irradiation range of the UV lamp is 1.5 ~ 2m.
Performance Problems and Solutions
1. Possible problems: water, discoloration, and bulging bags.
2. Reason.
2.1. After the product is evacuated, negative pressure is formed inside, the product is always under pressure, and the internal water is squeezed out.
2.2. After the product is cooked, it is exposed, the cooling is not complete, the water vapor is not completely dissipated, and the water vapor is released again during the secondary sterilization.
2.3. The organizational structure of the product is not good, the quality of the water-retaining raw materials is poor, and the water is lost.
2.4. The product pursues the yield excessively, and the formula moisture is relatively large.
2.5. The drying effect of the product is poor, resulting in excessive moisture content in the product.
2.6. The temperature difference during product storage and sales and transportation changes greatly, resulting in the product being easily corrupted.
2.7. Failure to store the product as required during the sales process leads to the corruption of the product expansion bag.
2.8. The secondary sterilization temperature is too high, causing the product structure to be destroyed and the product to be effluent.
3. The solution.
3.1. Before the product is cooked, a drying process is added to form a hard shell on the surface to prevent the penetration of water, and at the same time, the surface of the product is ruddy and beautiful.
3.2. After the product is cooked, hang the product at 10~15℃ and 25%~35%RH humidity environment to completely dissipate the water vapor on the surface of the product, so as to ensure that the water vapor will not be released in large quantities during the secondary sterilization.
3.3. Reasonably control the yield of the product to control the moisture of the product.
3.4. After the product is cooked and smoked, there must also be a drying process, one is dehydration, the other is to prevent smoke, and the humidity in the furnace should not be higher than 38% RH during smoking.
3.5. The storage temperature of the product is kept at 0～4℃ to avoid damage to the structure of the product caused by the large temperature difference.
3.6. Formulate a reasonable secondary sterilization temperature, which generally should not exceed 95 °C (sterilization above 95 °C will destroy the structure of low-temperature meat products and cause the product to effluent).
3.7. Reasonable and effective use of preservatives.
3.8. Control the hygienic quality of accessories.
In the process of low-temperature storage, the spoilage of meat products is usually caused by two reasons: First, due to insufficient thermal processing, the residual heat-resistant Bacillus overgrowth, and reproduction. Second, during the packaging process, bacteria were brought in due to secondary pollution, and these bacteria grew and multiplied in large numbers. When the meat products are vacuum-packed, sterilized for the second time, and all the heat-resistant spores are fully killed, the key factor that causes the spoilage of meat products becomes the overgrowth and reproduction of the spores.
Therefore, controlling the original number of spores in raw and auxiliary materials is the key to ensuring a longer storage period for meat products. In order to understand the source of Bacillus contamination in meat products, the experiments and investigation data of the storage and preservation experts of the China Animal Products Processing Research Association on the hygienic conditions of various raw and auxiliary materials required for the production of meat products were cited.
The data shows that the excipients, especially spice, have a high content of bacillus, which is the main source of bacillus in meat products. Some companies produce two kinds of spices: one is ordinary, the other is sterilized and refrigerated, and the second is recommended.
