Discussion on the technology of prolonging the she

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Discussion on the technology of prolonging the shelf life of active lactic acid bacteria beverages

there are many problems affecting the quality of active lactic acid bacteria beverages in the sales process, which shortens the shelf life of products. How to prolong the shelf life of active lactic acid bacteria beverage is expounded from the aspects of raw materials, processing technology, production equipment, packaging materials, health management, transportation and so on

the common quality problems of the active lactic acid bacteria beverage are:

bad package phenomenon:

during the sales and storage of the active lactic acid bacteria beverage, the bad package phenomenon (bulging package, acid package, mold package, mucilage package) is most likely caused by the growth and reproduction of the yeast, coliform group, fine bacteria, mold and other miscellaneous bacteria in the bag to produce gas and acid. From the perspective of enterprise production health management, There may be problems such as the pollution of working starter by yeast, the pollution caused by the quality, production and hygiene of raw milk, the quality of packaging materials, storage and transportation, etc

to solve these problems that lead to bad packages, we can start from the following aspects:

1. Clean and disinfect the fermentation agent production equipment to eliminate sanitary dead corners. In the process of preparing working fermentation agent, use sterile tools to operate in a sterile room, and effectively operate the equipment used. As long as such cleaning and disinfection, The air entering the starter production room must be filtered to ensure the sanitation of the environment, tools and personnel

2. Strictly controlling the microbiological index of milk source is the foundation of producing qualified products. Raw milk must be stored after cooling. The storage temperature should be controlled within 6 ℃ and the storage time should not exceed 24 hours, which can further open up a larger utilization market with methyl methacrylate. In the production process, the sterilization temperature is controlled at 90 ℃ ~95 ℃, and the time is 15~20s. The bacteria in the raw materials are killed to meet the required organizational structure and flavor

3. Strengthening the hygiene requirements and on-site hygiene management in the production process, improving the production environment and the quality of employees, and maintaining good personal hygiene habits will directly contribute to improving product quality. Ensure that the number of bacteria in the air of the production environment ≤ 300m-3, yeast and mold ≤ 5.0m-3

equipment sanitation: the installation of pipelines should be reasonable, effective CIP cleaning should be carried out, the concentration, temperature, flow and circulation time of cleaning solution should be controlled to ensure the effectiveness of cleaning, manual cleaning equipment should not leave dead corners, and the filling machine should be cleaned and disinfected after repairing and replacing parts to ensure the cleanness and sanitation of the equipment

4. The quality of the packaging material is unqualified, and it cannot play its due role in avoiding light and preventing the penetration of wet air. There are micro pores, trachomas and uneven thickness of the packaging material on the surface of the composite film, resulting in improper incision, uneven heating, lax sealing, leakage, as well as unsanitary packaging material and incomplete cleaning and disinfection, which may cause bad packaging. Therefore, the hygienic quality of the packaging film is very important, The packaging materials must be cleaned and used after ultraviolet disinfection when entering the filling room. Packaging materials should also be strictly checked before entering the factory to ensure the quality of materials. 5. Wear and tear during transportation, extrusion and storage and transportation are not operated under the cold chain conditions, which will cause package damage. In order to ensure product quality, storage and transportation, a cold chain must be formed

sedimentation phenomenon

sometimes there is sedimentation in some bags of lactic acid bacteria drinks sold in the market, and the upper layer is clear liquid and the lower part is sticky. There are many reasons for precipitation, not only because of protein precipitation. If such materials with serious fire hazards are allowed to be used legally, the addition of thickener, citric acid, etc. or the improper feeding sequence will lead to precipitation. The main causes of precipitation are water quality, acid regulation, feeding sequence and dosage

to avoid precipitation, corresponding technical measures can be taken: first, the water must meet the national drinking water standard, and the hardness must be lower than 6 degrees, otherwise the precipitation will not decompose at the current processing temperature, which is inevitable. At present, general manufacturers use purified water filtered by sand rods, and the hardness of water sometimes cannot meet the requirements. Ion exchange method or most dialysis method can be used for deionization. In the process of adjusting the acidity of fermented milk, at present, general manufacturers use citric acid to adjust the acidity. After studying and comparing the relationship between pH value and precipitation after acid adjustment, it is found that when the preparation solution is adjusted to pH value of 3.8~4.0, the precipitation phenomenon is the smallest, and at the same time, the taste of lactic acid bacteria beverage is excellent. When producing lactic acid bacteria beverage, stabilizer, granulated sugar, sour agent, essence, etc. should be added successively. If the feeding amount and feeding sequence are improper, sedimentation will occur. The effect is better when the dosage of thickener is 0.3~0.4% and pH value is 3.8~4.0. After the fermented milk is mixed with syrup and thickener, homogenization under the pressure of 15~20mpa is also a necessary operation to prevent precipitation. After homogenization, the stock solution continues to be stirred slowly to promote hydration and prevent particle recombination. Citric acid is used in acid mixing. Special attention is paid to the operation of adding citric acid, which is also one of the factors that cause precipitation of products. It must be noted that at low temperature, they should be in uniform and slow contact with protein particles. The concentration of acid should be as thin as possible, the adding speed should be slow, and the mixing speed should be fast. If there is a spray device to add acid, the effect will be better

in order to effectively prevent the growth and reproduction of mold and yeast within the shelf life of the product and reduce the spoilage of bad bags, precipitation, acid bags and other phenomena, adding delvocid to the active lactic acid bacteria drink has a strong inhibition on fungi (mold and yeast). The addition amount of 10 ~ 20ppm can prolong the shelf life of the product, which is 5 ~ 6 times that of the original product

changes in acidity during the shelf life

the acidity increases during the shelf life, and its taste decreases, affecting the sales of products. The possible reasons are that due to poor sanitary conditions, incomplete equipment cleaning, resulting in miscellaneous bacteria pollution, or due to incomplete sterilization of dispersion medium, a large number of bacteria will accelerate acid production. The heat-resistant spores in the beverage will gradually turn into nutrient cells of bacteria during the storage process, resulting in acid packets and increased acidity of the product during the storage process

due to the imperfection of the cold chain, lactic acid bacteria continue to produce acid during the storage and sales of active lactic acid bacteria drinks, making the taste sour. We have made a comparative experiment on the number of lactic acid bacteria and the change of pH value of the active lactic acid bacteria beverage at the temperature of 5 ℃ and 32 ℃, as shown in the figure:

■ comments

the pollution of yeast, coliform, bacteria and mold in the active lactic acid bacteria beverage is an important factor to shorten the shelf life. Therefore, it is necessary to strengthen the hygiene requirements and on-site hygiene management in the production and processing process, improve the quality of employees and maintain good personal hygiene. Creating good manufacturing practices (GMP) is the requirement to ensure that products meet high quality. Therefore, enterprises should strictly control the quality of raw milk and the strict inspection of other raw and auxiliary materials. The active lactobacillus beverage must be transported and stored in the cold chain, which is an important factor to ensure the shelf life of products

■ little knowledge

active lactic acid bacteria beverage is a novel milk containing beverage made from fresh milk fermented by lactic acid bacteria. Because this product is a fermented product, it has the similar characteristics of yogurt. ① The lactose contained in the milk in the product is decomposed into glucose and galactose through fermentation, and then converted into lactic acid and other organic acids. After being absorbed by the human body, it can participate in the synthesis of brain fat and nerve substances in young children, and can also improve the utilization rate of milk fat. ② It is suitable for people with lactose intolerance. After fermentation, lactose is converted into lactic acid and other substances, reducing the lactose content in milk. ③ Drinking this product for a long time can improve constipation and help digestion. This is because lactic acid and other organic acids produced by fermentation products can stimulate the intestinal tract and strengthen peristalsis. (end)

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