Control of the hottest food spoilage 0

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Control of food spoilage

③ sorbic acid and potassium sorbate are colorless, tasteless and odorless chemicals. Sorbic acid is insoluble in water (600:1), soluble in alcohol (7:1), and potassium sorbate is soluble in water. They have extremely weak toxicity to people. They are safety preservatives widely used in various countries in recent years, and they are also one of the two national standard organic preservatives allowed to be used in China

sorbic acid molecule can combine with sulfhydryl (- SH) in microbial cell enzyme system, so as to achieve the purpose of inhibiting microbial growth and antisepsis. Sorbic acid and potassium sorbate have inhibitory effects on bacteria, yeast and mold, but have little effect on anaerobic microorganisms and Lactobacillus acidophilus. Its anti-corrosion effect is wider than benzoic acid, and it is suitable for use below pH. The effect decreases with the increase of pH value, and the bacteriostatic effect is the best at pH 3. It can be used to control lactic acid fermentation when pickled cucumber

the allowable dosage is 1.0g/kg for soy sauce, vinegar, jam, margarine, agar milk sugar, dried fish products, soybean milk beverage, soybean vegetarian food, pastry filling, etc. (in terms of acid, 1g sorbic acid is equivalent to 1.33g of potassium salt); The maximum dosage of low salt pickles, flour sauces, candied fruits, hawthorn and fruit leaf dew is 0.5g/kg; The maximum dosage of fruit juice, fruit dew and fruit wine is 0.6g/kg; The maximum consumption of steam water and sparkling wine is 0.2g/kg; Concentrated fruit juice should be less than 2g/kg

④ sodium diacetate (abbreviated as SDA)

sodium diacetate is a white crystal with slight acetic acid smell and is very soluble in water (1g/ml); The pH value of 10% aqueous solution is 4.5 ~ 5.0. Sodium diacetate is low-cost, stable in nature, and has significant anti mildew and anti-corrosion effects. It can be used for mildew prevention and corrosion prevention of grain, food, feed, etc. (the general dosage is 1g/kg), and can also be used as sour agent and quality improver. The product added to the feed can improve the potency of protein, increase palatability, improve the meat, egg and milk production rate of feeding animals, prevent enteritis and improve immunity. It is a newly developed additive, which is recognized as a generally recognized safe substance by the U.S. Food and Drug Administration (FDA). And in 1993, the allowable limits of SDA in food, medicine and cosmetics were removed

⑤ o-phenylphenol (OPP) and o-phenylphenol sodium (SOPP)

are mainly used to prevent mold growth, which has a good anti mold effect on citrus peel. The allowable dosage is less than 100mg/kg (calculated by o-phenol)

⑥ biphenyl

has a good control effect on the mold on the peel of lemon, grape and citrus, especially on Penicillium digitalis and Penicillium Italis. Generally, it is not directly used in the peel, but soak the drug in paper, and then put the paper soaked with the drug solution in the packaging container for storage and transportation, and let it volatilize slowly (the vapor pressure is 1.3pa at 25 ℃). After the peel is adsorbed, the antiseptic effect can be produced. The allowable pesticide residue per kilogram of fruit should be less than 0.07g

⑦ thiabendazole (thiabendazol 1. vertical universal friction and wear tester e, abbreviated as TBZ)

TBZ is a new anti mildew agent invented in the United States, which is suitable for citrus, banana and other fruits. The allowable residue after use is less than 10mg/kg for citrus; Bananas less than 3 mg/kg; Banana pulp is less than 0.4 mg/kg

in a word, all chemicals used in food must be non-toxic. After long-term animal tests, scientific evaluation should be made on the performance of the antirust agent coated on the processing surface of the machine. The table shows the local amplification safety and use standards of organic preservatives issued by the Special Committee on food additives of the United Nations Food and Agriculture Organization (FAO) and the World Health Organization (who)

Table allowable daily intake of preservative (ADI, mg/kg body weight) (fao/who)

preservative ADI (mg/kg body weight) preservative ADI (mg/kg body weight)

benzoic acid, sodium benzoate 0 ~ 5 * sodium propionate, calcium propionate are non-toxic, and there is no restriction

sorbic acid, sodium sorbate 0 ~ 25 * o-phenol 0 ~ 0.2

p-hydroxybenzoate 0 ~ 10 * thiabendazole 0 ~ 0.05

* is the combined quantity

⑧ lysozyme

lysozyme is a white crystal, containing 129 amino acids, and its isoelectric point is 10.5 ~ 11.5. Soluble in food grade salt water, relatively stable in acidic solution, with no change in activity at 55 ℃

lysozyme can dissolve the cell walls of many kinds of bacteria to achieve the purpose of bacteriostasis and sterilization, but it is almost ineffective for yeast and mold. The optimum pH value of bacteriolysis is 6 ~ 7; The temperature is 50 ℃. Carboxyl and sulfuric acid in food can affect the activity of lysozyme, so it is better to use it with other antibacterial substances such as ethanol, phytic acid, polyphosphate, etc. At present, lysozyme has been used in pasta. The factory has achieved the preservation of daily production, cooked aquatic food, ice cream, salad, caviar and other foods in phase 1

⑨ trehalose

trehalose is a non-toxic disaccharide with low calorific value. The reason why it has good anti-corrosion effect is due to its anti drying characteristics. It can form hydrogen bond connection at the water loss part of dry biological molecules, form a protective film, and form a crystal like vitreous body. Therefore, for frozen and dried food, it can not only play a good anti-corrosion role, but also prevent quality changes

⑩ mannan

mannan is a colorless, non-toxic and odorless polysaccharide. Spraying, dipping and coating with 0.05% - 1% mannan aqueous solution on the surface of fresh food or adding it into some processed food can significantly prolong the fresh-keeping period of food. For example, strawberries were soaked in 0.05% mannan aqueous solution for 10s, air dried, stored for 1 week, only the epidermis was slightly tarnished, and mold did not grow for 3 weeks; The control group lost luster after 2 days and began to mold on 3 days

⑾ chitosan

chitosan, namely deacetylated chitin (c30h50n4o19), is one of the mucopolysaccharides, which is white powder, insoluble in water, soluble in hydrochloric acid and acetic acid. It has a good inhibitory effect on Escherichia coli, Staphylococcus aureus, Bacillus subtilis, etc., and can also inhibit the physiological changes of fresh food. Therefore, it can be used as a preservative for food, especially for fruits and vegetables. When used, chitosan is generally dissolved in acetic acid, such as coating apples with 2% modified chitosan

12 hydrogen peroxide

hydrogen peroxide is an oxidant, which not only has bleaching effect, but also has good sterilization and deodorization effect. The disadvantage is that hydrogen peroxide has certain toxicity and destructive effect on vitamins and other nutrients, but it has strong bactericidal power and remarkable effect. However, it needs to be heated or treated with catalase to reduce its residue

it is commonly used for anti-corrosion of cut noodles, noodles, fish cakes, etc. the allowable residue is less than 0.1g/kg, and other foods are less than 0.03g/kg

⒀ nitrate and nitrite

nitrate and nitrite are mainly used as chromogenic agents for meat. Nitrite reacts with heme to form nitroso myoglobin, which makes the meat bright red. In addition, nitrate and nitrite also have the effect of delaying microbial growth, especially preventing the germination of heat-resistant Clostridium botulinum spores. However, nitrite can be converted into nitrosamine in muscle and has carcinogenic effect. Therefore, its use should be strictly limited in meat processing. At present, no complete substitute has been found

the allowable dosage is below 0.07g/k for ham, bacon, sausage, bacon, whale meat, etc; Fish sausage and fish ham are less than 0.05g/kg (calculated by nitrite residue)

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