Food spoilage signals include becoming sticky, sour, smelly and so on.

1. Viscosity

The viscosity of spoiled food is mainly caused by polysaccharides formed by bacterial growth and metabolism, which often occurs in foods mainly containing carbohydrates. Common microorganisms that change food education are Alcaligenes mucilaginosus, Alcaligenes-like, Achromobacter, Aerobacillus, Lactobacillus, Leuconostoc, etc. A few yeasts also make food corrupt and sticky.

2. turning sour

food turning sour often occurs in carbohydrate-based foods and dairy products. The sourness of food is mainly caused by the growth and metabolism of spoilage microorganisms. The main microorganisms include acetic acid, propionic acid, Pseudomonas, Micrococcus, Streptococcus lactis and lactic acid bacteria, etc. A few molds, such as Rhizopus, also use carbohydrates to produce drums, thus causing food spoilage.

3. Odor

Food odor is mainly caused by bacteria decomposing protein-based foods to produce organic amines, ammonia gas, sulfur intoxication, manure and so on. Common bacteria that decompose protein are Fusobacterium, Proteus, and Fusobacterium.

food preservation method recommendation:

1. Low temperature storage method

Low temperature storage method is a common method for storing cooked food. Its main principle is to effectively inhibit the growth and reproduction of microorganisms through low temperature, reduce the activity of enzymes, weaken the chemical reaction in food, and better maintain the original flavor and nutritional value of food.

2. High-temperature storage method

The high-temperature storage method is often used in the catering industry to store food, because microorganisms have weak tolerance to high temperature, and can effectively kill microorganisms when the temperature increases. And destroy the activity of the enzyme. It can prevent the influence of microorganisms on food and achieve the purpose of storing food. The method is to first boil or steam the food thoroughly, and then take it out or soak it in the original soup.

3. Ventilation storage method

Ventilation storage method is mainly suitable for storing grain, dry food and food that needs air drying. They are all characterized by fear of mildew and cover. For example, rice, noodles, peanuts, vegetables and other foods need ventilation when stored. This can make mold difficult to grow, keep the original ingredients of food and reduce mildew.