Food sterilization technology mainly includes heat sterilization and non-thermal sterilization. Among them, heat sterilization mainly includes: moist heat sterilization, dry heat sterilization, microwave sterilization, electrothermal sterilization and electric field sterilization; non-thermal sterilization mainly includes: chemical and biological sterilization, irradiation sterilization, Ultraviolet sterilization, pulse sterilization, ultra-high static pressure sterilization, pulsed electric field (PEF) sterilization, and vibration magnetic field sterilization. The following is a detailed introduction to these sterilization technologies:

First, heat sterilization
1, damp heat sterilization

Heat sterilization is a heat treatment form with the main purpose of killing microorganisms, and moist heat sterilization is one of the most important methods. It is a sterilization method in which steam or hot water is used as a heat medium or directly by steam jet heating.

A heat energy converter (such as a boiler) is used to convert the heat energy of combustion into hot water or steam as a heating medium, and then heat energy of hot water or steam is transferred to the food by a heat exchanger, or steam is directly sprayed into the food to be heated.
2, dry heat sterilization


Microwaves are sterilized by burning or dry hot air and are called dry heat sterilization. Although the dry main hot air is not as strong as the wet heat steam, it is easy to use and is suitable for sterilization of glassware and porcelain, so it is widely used in laboratory and production practice.

Dry heat refers to high heat with a relative humidity of less than 20%. Dry heat sterilization is conducted by air and has a slow heat transfer effect. The general propagule can be killed in dry heat at 80-100 ° C for 1 hour, and the spores need to be killed at 160-170 ° C for 2 hours.
3, microwave sterilization Microwave (microwave) refers to the electromagnetic wave with a wavelength of about 1m ~ 10mm, often divided into four bands of meter wave, centimeter wave, millimeter wave and sub-millimeter wave.
The frequency of the microwave (300MHz to 300GHz) is between the radio frequency (ultra-short wave) and the far-infrared frequency (low-frequency end). Due to its high frequency, it is also called UHF electromagnetic wave in some cases.
4, electrothermal sterilization Electrothermal sterilization, also known as "ohmic sterilization", it uses electrodes to pass current through the object, due to the existence of impedance loss, dielectric loss, etc., eventually converts electrical energy into heat, so that the inside of the food generates heat to achieve the purpose of sterilization.


Second, non-thermal sterilization
1. Chemical and biological sterilization Mainly refers to the purpose of inhibiting bacteria or sterilizing by adding bacteriostatic agents and preservatives to foods.
2, ultraviolet sterilization UV sterilization technology is the use of ultraviolet radiation to cause the molecular structure of the microbial cell core protein on the surface of the object to change and cause death.
3, ultra high static pressure sterilization


The ultra-high static pressure (UHP or HHP) treatment technology of food refers to placing the food sealed in the elastic container in a pressure system of water or other liquid as a pressure transmitting medium, and treating it with a pressure of 100 MPa or more to achieve sterilization and destruction. Enzymes and improving the functional properties of foods.

Ultra-high pressure treatment is usually carried out at room temperature or at a lower temperature. Under certain high pressure, food protein denaturation, starch gelatinization, enzyme inactivation, life stop, and microorganisms such as bacteria are killed.
4. Pulsed electric field (PEF) sterilization Pulse electric field sterilization is to place food in an instantaneous high-voltage electric field generated between two electrodes. Because high-voltage electric pulse can destroy the cell membrane of bacteria, change its permeability and kill cells.
5, vibrating magnetic field sterilization magnetic sterilization using 6000 magnetic strength, the food is placed between the N pole and the S pole, after continuous swing, without heating, can achieve 100% sterilization effect, no food ingredients and flavors influences.
6. Radiation sterilization food irradiation refers to the use of radiation to irradiate food (including raw materials), delay the development of certain physiological processes (germination and maturation) of fresh food, or to treat insecticides, disinfection, sterilization, mildew, etc. The process of extending the preservation time, stabilizing and improving the quality of food.