China is a big country in agricultural production and export, and the output of fruits and vegetables
has occupied the first place in the world since 2001. Due to the relative lag of postpartum storage and processing technology,
the fresh food decay loss in our country is very serious.
According to statistics, the current rate of fruit decay loss in China is 25%-30%. The decay loss rate of vegetables is 20%-25%,
and the loss rate of aquatic products is about 15%, while the average loss rate of agricultural products in Europe,
the United States, Japan and other developed countries is only 1.7-5%. Backward fresh-keeping technology
and serious post-production loss have become one of the important factors that restrict the development of agricultura
l product processing industry and food industry, and affect farmers’ income and market competitiveness.
Due to peeling and cutting of fruits and vegetables, the tissue structure of fruits and vegetables is damaged, juice spilt,
and tissues are injured. Therefore, respiratory action, enzyme-promoted and non-enzyme-promoted Browning and
other physiological metabolism are accelerated. A large area of surface exposure and rich nutrition provide favorable
environmental conditions for microbial infection and growth and reproduction. It is one of the main reasons for the deterioration of cut fruits and vegetables
the main way of microbial pollution of fruits and vegetables
1. Field microbial contamination: The way of field microbial infection is mainly through the use of unfermented human and
animal manure and other crude farm manure, soil and water infection, which contaminate fruits and vegetables such as Escherichia coli,
Salmonella, mold, yeast and other types of bacteria, germs and harmful microorganisms.
2. Microbial contamination in the processing of fruits and vegetables: During the peeling and cutting of fruits and vegetables,
due to the exposure of the product surface to the air, it will be contaminated by bacteria, mold, yeast and other microorganisms.
The bacterial communities on different vegetables vary greatly. For example, the main microorganisms on fresh leafy
vegetables are Pseudomonas and Erwenella, and the main microorganisms on fresh tomatoes are Flavobacteria and Pseudomonas.
In the process of fresh cut fruit and vegetable cutting, it is the main stage of microbial contamination of products.
commonly used preservation technolog
Low-temperature preservation of fruits and vegetables is mainly through low temperature to inhibit the reproduction
of microorganisms and slow down the respiration of fruits and vegetables
The chemical fresh-keeping agents used more in the storage of chemical fresh-keeping fruits and vegetables are disinfection
and fungicide, vitality pleiotrophin fresh-keeping agent, growth inhibitor, etc., according to its use method.
Can be divide into adsorption type, soaking type, fumigation type.
Biological preservation technology is to prepare some natural substances with antibacterial or bactericidal activity into
a solution of appropriate concentration. It is applie to fresh food by soaking, spraying or coating.
And then to achieve the effect of preservation
Controlled Atmosphere storage (CA), its working principle is to artificially control fruits and vegetables in low O2
and high CO2 air closed refrigeration, so that fruits and vegetables dormant, reduce the breathing intensity of
fruits and vegetables, prolong the ripening process, to achieve the purpose of preservation.
electrolytic water preservation technology
Electrolytic water has the characteristics of strong sterilization ability, wide sterilization range, no pollution, no residue,
safety for human body, convenient production, low cost, etc., and has been more and more widely used in recent years.
Electrolytic water is a fresh-keeping agent of immersion type, which achieves the purpose of preservation by soaking, spraying, etc.
Electrolytic water can kill or control pathogenic microorganisms on the surface or inside of fruits and vegetables.
It can also regulate the respiratory metabolism of fruits and vegetables after harvest.