Abstract: This study combined traditional culture methods and high-throughput sequencing methods to analyze the microbial changes in different parts of crayfish in the processing of raw materials, sand spitting,washing, cooking and finished products. Summarize The law of growth and decline of microorganisms in the processing of frozen cooked whole-limb crayfish was summarized and the key control points in the processing was determined. The results showed that the initial bacterial count of the raw material of crayfish was high, and the sand spitting process could significantly reduce the number of microbes in the gills, and the bacteria reduction rate reached 98.9%. The microorganisms in the gills and intestines of crayfish were reduced by 3 to 4 orders of magnitude during the cooking process, and the microbial content in the shrimp meat was below the detection limit. Also, the coliform bacteria and Pseudomonas could be killed completely. The high-throughput sequencing results showed that the species abundance and diversity in the raw shrimp gills and intestines were lower than those in crayfish meat. The crayfish gills were mainly Proteobacteria and the intestines was mainly Firmicutes. The species abundance and diversity of crayfish was reduced during the sand-spitting link. The key control points of microorganisms in the processing process were determined as sand spitting and cooking.

Key words: crayfish(Procambarus clarkii), microorganism, processing link, critical control point, high-throughput sequencing