Research on Microbial Contamination of 14 Kinds of Mold-prone TCM Decoction Pieces and the Diversity of Fungi on the Surface
OBJECTIVE To evaluate the microbial contamination levels of 14 kinds of mold-prone TCM decoction pieces and the diversity of fungi on the surface.METHODS The total aerobic microbial count(TAMC),total yeasts and molds count(TYMC),heat-resistant microbial count(HRMC),and three types of control bacteria of mold-prone TCM decoction pieces were analyzed by referring the Chinese Pharmacopoeia 2020 Edition Volume Ⅳ 1108 microbiological limit test method.Furthermore,the fungi on the surface were cultivated using the plate method,and the single strain was isolated by the top purification method,which was further identified by colony morphology and molecular identification.RESULTS The results showed that TAMC of sample ranged 250-2.45 × 106 cfu·g-1,TYMC ranged 5-6.6 × 105 cfu·g-1,and HRMC ranged 0-30 cfu·g-1.The remaining samples of cholesterol-resistant progestin-negative bacteria did not reach 1 × 104 cfu·g-1,with the exception of one batch of Polygalae Radix and one batch of Glycyrrhizae Radix et Rhizoma.Although only one batch of Citri Reticulatae Pericarpi-um tested Escherichia coli and no Salmonella was detected in all samples,significant conditional pathogenic bacteria such as Enterobacter cloacae,Klebsiella pneumoniae,and Cronobacter sakazakii were found in the control bacterial examination items.ITS sequence sequencing comparison identified 106 strains in total,grouped into 16 genera,with Aspergillus,Penicillium,and Cladosporium accounting for 31％,18％,and 17％,respectively,of the major bacteria.Among the genus Aspergillus,11 strains of A.niger,7 strains of A.flavus,2 strains of A.fumigatus,and 1 strain of A.miscellaneous were isolated as pathogenic fungi.CONCLUSION It can provide early risk warning for its potential fungi toxins contamination through research on microbial pollution and surface fungi diversity.
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