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ObjectiveA rapid enrichment and detection method for Escherichia coli O157∶H7 was developed by using multienzyme isothermal rapid amplification （MIRA） fluorescence method combined with metal organic frameworks immunomagnetic beads. MethodsUsing rfbE gene as the target， the primers， probes and reaction system were screened， and the specificity， sensitivity and practical application of this method were investigated. ResultsThe detection limit of Escherichia coli O157∶H7 was 1.18×105 CFU‧mL-1， and the detection limit of DNA concentration was 9 pg‧μL-1. The detection process was completed in 20 minutes. The test results of 47 strains （24 target strains and 23 non-target strains） were consistent with real-time PCR （RT-PCR）. ConclusionA method based on metal-organic framework immunomagnetic beads enrichment combined with MIRA assay is developed in this study. The method is simple， rapid and suitable for rapid enrichment and detection of Escherichia coli O157∶H7 in food.
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Objective To investigate the microbial contamination in 54 batches of commercial honey. Methods Aerobic plate colony counts for bacteria and colonies of mould and osmophilic yeasts in honey were determined according to the National Food Safety Standard. The bacteria and fungi in unqualified samples were further identified and analyzed by morphology， MALDI-TOF-MS and large subunit （LSU） rRNA gene sequence. Results Three unqualified batches were found. One batch had aerobic plate colony counts exceeding the standard， with a variety of bacteria including Bacillus sp.， Paenibacillus sp. and Brevibacillus sp. Two batches had mould counts exceeding the standard. Aspergillus sp was detected in both samples （from the same manufacturer）， and the DNA sequence homology was very high， suggesting the mould might come from the same pollution source. Conclusion There are many kinds of microbial contamination in honey. Manufacturers should strengthen the microbe control in monitoring process to avoid the repeated microbial contamination.
RESUMO
OBJECTIVE：To compare the difference of microbiological limit test and criteria of TCM decoction pieces among 43 edition of United States Pharmacopeia （USP43），10.0 edition of European Pharmacopeia （EP10.0），17 edition of Japanese Pharmacopeia （JP17）and 2020 edition of Chinese Pharmacopeia （ChP2020），and to provide refernce for the revision and improvement of microbiological standards for TCM decoction pieces in China. METHODS ：The differences in the microbial enumeration tests method （including sampling and sample preparation ，selection of bacteria and culture medium ，count of microorganisms and heat-resistant bacteria ，etc.），tests for specified microorganisms （including sample pretreatment ，enrichment， separation and identification ，etc.）and microbial related limit criteria were compared among USP 43，EP10.0，JP17 and ChP 2020. RESULTS & CONCLUSIONS ：In terms of microbiological examination of TCM decoction pieces ，USP43，EP10.0，JP17 had their own independent provisions. Chp 2020 added“general rule 1108”. In terms of inspection items ，in addition to the total aerobic bacteria count and total combined yeasts and molds count ，ChP2020 and EP 10.0 provided three methods for the inspection of control bacteria （bile-resistant Gram-negative bacteria ， Escherichia coli ， Salmonella）. On the basis ， JP17 supplemented Staphylococcus aureus test；However，USP43 added Clostridium test method and put forward the concept of objectionable microorganisms risk assessment ；ChP2020 also added a new method for counting heat-resistant bacteria. In terms of microbial limit criteria，USP43 was the most detailed in the classification of TCM decoction pieces ，which was more strict than EP 10.0 and JP 17； ChP2020 had not set up a unified limit for the inspection of control bacteria of TCM decoction pieces. ChP 2020 revised the “microbial limit standard for TCM extracts and TCM decoction pieces ”，but it was not perfect compared with the Pharmacopoeia of the United States ，Europe and Japan. It is suggested that according to the current situation of microbial contamination and control of TCM decoction pieces ，the microbial limit test and criteria of TCM related products in Pharmacopoeia should be gradually improved ，and the microbial limit level of corresponding products should be reasonably refined.