Rapid quantitative method for salmonellas in food based on MPN (most probable number) and PCR (polymerase chain reaction)

Abstract

The invention discloses a novel and rapid quantitative method for salmonellas in food and related food samples. Based on the technical principle of MPN (most probable number) and PCR (polymerase chain reaction), the method includes the steps: firstly, performing gradient dilution for the food samples; taking multi-tube diluents from each dilution degree; performing non-selective increasing bacteria for the diluents; extracting DNA (deoxyribonucleic acid) of total bacteria of increasing bacteria samples; performing amplification for the DNA by the aid of specific salmonella primers; estimating pollution load of salmonellas in original samples according to the number of amplified positive tubes under different dilution degrees. The whole detecting process can be finished within two working days, the detection process can be effectively shortened, and workload is saved as compared with a traditional MPN (most probable number) method based on plate separation and biochemical confirmation. The method is simple and convenient, easy to operate, accurate in result and particularly applicable to rapid estimation of pollution dose or bacterium carrying level of the salmonellas in samples of fresh and cold food and the like in operations such as food safety risk assessment.

Description

technical field [0001] The invention belongs to the detection field and relates to a detection method for Salmonella. Background technique [0002] Salmonella is widely distributed, and the consensus among the academic circles is that it is the type of bacteria with the highest degree of contamination in food. In the statistics of bacterial food poisoning cases around the world, the number of cases caused by Salmonella often takes the first or second place. So far, more than 2600 Salmonella serotypes have been reported worldwide. Typhoid fever, paratyphoid fever, and fever caused by Salmonella are the most common diseases in developing countries, and even lead to death in areas with poor sanitation conditions. According to reports, about 94 million cases of gastroenteritis and 155,000 deaths worldwide are caused by Salmonella each year, 85% of which are caused by food. [0003] In China, the contamination of food safety by Salmonella is equally serious. As the primary food...

AI Technical Summary

Problems solved by technology

Although this method is currently the standard method for microbial identification and judgment of arbitration results, it usually takes several days of detection time, requires a special operating environment and cumbersome steps, and the method is qualitative, which cannot achieve quantitative detection and cannot meet food safety requirements. The needs of risk assessment and other work for the quantitative detection of Salmonella in food samples

[0005] In addition, some researchers have realized the quantitative detection of Salmonella by means of immunology or fluorescent quantitative molecular biology, but the quantitative method relies on the preset standard curve. Once the detection environment, reagents, operation steps, detection samples, etc. change Can lead to bias in quantitative results

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