RESUMEN
Objective:To quantitatively analyze the changes of Staphylococcus aureus in different processed products of Angelicae Sinensis Radix. Method:The real-time fluorescence quantitative polymerase chain reaction method （Real-time PCR） was established to quantitatively analyze S. aureus in Angelicae Sinensis Radix decoction pieces which bought from different producing areas， different enterprises and different storage time. The fluorescence quantitative reaction system was SYBR Premix Ex Taq Ⅱ of 10 μL， each of forward primer and reverse primer （10 μmol·L-1） of 0.8 μL， template/genome DNA of 1 μL， double distilled water of 7.4 μL. The reaction conditions of the fluorescence quantitative amplification curve were pre-denaturing for 30 s at 94 ℃， denaturing for 10 s at 94 ℃， annealing for 12 s at 60 ℃， extensing for 30 s at 72 ℃， cycling 45 times， single-point detection signal at 72 ℃. The melting curve was made from 72 ℃， and the step temperature of 0.5 ℃ was kept for 15 s to collect fluorescence. According to the results of Real-time PCR， representative samples were selected from Angelicae Sinensis Radix decoction pieces for comparison between plate counting method and Real-time PCR. Result:The content of S. aureus in different processed products was sorted by rank of raw Angelicae Sinensis Radix>soil-fried Angelicae Sinensis Radix>wine-processed Angelicae Sinensis Radix. The content of S. aureus was the lowest in the samples from Weiyuan area of Gansu province by comparing with other producing areas. Compared with the retail enterprises， the content of S. aureus in raw products and wine-processed products from production and sale enterprises was lower. Different storage time had certain effect on the content of S. aureus in raw products and wine-processed products， and the content of S. aureus increased with the increase of storage time. The detection results of plate counting method were 3-4 orders of magnitude lower than that of Real-time PCR. Conclusion:The established Real-time PCR is superior to plate counting method in specificity， sensitivity， reliability and reporting period， which can provide an effective method for rapid and accurate quantitative detection of S. aureus in different processed products of Angelicae Sinensis Radix.
RESUMEN
Objective: To make quantitative analysis for the quantity of Escherichia coli in Angelicae Sinensis Radix (ASR) and its processed products. Methods: The fluorescence quantitative PCR method was established to quantitatively analyze E. coli in ASR from different processed products, different producing areas, different enterprises and different storage time. Results: The number of E. coli in different processed products was ranked as follows: ASR > ASR stir-frying with soil > ASR stir-frying with wine. And the number of E. coli in the three producing areas of ASR in Min County of Gansu Province was less than that in other producing areas. Compared with the retail enterprises, the number of E. coli in ASR and ASR stir-frying with wine was less in production and sale enterprises. Different storage time had certain effect on the number of E. coli in ASR and ASR stir-frying with wine. With the increase of storage time, the number of E. coli also increased. Plate counting method and fluorescence quantitative PCR method were carried out at the same time for some representative samples. The results showed that the results of the plate counting method were mostly negative, and the results of the fluorescence quantitative PCR were positive. Conclusion: The quantitative fluorescence PCR method established in this paper is superior to the plate counting method in specificity, sensitivity, reliability, and reporting cycle, which can provide an effective method for rapid and accurate quantitative detection of E.coli in different processed products of ASR.