Studies On Detection And Identification Of Beer Spoilage Lactic Acid Bacteria Using PCR Techniques

Microbial contaminants of the brewing process cause product spoilage. The recent increase in the consumption of draft beer as opposed to pasteurized beer has made the biological control of beer spoilage microorganisms even more important. The plate count method for enumerating microbiological contamination has remained unchanged for over a century, but it requires several days before the microorganisms are detected.The PCR method compares favorably in sensitivity with the present plate count methods (which require several days) for the detection of lactic acid bacteria and with many rapid detection methods.Colony growth of Lactobacillus brevis,Lactobacillus lindneri,Lactobacillus buchneri, Lactobacillus plantarum,Pediococcus damnosus on five culture media (NBB ,MRS and self-made UBA) was compared. Furthermore, The effects of different factors ,including DNA templates and primers , on the quality and reproducibility of PCR were investigated. According to the characteristic of 16S ribosomal RNA gene (16s rDNA),a pair of universal primers were designed for beer spoilage lactic acid bacteria (LAB). Furthermore, 5 other special primers were designed based on identifying results. It was showed that all the primers acted well in accurate identification of LAB by PCR.A new method for rapid detecting beer spoilage microorganisms by PCR was developed,This method is based on the sequence of 16s rDNA, on which a pair of specific primers were designed .Using the primers , beer spoilage LAB species were detected by PCR,The sensitivity was reached to 15CFU/250mL, The pre-enrichment of samples was needed only 12-18h,The duration for beer spoilage determination by PCR (24h) was markly shorter than by conventional method (5-7d) .