Abstract:

Dilution-PCR and PCR-DGGE were used to evaluate effect of four pre-treatment methods such as freeze-thaw, ultrasonification, shake and homogenization on extraction of bacterial DNA from chilled pork in this study. After 4 days of storage at 4 ℃, chilled pork was subjected to pre-treatment by the above methods for bacterial DNA extraction followed by dilution- PCR and PCR-DGGE analyses. Results showed that four pretreatment methods results in a slight difference in bacterial DAN yield but had no notable effect on PCR-DGGE analysis. Therefore, these pretreatment methods could be chosen according to actual requirement. Sequence analysis of DGGE bands of 16S rRNA gene V3 region showed that the predominant spoilage bacterium in chilled pork was Pseudomonas and others including Acinetobacter, Brochothrix, and Serratia were also detected.

Key words: chilled pork, pre-treatment methods, bacteria, DNA extraction, PCR-DGGE