The Sensitivity of PCR to the Number of Lactococcus garvieae in Different Concentrations of NaCl: FTA Technique

Abstract

The major objective of this study is to investigate the sensitivity of PCR to the number of Lactococcus garvieae (L. garvieae) in sterilized milk containing different concentrations of NaCl using FTA technique for genomic DNA extraction. This technique is a simple, rapid, precise and highly sensitive even to low count of bacterial cells in samples. The study used M17 medium to determine the number of bacterial cells, thereafter, FTA method was used for genomic DNA extraction. The results using M17 medium, indicated that the L. garvieae increased in all concentrations of NaCl during an incubation period of 24 hours, on the other hand, pH value decreased. However, the increase in bacterial count was statistically significant only on 0, 2% and 4% of NaCl concentrations. In conjunction with this, the PCR showed sensitivity to both low and high numbers of bacterial cells in the samples. Increasing bacterial numbers led to an increase in the amount of DNA extracted via FTA cards and therefore, the intensity and clarity of bands of PCR reaction was also increased. This is the first study that uses FTA technique for DNA extraction in dairy products. Using FTA cards and subjecting to PCR in quantifying the bacterial growth is a very important issue because of its direct application in the field of milk, agricultural and animal products research and development.