Potential Antibacterial Property of Cell Free Supernatant (CFS) Lactococcus Isolates from Local Goat’s Milk Against Staphylococcus Aureus, Staphylococcus Epidermis and Escherichia Coli
Food contamination by food borne pathogens is a major worry and gave a lot of problems to consumer’s health. It is needed to control of the pathogenic and spoilage bacteria especially in dairy food to guarantee are in a good quality and safety. Nowadays, a new way interaction is using beneficial bacteria as an alternative way rather using chemical additives for increasing self-life storage and enhancing safety in dairy food. Lactococcus are believed to be safe because they have been long established as the normal flora in fermented foods. The current research are looking for new strains of Lactococcus could produce excellent antibacterial substances in the creation of new cultures starter with a high biosafety in fermented food industry. This study was to isolate potential Lactococcus strains from three local goat’s farms in Selangor and using their CFS extract to determine the antibacterial activity against common food borne pathogens such as Staphylococcus aureus, Staphylococcus epidermis and Escherichia coli. From 60 isolates, only 28 of Lactococcus isolates were a pure culture and selected to antagonistic against with the pathogenic strains. Among the 28 isolates, there are only three isolates have a good ability to inhibit both pathogens which are GK3, GK5 and GK1. Isolates GK3 is the mostly exhibited with the highest clear inhibition zone of antibacterial activity against for both pathogens tested, gram positive and negative bacteria. The inhibition zone of Lactococcus GK3 against E.coli and Staphylococcus aureus in the range of 11.29mm and 11.34mm, respectively. Isolate GK5 and GK1 of Lactococcus also showed antibacterial activity against E.coli that showing the highest activity in a range between 10.00 to 11.14mm. Isolates GK5 also could inhibit highest against S.epidermis with 9.59mm inhibition zone. In conclusion, there are three potential isolates of Lactococcus showed the remarkable inhibitory effect against both gram positive and gram negative pathogenic strains. It has a potential strains as antibacterial agent which could kill or inhibit the pathogens in dairy foods. These results suggested that this study need to further to explore their antibacterial compounds which could be used as a natural biopreservatives in dairy food industry.
Keywords - Lactococcus, goat’s milk, antibacterial, Staphylococcus aureus, Staphylococcus epidermis, Escherichia coli.