Plantaricin LD1 Inhibits the Growth and Biofilm Formation of Staphylococcus aureus in Milk

Abstract

Background and objectives Bacteriocins of probiotic lactic acid bacteria have been used as bio-preservatives to improve food safety and extend the storage period of some food types. This study explored the impact of plantaricin LDL, a bacteriocins purified from the potential probiotic strain, Lactobacillus plantarum LD1, on inhibiting the growth and biofilm formation of food spoilage bacteria in milk. Methods The antimicrobial and anti-biofilm activity of Plantaricin LD1 was determined against a food-borne pathogen, Staphylococcus aureus subsp. aureus ATCC 25923. The efficacy of plantaricin LD1 against S. aureus subsp. aureus ATCC 25923 was also tested in the milk. Results Plantaricin LD1 had a minimum inhibitory concentration of 79.16 µg/mL and minimum bactericidal concentration of 158.33 µg/mL against S. aureus subsp. aureus ATCC 25923. Biofilm formation of S. aureus subsp. aureus ATCC 25923 was completely inhibited in the presence of 79.16 µg/mL of plantaricin LD1. Complete loss of cell viability in milk was observed after treatment with double minimum inhibitory concentration (158.33 µg/mL) of plantaricin LD1 at 48 hrs. Conclusions Our findings illustrate the antimicrobial and anti-biofilm activity of plantaricin LD1 against S. aureus subsp. aureus ATCC 25923 in milk. These results suggest that plantaricin LD1 can be used as a natural preservative to expand the shelf-life of milk.