Effect of a bacteriocin-producing strain of Lactobacillus paracasei on the nonstarter microflora of Cheddar cheese

In this study, the growth of chloramphenicol-resistant bacteriocin-sensitive indicator strain Lactobacillus casei DPC 2048 ^CM was evaluated in Cheddar cheese made with bacteriocin-producing Lactobacillus paracasei DPC 4715. No suppression of growth of the indicator strain was observed in the cheese during ripening, and no bacteriocin production by L. paracasei DPC 4715 was detected by the well diffusion method in cheese and cheese extracts. The bacteriocin produced by L. paracasei DPC 4715 was sensitive to chymosin and cathepsin D, and it may have been hydrolysed by the rennet used for cheese manufacture or by indigenous milk proteases.