The Effects of the Lantibiotic Haloduracin on Listeria monocytogenes in Queso Fresco

Listeria monocytogenes, a high mortality food-borne pathogen, is of great concern to products with few control measures to reduce survival and growth of contaminants, because it can grow under a wide range of conditions including at refrigeration temperatures. Hispanic-style cheeses made without starter culture, such as queso fresco, have a near-neutral pH and are historically associated with many listeriosis outbreaks. Other than good hygiene, few measures are capable of controlling L. monocytogenes in such products. The bacteriocin (anti-microbial protein) nisin is widely used as an anti-listerial in acidic products but has limited utility in neutral pH foods.  The bacteriocin haloduracin has been shown to exhibit greater stability at neutral pH than most bacteriocins including nisin. In this study, nisin was compared to haloduracin to determine inhibition of L. innocua, a non-pathogenic surrogate for L. monocytogenes, in queso fresco cheeses over three weeks of storage.