Isolation and Characterization of Listeria phages for Control of Growth of Listeria monocytogenes in Milk

Abstract

In this study, two Listeria bacteriophages, LMPI and LMP7, were isolated from chicken feces as a means of biocontrol of L. monocytogenes. Both bacteriophages had a lytic effect on L. monocytogenes ATCC 7644, 15313, 19114, and 19115. Phages LMPI and LMP7 were able to inhibit the growth of L. monocytogenes ATCC 7644 and 19114 in tryptic soy broth at 10 degrees C and 30 degrees C. Nevertheless, LMP1 was more effective than LMP7 at inhibiting L. monocytogenes ATCC 19114. On the contrary, LMP7 was more effective than LMPI at inhibiting L. monocytogenes ATCC 7644. The morphology of LMPI and LMP7 resembled that of members of the Siphoviridae family. The growth of L. monocytogenes ATCC 7644 was inhibited by both LMPI and LMP7 in milk; however, the growth of L. monocytogenes ATCC 19114 was only inhibited by LMPI at 30 degrees C. The lytic activity of bacteriophages was also evaluated at 4 degrees C in milk in order to investigate the potential use of these phages in refrigerated products. In conclusion, these two bacteriophages exhibit different host specificities and characteristics, suggesting that they can be used as a component of a phage cocktail to control L. monocytogenes in the food industry.