on the cheese and the cheese surface was de acidified listeria monocytogenes c grew well on the cheese surface in this model to levels of 10 5 10 7 cfu cm 2 in the negative controls negative control no phage applied fig2 as seen in fig2 phage p100 completely inhibited growth of lmc no listeria was detected using the quantitative plate counting method or on enrichment the detection limit using the enrichment procedure is in the order of magnitude of one listeria per 60 cm 2 this indicates that phage p100 not only inhibited growth but actually reduced listeria titers as shown in fig2 applying phage p100 to the surface of a surface ripened cheese completely prevented outgrowth of listeria monocytogenes that had been spiked into the starter culture in order to determine if phages can survive on the cheese surface in another arm of the experiment in which a high or a low dose of phage was applied to the cheese surface phage titers were determined at cmd 6 before as well as after application of phage in all samples phages had been applied at cmd 1 cmd 2 cmd 3 and cmd 4 therefore in the samples taken before the application of phage at cmd 6 phages had been present on the cheese for at least 48 hours active phages were recovered from the cheese surface at both doses fig3 the phage titers of the samples taken before application of phage at cmd 6 were lower than the samples after application of phage the increase in phage titer corresponded well with the expected increase based on the dose added i e either 1 u00d7 10 7 pfu cm 2 or 5 39.