Bacteriophage P100 for control of Listeria monocytogenes in foods: Genome sequence, bioinformatic analyses, oral toxicity study, and application

Bacteriophage biocontrol ofListeria monocytogeneson soft ripened white mold and red-smear cheeses

“…Similar observations regarding L. monocytogenes strain-specific growth differences have been reported for other cheese models and related studies. 12,13,21,22,24,27 Our data indicate that application of phage A511 is able to eradicate L. monocytogenes cells from the cheese surfaces to levels was significant better when the target cell concentration was 1 x 10 2 cfu/cm 2 or below.…”

“…Not surprisingly, the onset of growth of Listeria Scott A and CNL 103/2005 on the cheese surfaces closely reflected the changes in surface pH, which is the major limiting factor for growth of the organism in these environments. 1,12,21,22,24 Interestingly, we noted that Scott A grew significantly slower than CNL 103/2005. The latter had been isolated in 2005 from a listeriosis outbreak in Switzerland, involving white mold soft cheese.…”

“…To ensure that the cheese models set up in the laboratory properly reflect the characteristic steps during the different ripening the surface of red-smear soft cheese, 24 whereas repeated application of lower doses (2 x 10 6 pfu/cm 2 ) resulted in a reduction of 2-3 logs. Altogether, these findings again underline the important role of phage concentration for efficacy of using phage in foods.…”

“…21,22,24,[35][36][37][38] In most cases, however, not phages but "anti-Listeria cultures" or bacteriocins were used, and the different experimental setups and various types of cheeses employed make it difficult to compare these data. Important parameters which affect the results include the Listeria strain(s) and contamination levels used, type of phage or bacteriocin applied, time point of application, type of cheese, ripening conditions and packaging conditions.…”

“…In other studies, no phage resistant Listeria emerged on phage-treated ready-to-eat foods over 6 to 13 days, 31 or red-smear cheese over 3 weeks. 24 Resistance to a specific phage added to food was also not observed with Salmonella Enteritidis on fresh-cut fruit during a 7 day period, 39 or Campylobacter jejuni on chicken skin after 10 days. 40 However, some phage-insensitive Brochothrix thermosphacta emerged on pork adipose tissue 8 days after phage was added.…”