Inhibition of Listeria monocytogenes by piscicolin 126 in milk and Camembert cheese manufactured with a thermophilic starter

Abstract

A ND M. J . C OV E NT RY . 1997. The effect of bacteriocin, piscicolin 126, on the growth of Listeria monocytogenes and cheese starter bacteria was investigated in milk and in Camembert cheese manufactured from milk challenged with 10 2 cfu ml −1 L. monocytogenes. In milk incubated at 30°C, piscicolin 126 added in the range of 512-2048 AU ml , and the viable count and acid production of these starter cultures in milk were not affected by the addition of 2048 AU ml −1 piscicolin 126. Camembert cheeses made from milk challenged with L. monocytogenes and with added piscicolin 126 showed a viable count of L. monocytogenes 3-4 log units lower than those without piscicolin 126. Inactivation of piscicolin 126 by proteolytic enzymes from cheese starter bacteria and mould together with the emergence of piscicolin 126-resistant isolates was responsible for the recovery of L. monocytogenes in the cheeses during ripening.

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

“…Similar observations have been made for enteroviruses, 32 and this effect is also assumed to be responsible for deactivation of bacteriocin activity on cheese surfaces. 23 Although this effect may not be generalized for all foods and application schemes, phage stability and infectivity is an important consideration regarding its use in industrial processes.…”

“…Several studies exist on biocontrol of L. monocytogenes in Camembert-like 23,33,34 and red-smear soft cheeses. 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.…”

“…In all trials, the changes in surface pH were found typical for the ripening of white mold cheeses and red-smear cheeses, respectively. 1,[21][22][23] Addition of phage had no influence on total aerobic plate counts and cheeses that received phage were indistinguishable from the controls regarding odor, texture and general appearance, and they were overall comparable to commercially available products. 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.…”

The Continuing Story of Class IIa Bacteriocins

“…The growth of L. monocytogenes is of major concern for the dairy industry, and some attention has been given to the use of purified bacteriocins as adjuncts to cheese fermentation and in milk. Piscicolin 126 and enterocin CCM 4231 reduced the numbers of L. monocytogenes in Camembert cheese and soy milk, respectively (114,188). Other class IIa bacteriocins, such as those listed in Table 3, are also able to inhibit the growth of L. monocytogenes in foods.…”

Variations in the Membrane Fatty Acid Composition of Resistant or Susceptible Leuconostoc or Weissella Strains in the Presence or Absence of Mesenterocin 52A and Mesenterocin 52B Produced by Leuconostoc mesenteroides subsp. mesenteroides FR52

“…Some induced resistance provides cross-resistance to other bacteriocins (4, 21). Some authors have therefore concluded that resistance to a class IIa bacteriocin protects against the lethal activities of other bacteriocins of this class (6,22,27). The resistance mechanism seems to be complex.…”