Nisin treatments to control Listeria monocytogenes post-processing contamination on Anthotyros, a traditional Greek whey cheese, stored at 4°C in vacuum packages

Survival of Listeria monocytogenes in Galotyri, a traditional Greek soft acid-curd cheese, stored aerobically at 4°C and 12°C

“…More specifically, the higher the pH of the soft cheese, the greater the survival of the pathogen. In fact, L. monocytogenes not only survives but also grows in soft cheeses with a pH of 5.5 or above, such as Brie, Camembert, Mexican-/Hispanic-type and traditional whey (Ricotta, Anthotyros) cheeses (Genigeorgis et al, 1991;Back et al, 1993;Ryser, 1999b;Samelis, Kakouri, Rogga, Savvaidis, & Kontominas, 2003). In contrast, soft ripened cheeses with a pH close to 4.5 and a salt content above 2%, such as Feta cheese, do not support growth but may allow low survival of L. monocytogenes for extended periods of storage at 4 C (Papageorgiou & Marth, 1989;Genigeorgis et al, 1991).…”

Effects of Nisin and Lysozyme on Growth Inhibition and Biofilm Formation Capacity of Staphylococcus aureus Strains Isolated from Raw Milk and Cheese Samples

“…In fact, nisin and lysozyme are currently used effectively in cheeses as an alternative to nitrates to prevent late blowing caused by Clostridium tyrobutyricum (8,38). Nisin is also used in various cheese and milk products to inhibit gram-positive pathogenic bacteria, including Clostridium botulinum, Listeria monocytogenes, and Staphylococcus aureus (13,31,35,37).…”

“…Because the biofilm formed by the bacteria increases its resistance to mechanical cleaning and disinfectants, the bacteria can spread into different parts of processing environments and subsequently contaminate food (7,9). Thus, cheese from heat-treated milk and whey might also carry significant risks unless processing equipment is decontaminated effectively and unless the curd obtained postheating is handled and stored properly (21,37). Biofilm is also an important virulence factor because it protects bacteria from opsonophagocytosis and antibiotics (14,25).…”

Characterization of a Wild, Novel Nisin A-Producing Lactococcus Strain with an L. lactis subsp. cremoris Genotype and an L. lactis subsp. lactis Phenotype, Isolated from Greek Raw Milk

“…Wild antipathogenic L. lactis strains are also naturally present or have been applied as bioprotective/costarter cultures in cheese and other foods to produce bacteriocins in situ, with nisin being the commonest and best characterized (14,15,16,17). Nisin has been permitted to be used and applied as a natural generally recognized as safe (GRAS) preservative in many countries (17,18,19). In general, dairy lactococci, and L. lactis in particular, are considered safe for human health and consumption, and thus, their multiple applications in foods as well as probiotics are of continuously increasing scientific and industrial interest (2).…”