Use of a Genetically Enhanced, Pediocin-Producing Starter Culture, Lactococcus lactis subsp. lactis MM217, To Control Listeria monocytogenes in Cheddar Cheese
AUTOR(ES)
Buyong, Nurliza
FONTE
American Society for Microbiology
RESUMO
Cheddar cheese was prepared with Lactococcus lactis subsp. lactis MM217, a starter culture which contains pMC117 coding for pediocin PA-1. About 75 liters of pasteurized milk (containing ca. 3.6% fat) was inoculated with strain MM217 (ca. 106 CFU per ml) and a mixture of three Listeria monocytogenes strains (ca. 103 CFU per ml). The viability of the pathogen and the activity of pediocin in the cheese were monitored at appropriate intervals throughout the manufacturing process and during ripening at 8°C for 6 months. In control cheese made with the isogenic, non-pediocin-producing starter culture L. lactis subsp. lactis MM210, the counts of the pathogen increased to about 107 CFU per g after 2 weeks of ripening and then gradually decreased to about 103 CFU per g after 6 months. In the experimental cheese made with strain MM217, the counts of L. monocytogenes decreased to 102 CFU per g within 1 week of ripening and then decreased to about 10 CFU per g within 3 months. The average titer of pediocin in the experimental cheese decreased from approximately 64,000 arbitrary units (AU) per g after 1 day to 2,000 AU per g after 6 months. No pediocin activity (<200 AU per g) was detected in the control cheese. Also, the presence of pMC117 in strain MM217 did not alter the cheese-making quality of the starter culture, as the rates of acid production, the pH values, and the levels of moisture, NaCl, and fat of the control cheese and the experimental cheese were similar. Our data revealed that pediocin-producing starter cultures have significant potential for protecting natural cheese against L. monocytogenes.
ACESSO AO ARTIGO
http://www.pubmedcentral.nih.gov/articlerender.fcgi?artid=90932Documentos Relacionados
- A Pediocin-Producing Lactobacillus plantarum Strain Inhibits Listeria monocytogenes in a Multispecies Cheese Surface Microbial Ripening Consortium
- Bacteriocinogenic Lactococcus lactis subsp. lactis DF04Mi isolated from goat milk: Application in the control of Listeria monocytogenes in fresh Minas-type goat cheese
- Divergence of Genomic Sequences between Lactococcus lactis subsp. lactis and Lactococcus lactis subsp. cremoris
- Bacteriocin-Producing Strain of Lactococcus lactis subsp. diacitilactis S50
- Atividade antimicrobiana de Lactococcus lactis subsp. lactics Lc08 produtor de Nisina Z contra Listeria monocytogenes em leite desnatado