Microbial community dynamics of a blue-veined raw milk cheese from the United Kingdom

Abstract

A commercial blue-veined cheese made from unpasteurized milk was examined by conventional culturing and PCR denaturing gradient gel electrophoresis analysis of the bacterial community 16S rRNA genes using 3 primer sets, V3, V4V5, and V6V8. Genomic DNA for amplification was extracted directly from raw milk, starter culture, cheese at different stages of production, fully ripened cheese, and from the cultured cells grown on various media. The outer rind was sampled separately from the inner white core and blue veins. A diverse microbiota containing Lactococcus lactis ssp. lactis, Lactobacillus plantarum, Lactobacillus curvatus, Staphylococcus gallinarum, Staphylococcus devriesei, Microbacterium sp., Sphingobacterium sp., Mycetocola sp., Brevundimonas sp., Enterococcus faecalis, Proteus sp., and Kocuria sp. was detected in the raw milk using culturing methods, but only Lactococcus lactis ssp. lactis, Lactobacillus plantarum, and Enterococcus faecalis survived to the final cheese and were detected both in the core and the rind. Using PCR denaturing gradient gel electrophoresis analysis of the cheese process samples, Staphylococcus equorum and Enterococcus durans were found in the rind of prepiercing samples but not in the core and veins; after piercing, these species were found in all parts of the cheese but survived only in the rind when the cheese was fully ripened. Brevibacterium sp., Halomonas sp., Acinetobacter sp., Alkalibacterium sp., and Corynebacterium casei were identified only by PCR denaturing gradient gel electrophoresis and not cultured from the samples. Brevibacterium sp. was initially identified in the cheese postpiercing (core and veins), Halomonas sp. was found in the matured cheese (rind), and Acinetobacter sp., Alkalibacterium sp., and Corynebacterium casei were also found in the prepiercing samples (rind) and then found through the subsequent process stages. The work suggests that in this raw milk cheese, a limited community from the milk survive to the final cheese, with salt addition and handling contributing to the final cheese consortium.

Effect of recycled manure solids as bedding on bulk tank milk and implications for cheese microbiological quality

“…were collected ( Figure 3B). Some studies indicated that their growth can be supported on M17 medium (Renye et al, 2011;Yunita and Dodd, 2018). Therefore, we obtained thermoresistant bacteria profiles rather than thermoresistant LAB profiles.…”

The Occurrence and Dietary Exposure Assessment of Mycotoxins, Biogenic Amines, and Heavy Metals in Mould-Ripened Blue Cheeses

“…From the viewpoint of safety, aflatoxin M 1 (AFM 1 ), the hydrolysed metabolite of aflatoxin B 1 (AFB 1 ), is the only regulated mycotoxin with an established maximum concentration of 0.05 µg kg −1 in milk used within the European markets [3]. Roquefortine C (ROQ C), mycophenolic acid (MPA), penicillic acid (PA), PR toxin, andrastatin A, and penitrem A (PNA) are major mycotoxins produced in blue cheeses mainly by strains of Penicillium roqueforti [4,5]. MPA and ROQ C have been commonly determined in blue cheeses by high-performance liquid chromatography with tandem mass spectrometry (HPLC-MS/MS) [6,7].…”

Assessing the Microbial Communities in Four Different Daqus by Using PCR-DGGE, PLFA, and Biolog Analyses

“…Four unclassified bacteria were detected only in Niulanshan Daqu. (Zhang et al 2014;Yunita et al 2018), and Pediococcus was found in the strong-flavored Daqu (Zou et al 2018).…”

“…Multivariate analysis of DGGE profiles. UPGMA cluster analysis was used to examine relationships among the four Daqus (Yunita et al 2018). Comparisons by the UPGMA cluster analysis (Fig.…”