Bulk tank raw milk microbiota differs within and between farms: A moving goalpost challenging quality control

Skeie, Siv; Håland, Monica; Thorsen, Inga Marie; Narvhus, Judith; Porcellato, Davide

doi:10.3168/jds.2017-14083

Cited by 80 publications

(81 citation statements)

References 46 publications

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“…The complete removal of contaminations from the teat apex or the environment cannot be ensured by the results obtained in this study, and additional experiments are needed to compare microbiota from milk samples obtained pre- and post-milking. However, although some taxa associated with the environment, such as Bacillaceae and Pseudomonadaceae, were detected in the dataset their abundance was much lower (< 1%) than that found in milk collected from bulk farm tanks which included organisms present in cows as well as milk equipment and the farm environment 17 – 19 . Interestingly, by using this sampling regime, we obtained a microbiota that was highly dominated by two families ( Corynebacteriaceae and Staphylococcaceae ).…”

Section: Discussionmentioning

confidence: 74%

A core microbiota dominates a rich microbial diversity in the bovine udder and may indicate presence of dysbiosis

Porcellato

Meisal

Bombelli

et al. 2020

Sci Rep

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The importance of the microbiome for bovine udder health is not well explored and most of the knowledge originates from research on mastitis. Better understanding of the microbial diversity inside the healthy udder of lactating cows might help to reduce mastitis, use of antibiotics and improve animal welfare. In this study, we investigated the microbial diversity of over 400 quarter milk samples from 60 cows sampled from two farms and on two different occasions during the same lactation period. Microbiota analysis was performed using amplicon sequencing of the 16S rRNA gene and over 1000 isolates were identified using MALDI-TOF MS. We detected a high abundance of two bacterial families, Corynebacteriaceae and Staphylococcaceae, which accounted for almost 50% of the udder microbiota of healthy cows and were detected in all the cow udders and in more than 98% of quarter milk samples. A strong negative correlation between these bacterial families was detected indicating a possible competition. The overall composition of the udder microbiota was highly diverse and significantly different between cows and between quarter milk samples from the same cow. Furthermore, we introduced a novel definition of a dysbiotic quarter at individual cow level, by analyzing the milk microbiota, and a high frequency of dysbiotic quarter samples were detected distributed among the farms and the samples. These results emphasize the importance of deepening the studies of the bovine udder microbiome to elucidate its role in udder health.

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Section: Discussionmentioning

confidence: 74%

A core microbiota dominates a rich microbial diversity in the bovine udder and may indicate presence of dysbiosis

Porcellato

Meisal

Bombelli

et al. 2020

Sci Rep

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“…It was demonstrated that dairy farm environment influences milk microbiota (Vacheyrou et al, 2011;Skeie et al, 2019). For example, thermoduric sporeforming bacteria in milk can come from soil, silage, or bedding.…”

Section: Introductionmentioning

confidence: 99%

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

Gagnon

Hamelin

Fréchette

et al. 2020

Journal of Dairy Science

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The dairy farm environment influences the raw milk microbiota and consequently affects milk processing. Therefore, it is crucial to investigate farm management practices such as the bedding materials. The aim of this study was to evaluate the effect of recycled manure solids (RMS) as bedding material on bulk tank milk and microbiological implications for cheese quality. Bulk tank samples were collected from 84 dairy farms using RMS or straw bedding. The use of RMS did not influence thermophilic and mesophilic aerobic viable counts from spores. However, straw-milk samples gave higher values for mesophilic anaerobic spore-forming bacteria (0.44 log cfu/mL) than RMS-milk samples (0.17 log cfu/mL). The presence of thermoresistant lactic acid bacteria was not increased in milk from farms using RMS. Nevertheless, taxonomic profiles of thermoresistant bacteria isolated were different between the 2 types of milk. More Enterococcus faecalis and Streptococcus spp. were identified in RMS-milk samples. Thermoresistant enterococci and streptococci could easily end up in cheese. Therefore, milk proteolytic activities of these isolates were tested. Neither Streptococcus spp. nor Enterococcus faecium isolates exhibited proteolytic activities, whereas 53% of E. faecalis showed some. Also, only 1 vancomycin-resistant enterococcus was detected. Survival of selected RMS-milk samples isolates (3 E. faecalis and 1 Streptococcus thermophilus) was evaluated during a model Cheddar cheese manufacture. Although those strains survived well, they did not modify the acidification curve of milk. However, they might cause organoleptic defects during cheese maturing.

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“…Although Turicibacter was enriched in slit containing cheese produced in 2015, members of this genus were not isolated under the growth conditions used here, potentially because strict anaerobic conditions were not applied [68]. Although members of this genus have yet to be isolated from milk and only three isolates from human and mice intestinal contents are known [68], Turicibacter appear to be pervasive in milk and have been detected in proportions over 1% in numerous studies investigating the microbiota of bovine milk and dairy products [4,[69][70][71][72]. Lastly, although most of the general quality characteristics of the commercial cheeses were indistinguishable, there was a modest but significant reduction in the salt content of cheeses that developed slits.…”

Section: Discussionmentioning

confidence: 94%

Identification and confirmation of slit defect-causing bacteria in Cheddar cheese

Marco

Xue

Brooks

et al. 2020

Preprint

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Background: Spoilage microbes remain a significant economic burden for the dairy industry. Validated approaches are needed to identify microbes present in low numbers in those foods and starting ingredients prior to spoilage. Therefore, we applied a combination of propidium monoazide treatment combined with 16S rRNA gene amplicon DNA sequencing for viable cell detection, qPCR for bacterial enumeration, and laboratory culture, isolate identification, and pilot-scale cheese production to identify the causative bacterial agents of slit defects in industrially-produced Cheddar cheese. Because spoilage cannot be predicted in advance, the bacterial composition in milk was measured immediately before and after High Temperature Short Time (HTST) pasteurization over time and on multiple days and in resulting cheese blocks. Results: Milk was sampled over 10 h periods on ten days immediately before and after the final HTST pasteurization step prior to the initiation of cheese fermentations. HTST reduced the alpha-diversity of the viable, but not total, bacterial contents in milk and increased the proportions of thermoduric and endospore-forming bacterial taxa. There was a significant increase in viable bacterial cell numbers over the 10-h run times of the pasteurizer, including 68-fold higher numbers of Thermus. Between 0.22% to 10.9% of the bacteria in cheese were non-starter contaminants comprised mainly of Lactobacillus and Streptococcus, however, only Lactobacillus proportions increased during cheese aging. Lactobacillus, and Lactobacillus fermentum in particular, was also enriched in slit-containing cheeses and in the pre-HTST and post-HTST milk used to make them. Although some endospore-forming bacteria were associated with slits and could be isolated from milk and cheese, none were consistently associated with slit development. Pilot-scale cheeses developed slits when inoculated with L. fermentum, other heterofermentative lactic acid bacteria isolates, or with uncultured bacterial consortia collected from the pre-HTST or post-HTST milk, thus confirming that low abundance taxa in milk can negatively affect cheese quality. Conclusions: We identified and verified that certain low-abundance, bacterial taxa in milk are responsible for causing slit defects in Cheddar cheese. The likelihood for microorganisms in milk to cause defects could be predicted based on comparisons of the bacteria present in the pre- and post-HTST milk used for cheesemaking.

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Bulk tank raw milk microbiota differs within and between farms: A moving goalpost challenging quality control

Cited by 80 publications

References 46 publications

A core microbiota dominates a rich microbial diversity in the bovine udder and may indicate presence of dysbiosis

A core microbiota dominates a rich microbial diversity in the bovine udder and may indicate presence of dysbiosis

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

Identification and confirmation of slit defect-causing bacteria in Cheddar cheese

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