Aerobic bacterial, coliform, Escherichia coli and Staphylococcus aureus counts of raw and processed milk from selected smallholder dairy farms of Zimbabwe

Mhone, T. A.; Matope, Gift; Saidi, Petronella T.

doi:10.1016/j.ijfoodmicro.2011.08.028

Cited by 79 publications

(87 citation statements)

References 23 publications

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“…Few publications have addressed microbiological quality or the incidence of food pathogens in milk on the African market (4,16,17,20,23). Kivaria et al (16) investigated the hygienic quality of Tanzanian raw milk marketed by smallholder dairy producers and found a mean TBC of 8.2 x 106 CFU/ml in 128 samples.…”

Section: Discussionmentioning

confidence: 99%

Microbiological Quality of Milk in Tanzania: From Maasai Stable to African Consumer Table

Schoder

Maichin

Lema³

et al. 2013

Journal of Food Protection

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In Tanzania, pastoralists such as the Maasai and small urban farmers are responsible for the country's milk production, and 95% of the national milk supply is sold without regulation. This study was conducted using hygiene checklists and milk sampling to investigate milk quality and safety at various steps throughout the milk production chain. In regions of Dar es Salaam and Lake Victoria, 196 milk samples were collected: 109 samples of raw milk, 41 samples of packed or open served heat-treated products, and 46 samples of fermented products. Samples were taken from (i) the production level (pastoralists and urban farmers), (ii) the collection level (middlemen and depots), (iii) processors (dairies), and (iv) retailers (kiosks). Samples were analyzed for hygiene criteria (total bacteria, total coliforms, Escherichia coli, and coagulase-positive staphylococci) and foodborne pathogens such as Salmonella, enterohemorrhagic E. coli O157:H7, and Listeria monocytogenes. Adequate heating of milk for drinking was determined via heat labile alkaline phosphatase and lactoperoxidase analysis. Total bacterial counts indicated that only 67% (73 of 109) of raw milk samples and 46% (19 of 41) of heat-treated samples met national Tanzanian standards. Bulk milk samples taken from the traditional milking vessels of Maasai pastoralists had the lowest total bacterial counts: ≥ 1 × 10(2) CFU/ml. Foodborne pathogens such as E. coli O157:H7 and Salmonella were isolated from 10.1% (11 of 109) of raw milk samples but were not detected in heat-treated or fermented products, and 83% of heat-treated milk samples were lactoperoxidase negative, indicating overpasteurization. Coliforms were detected in 41% (17 of 41) of processed milk samples, thus indicating a high rate of recontamination. A progressive decrease in microbial quality along the milk production chain was attributed to departures from traditional methods, inadequate milk containers, long transport distances, lack of cooling, and lack of a basic understanding of hygiene.

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Section: Discussionmentioning

confidence: 99%

Microbiological Quality of Milk in Tanzania: From Maasai Stable to African Consumer Table

Schoder

Maichin

Lema³

et al. 2013

Journal of Food Protection

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“…The microbiological quality was evaluated by the methylene blue test (Association of Official Analytical Chemists, 1998); total aerobic mesophilic bacteria on Plate Count (International Commission on Microbiological Specifications for Foods, 1986); total coliforms on Violet Red Bile Lactose Agar (Mhone et al, 2011); and the somatic cell method by California Mastitis Test (CMT) using the Fossomatic electronic equipment. All determinations were performed in triplicate.…”

Section: Chemical and Microbiological Characterization Of Goat Milkmentioning

confidence: 99%

“…When inulin is added to food in low concentrations, the rheological properties and the sensory quality of the product will not be affected When choosing the appropriate method of skimming, it was taken into account that the fat content (by Gerber) (Association of Official Analytical Chemists, 1998) was not higher than 0.5 g/100 mL of milk; and lipolysis was lower than 1.82 µeq FFA (Free Fatty Acids)/mL of milk since higher values may result in unwanted tastes like stale, soapy, or bitter (Deeth, 2006). Chemical and microbiological characteristics of skim milk were determined according to the following procedures: total aerobic mesophilic bacteria in Plate Count Agar (International Commission on Microbiological Specifications for Foods, 1986); total coliforms on Violet Red Bile Lactose Agar (Mhone et al, 2011); moisture (Association of Official Analytical Chemists, 1998); carbohydrates by difference; protein determination (formol titration method) (Egan et al, 1991); fats by Gerber (Argentina, 1969); total ash; phosphorus, and calcium (Association of Official Analytical Chemists, 1998).…”

Section: Introductionmentioning

confidence: 99%

Characterization of goat milk and potentially symbiotic non-fat yogurt

Paz¹,

Oliveira²,

Kairúz³

et al. 2014

Food Sci. Technol (Campinas)

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“…These culture-based assays are still widely used by industry and target specific phenotypes, e.g., the ability to grow at or survive exposure to particular temperatures (psychrotrophs [3], mesophiles [4], and thermodurics [5]) or the capacity to produce proteases, lipases, or other enzymes (6) or species known to be human pathogens (2). Using these culture-based techniques, Vacheyrou previously examined possible routes of microbial transfer in farms supplying raw milk for Comte style cheese, revealing that the extent to which milk was contaminated varied depending on the type of barns used to house animals (2).…”

mentioning

confidence: 99%

Impacts of Seasonal Housing and Teat Preparation on Raw Milk Microbiota: a High-Throughput Sequencing Study

Doyle

Gleeson

O’Toole

et al. 2017

Appl Environ Microbiol

135

121

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In pasture-based systems, changes in dairy herd habitat due to seasonality results in the exposure of animals to different environmental niches. These niches contain distinct microbial communities that may be transferred to raw milk, with potentially important food quality and safety implications for milk producers. It is postulated that the extent to which these microorganisms are transferred could be limited by the inclusion of a teat preparation step prior to milking. High-throughput sequencing on a variety of microbial niches on farms was used to study the patterns of microbial movement through the dairy production chain and, in the process, to investigate the impact of seasonal housing and the inclusion/exclusion of a teat preparation regime on the raw milk microbiota from the same herd over two sampling periods, i.e., indoor and outdoor. Beta diversity and network analyses showed that environmental and milk microbiotas separated depending on whether they were sourced from an indoor or outdoor environment. Within these respective habitats, similarities between the milk microbiota and that of teat swab samples and, to a lesser extent, fecal samples were apparent. Indeed, SourceTracker identified the teat surface as the most significant source of contamination, with herd feces being the next most prevalent source of contamination. In milk from cows grazing outdoors, teat prep significantly increased the numbers of total bacteria present. In summary, sequence-based microbiota analysis identified possible sources of raw milk contamination and highlighted the influence of environment and farm management practices on the raw milk microbiota. IMPORTANCEThe composition of the raw milk microbiota is an important consideration from both a spoilage perspective and a food safety perspective and has implications for milk targeted for direct consumption and for downstream processing. Factors that influence contamination have been examined previously, primarily through the use of culture-based techniques. We describe here the extensive application of high-throughput DNA sequencing technologies to study the relationship between the milk production environment and the raw milk microbiota. The results show that the environment in which the herd was kept was the primary driver of the composition of the milk microbiota composition.KEYWORDS farm practices, food chain, food safety, metagenomics, microbial source tracking, raw milk microbiota T he impact of the dairy farm environment on the microbial composition of raw milk and raw milk products has been appreciated for some time (1). There are numerous niches that collectively constitute the dairy farm environment, and these harbor a vast array of microbes. The transfer of microbes from the farm environment to raw milk can be influenced be a number of factors, including farmer hygiene, husbandry practices,

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Aerobic bacterial, coliform, Escherichia coli and Staphylococcus aureus counts of raw and processed milk from selected smallholder dairy farms of Zimbabwe

Cited by 79 publications

References 23 publications

Microbiological Quality of Milk in Tanzania: From Maasai Stable to African Consumer Table

Microbiological Quality of Milk in Tanzania: From Maasai Stable to African Consumer Table

Characterization of goat milk and potentially symbiotic non-fat yogurt

Impacts of Seasonal Housing and Teat Preparation on Raw Milk Microbiota: a High-Throughput Sequencing Study

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