An assessment of the microbiological quality and safety of raw drinking milk on retail sale in England.

ABSTRACT

AIMS: This study aimed to review the microbiological results for raw drinking milk (RDM) samples submitted to Public Health England laboratories between 2014 and 2016 in order to produce up-to-date data on the microbiological safety of RDM and inform future risk assessments on its sale. METHODS AND RESULTS: A total of 902 samples of RDM were collected from retail sale in England for microbiological examination. Overall, 454 of 770 samples (59·0%) taken for routine monitoring were of a satisfactory quality, whilst eight (1·0%) were 'unsatisfactory and potentially injurious to health' due to the presence of Shiga toxin-producing Escherichia coli, Campylobacter or elevated levels of Listeria monocytogenes or coagulase-positive staphylococci. In contrast, 16 of 114 (14·0%) of samples taken in follow-up to a previous unsatisfactory result and 5 of 18 (27·8%) of samples related to illness were potentially injurious. A total of 229 of 902 samples (25·4%) gave unsatisfactory results due to elevated aerobic colony counts and/or coliforms, whilst 139 of 902 samples (15·4%) were of borderline quality due to coagulase-positive staphylococci. Listeria monocytogenes was detected at levels of <100 CFU per ml in 66 of 902 samples (7·3%) and other Listeria species in 44 of 902 samples (4·9%). CONCLUSIONS: Pathogens and/or indicators of poor hygiene were present in almost half of samples examined. Cows' milk samples gave a significantly greater proportion of unsatisfactory results compared to milk from other species (i.e. goat, sheep, buffalo, camel). SIGNIFICANCE AND IMPACT OF THE STUDY These results demonstrate the importance of maintaining strict controls on the production and sale of this product.