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Microbiological Surveillance of Raw Milk

10 April 2012

Real-time polymerase chain reaction (PCR) reduced analysis time compared to culture methods and may be a useful tool for microbiological testing on farm, according to researchers in Italy. The PCR method was more sensitive than culture methods in detecting E. coli O157 in all samples tested.

Raw milk is increasingly appreciated by consumers but can be contaminated by a variety of zoonotic pathogens, according to Dr Giulia Amagliani of the University of Urbino ‘Carol Bo’ in Italy and co-authors there and in Pesaro and Fano. In their paper to be published in the journal, Foodborne Pathogens and Disease, they write that preventive measures, such as on–farm hazard analysis critical control point (HACCP) programmes, must be applied to protect consumers.

The aim of their study was to compare a multiplex real-time polymerase chain reaction (PCR) assay with a culture–based approach in an on–farm quality assurance programme for the detection of Escherichia coli O157, Salmonella spp. and Listeria monocytogenes in bulk tank milk, in-line milk filters, manure and faeces.

Their results revealed that the real-time PCR was more sensitive in detecting E. coli O157 than the culture method in filters (48 per cent versus 4.0 per cent positive), manure (93 per cent versus 7.0 per cent positive) and faeces (60 per cent versus 4.0 per cent positive).

The two methods were equally efficient in detecting L. monocytogenes (8.0 per cent of filters), while Salmonella spp. was not detected in any sample. I

Amagliani and co-authors concluded that the real-time PCR, by reducing analysis time to two working days, may be a useful tool in the raw milk primary production setting as a rapid and user-friendly screening method.

Reference

Amagliani G., A. Petruzzelli, E. Omiccioli, F. Tonucci, M. Magnani and G. Brandi. 2012. Microbiological surveillance of a bovine raw milk farm through multiplex real–time PCR. Foodborne Pathogens and Disease. Ahead of print. doi:10.1089/fpd.2011.1041.

Further Reading

- You can view the full report (fee payable) by clicking here.


April 2012

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