Surveys from different parts of the world have reported that viable Mycobacterium avium subsp. paratuberculosis (MAP) can be cultured from approximately 2% of samples of retail pasteurised milk samples. Pasteurised milk is used for the production of powdered infant formula (PIF) and therefore there is a concern that MAP may also be present in these products. Several studies have previously reported the detection of MAP in PIF using PCR-based assays. However, culture-based surveys of PIF have not detected viable MAP. Here we describe a phage amplification assay coupled with PCR (page-PCR) that can rapidly detect viable MAP in PIF. The results of a small survey showed that the phage-PCR assay detected viable MAP in 13% (4/32) of PIF samples. Culture detected viable MAP in 9% (3/32) PIF samples, all of which were also phage-PCR positive. Direct IS900 PCR detected MAP DNA in 22% (7/32) of PIF samples. The presence of viable MAP in PIF indicates that MAP either survived PIF manufacturing or that post-production contamination occurred. Irrespective of the route of MAP contamination, the presence of viable MAP in PIF is a potential public health concern.

Cyprus Veterinary Services 1417 Athalassas Av Nicosia Cyprus

Department of Agricultural Sciences Biotechnology and Food Science Cyprus University of Technology Limassol Cyprus

Division of Food Sciences University of Nottingham Sutton Bonington Campus Loughborough Leicestershire LE12 5RD United Kingdom

Veterinary Research Institute Hudcova 70 621 00 Brno Czech Republic

References provided by Crossref.org

Application of the Actiphage® Assay to Detect Viable Mycobacterium avium subsp. paratuberculosis Cells in Fresh Sheep and Goat Milk and Previously Frozen Milk and In-Line Milk Filters

Phage Amplification Assay for Detection of Mycobacterial Infection: A Review

Efficiency of DNA Isolation Methods Based on Silica Columns and Magnetic Separation Tested for the Detection of Mycobacterium avium Subsp. Paratuberculosis in Milk and Faeces