title: Detection of viable Mycobacterium avium subspecies paratuberculosis in powdered infant formula by phage-PCR and confirmed by culture.
abstract: 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.
authors.affiliation: Department of Agricultural Sciences, Biotechnology and Food Science, Cyprus University of Technology, Limassol, Cyprus. Electronic address: george.botsaris@cut.ac.cy.
authors.forename: George
authors.initials: G
authors.lastname: Botsaris
authors.affiliation: Division of Food Sciences, University of Nottingham, Sutton Bonington Campus, Loughborough, Leicestershire LE12 5RD, United Kingdom.
authors.forename: Benjamin M C
authors.initials: BM
authors.lastname: Swift
authors.affiliation: Veterinary Research Institute, Hudcova 70, 621 00 Brno, Czech Republic.
authors.forename: Iva
authors.initials: I
authors.lastname: Slana
authors.affiliation: Cyprus Veterinary Services, 1417 Athalassas Av, Nicosia, Cyprus.
authors.forename: Maria
authors.initials: M
authors.lastname: Liapi
authors.affiliation: Department of Agricultural Sciences, Biotechnology and Food Science, Cyprus University of Technology, Limassol, Cyprus.
authors.forename: Maritsa
authors.initials: M
authors.lastname: Christodoulou
authors.affiliation: Department of Agricultural Sciences, Biotechnology and Food Science, Cyprus University of Technology, Limassol, Cyprus.
authors.forename: Maria
authors.initials: M
authors.lastname: Hatzitofi
authors.affiliation: Cyprus Veterinary Services, 1417 Athalassas Av, Nicosia, Cyprus.
authors.forename: Vasiliki
authors.initials: V
authors.lastname: Christodoulou
authors.affiliation: Division of Food Sciences, University of Nottingham, Sutton Bonington Campus, Loughborough, Leicestershire LE12 5RD, United Kingdom.
authors.forename: Catherine E D
authors.initials: CE
authors.lastname: Rees
mesh_terms: D000818:Animals; D001435:Bacteriophages / Q000235:genetics; D004269:DNA, Bacterial / Q000235:genetics*; D006801:Humans; D007223:Infant; D041943:Infant Formula / Q000382:microbiology*; D007231:Infant, Newborn; D008892:Milk / Q000382:microbiology*; D016927:Mycobacterium avium subsp. paratuberculosis / Q000235:genetics / Q000302:isolation & purification*; D016133:Polymerase Chain Reaction / Q000379:methods
chemical_list: D004269:DNA, Bacterial
keywords: PCR; Paratuberculosis; Pasteurised milk; Phage; Powdered infant formula; Rapid methods