title: Comparative evaluation of the association among enumeration methods and production of enterotoxins in food-derived Staphylococcus aureus.
abstract: Staphylococcal food poisoning is one of the most common foodborne diseases worldwide; it results from the ingestion of staphylococcal enterotoxins (SEs) in food, mainly Staphylococcus aureus. This study investigated the statistical relationships among morphological enumerations of food-derived S. aureus and production of SEs using different methodologies. Food samples naturally contaminated with coagulase-positive S. aureus were submitted for enumeration on Baird-Parker (BP) agar, Rabbit Plasma Fibrinogen agar (RPFA), and Petrifilm Staph Express count system (STX), and the morphologically typical colonies were isolated for VIDAS and real-time (RT) PCR tests. RPFA and STX displayed better performance for the enumeration of SE-positive S. aureus when compared with BP, including higher frequencies of SE-positive isolates and better correlation indices between typical and SE-positive counts. Among all the evaluated culture media, no significant difference (P > 0.05) was shown on the frequencies of typical colonies that carried 11 individual se genes. In addition, results for SE identification between VIDAS and RT-PCR assay were unparalleled. These data will be valuable for the selection of methods for inspection of food-derived S. aureus.
authors.affiliation: National Supervision and Testing Center for Agricultural and Sideline Product Quality, Nanjing Institute of Supervision and Testing on Product Quality, Nanjing Engineering Technical Research Center for Inspection of Food Quality and Security, 168 Hongshan Rd, Nanjing, Jiangsu, People's Republic of China 210028.
authors.forename: Chi
authors.initials: C
authors.lastname: Zhang
authors.forename: Deqin
authors.initials: D
authors.lastname: Zhang
authors.forename: Jun
authors.initials: J
authors.lastname: Yang
authors.forename: Jungui
authors.initials: J
authors.lastname: Zhou
authors.forename: Qilong
authors.initials: Q
authors.lastname: Hu
authors.forename: Rui
authors.initials: R
authors.lastname: Ling
authors.forename: Mingsheng
authors.initials: M
authors.lastname: Dong
mesh_terms: D058491:Bacterial Load / Q000379:methods; D003470:Culture Media; D004269:DNA, Bacterial / Q000235:genetics / Q000302:isolation & purification; D004768:Enterotoxins / Q000032:analysis*; D005506:Food Contamination / Q000032:analysis; D005516:Food Microbiology / Q000379:methods*; D005798:Genes, Bacterial; D007202:Indicators and Reagents; D060888:Real-Time Polymerase Chain Reaction / Q000379:methods; D013202:Staphylococcal Food Poisoning; D013211:Staphylococcus aureus / Q000737:chemistry* / Q000235:genetics
chemical_list: D003470:Culture Media; D004269:DNA, Bacterial; D004768:Enterotoxins; D007202:Indicators and Reagents