title: Possible involvement of psychrotolerant Enterobacteriaceae in blown pack spoilage of vacuum-packaged raw meats.
abstract: Recent investigations of blown pack spoilage in New Zealand chilled vacuum-packaged meats have found moderate to high numbers of Enterobacteriaceae in the spoilage flora, but no clostridia, such as C. estertheticum and C. gasigenes, that are usually associated with blown pack spoilage. This study showed that pyschrotolerant Enterobacteriaceae produced gas in a lamb homogenate model under anaerobic conditions and that these organisms could cause blown pack spoilage of vacuum-packaged chilled meats. Significant gas production was observed with the majority of the psychrotolerant Enterobacteriaceae strains tested including presumptive species of Enterobacter, Serratia, Hafnia and Rahnella. However, no gas was produced in lamb homogenates inoculated with presumptive species of Ewingella americana or Yersinia enterocolitica. Gas production was also confirmed in vacuum-packaged lamb shoulders stored at 4 degrees C for 21 days after being inoculated with individual representative Enterobacteriaceae isolates. Biochemical characterisation proved to be more useful than genotype-based typing of 16S rRNA genes for discriminating different psychrotolerant Enterobacteriaceae from naturally contaminated meat microflora.
authors.affiliation: Food Metabolism and Microbiology, AgResearch, Ruakura, Private Bag 3123, Hamilton, New Zealand. gale.brightwell@agresearch.co.nz
authors.forename: Gale
authors.initials: G
authors.lastname: Brightwell
authors.forename: Robyn
authors.initials: R
authors.lastname: Clemens
authors.forename: Shelley
authors.initials: S
authors.lastname: Urlich
authors.forename: Jackie
authors.initials: J
authors.lastname: Boerema
mesh_terms: D000693:Anaerobiosis; D000818:Animals; D004755:Enterobacteriaceae / Q000254:growth & development*; D005506:Food Contamination / Q000032:analysis*; D005516:Food Microbiology; D018857:Food Packaging / Q000379:methods*; D005519:Food Preservation / Q000379:methods*; D006801:Humans; D008460:Meat / Q000382:microbiology*; D016133:Polymerase Chain Reaction / Q000379:methods; D012150:Polymorphism, Restriction Fragment Length; D012336:RNA, Ribosomal, 16S / Q000032:analysis; D012756:Sheep; D013696:Temperature; D013997:Time Factors; D014618:Vacuum
chemical_list: D012336:RNA, Ribosomal, 16S