Predominant enterobacteria on modified-atmosphere packaged meat and poultry

Enterobacteria on modified-atmosphere (MA) packaged meat (n = 54) and poultry (n = 32) products were enumerated, and 899 isolates were picked and ribotyped. For identification, 16S rRNA genes of representative strains were sequenced and analyzed. Altogether 54 (60%) of the samples contained enterobacteria >104 CFU/g. In 34% of the poultry samples, enterobacteria counts were >106 CFU/g suggesting that enterobacteria may contribute to spoilage of MA packaged poultry. The enterobacteria identified were predominantly Hafnia spp. (40%) and Serratia spp. (42%) with Hafnia alvei, Hafnia paralvei, Serratia fonticola, Serratia grimesii, Serratia liquefaciens, Serratia proteamaculans, and Serratia quinivorans being the species identified. In addition, 6% of the isolates were identified as Rahnella spp., 3% as Yersinia spp., and 1% as Buttiauxella spp. Percentage distributions of the predominant genera in different products showed that 89% of the Serratia spp. were from products packaged under a high-O2 MA containing CO2 (25–35%), whereas most (76%) isolates of Hafnia originated from anaerobically packaged red meat and poultry. These findings suggest that the gas mixture used for MA packaging influence the selection of enterobacteria growing on meat and poultry. ► Enterobacteria may reach high numbers on packaged, retail poultry products. ► Hafnia spp. and Serratia spp. are predominant enterobacteria on packaged meats. ► Unaerobic packaging seemed to select for Hafnia spp. on meat and poultry. ► Serratia spp. were frequent on high-O2 modified-atmosphere packaged meat.