Effects of temperature, oxygen exclusion, and storage on the microbial loads and pH of packed ostrich steaks

Abstract

Ostrich steaks (96) were packed (air or vacuum) and stored at 4 _C or 10 _C. Microbiological loads (total viable counts – TVC, psychrotrophic, Enterobacteriaceae, lactic acid bacteria – LAB, Pseudomonas and fluorescent Pseudomonas) and pH values were determined at 0, 3, 6 and 9 days. High counts (8.0-10.2 log10 cfu TVC/g) were observed at day 9, possibly as a consequence of the initial high microbial load (range 4.9-5.4 log10 cfu TVC/g) and pH (average 6.7). Temperature and sampling day significantly influenced all microbial counts. Gas atmosphere had a small or negligible influence on levels of Enterobacteriaceae and LAB. For most microbial groups temperatura significantly influenced bacterial levels up to day 6 of storage, while gas atmosphere had a significant effect at days 6 and 9. Both effects (temperature and gas atmosphere) were significant factors from day 0 for fluorescent Pseudomonas. Samples vacuum-packed and stored at 4 _C showed the lowest microbial loads at day 9. Only for these samples was no sensory rejection observed at the end of the experiment. © 2006 Elsevier Ltd. All rights reserved.

Keywords: Ostrich meat; Microbial loads; Vacuum packaging; Aerobic packaging; Storage temperature; Storage time