The effect of storage temperature and inoculum level on the time of onset of `blown pack' spoilage

Aims: To examine the effect of storage temperature and inoculum level on the time of onset of 'blown pack' spoilage (BPS) caused by psychrotolerant bacteria in vacuum-packed (VP) meats.Methods and Results: Gas-producing species and strains (n = 11), recovered in our laboratory or reported as associated with BPS, were inoculated onto beef or lamb meat pieces at final levels of <10, 10, 102 and 103 CFU cm22122, VP and stored at 22121·5, 1 or 4°C. Six strains produced observable amounts of gas within 42 days and a further four strains produced gas within 100 days. BPS was observed earliest in VP meats inoculated with Clostridium estertheticum ssp. estertheticum at all inoculum levels/storage temperature combinations examined. Storage temperature and inoculum level significantly affected (P < 0·001 and P < 0·05 respectively) the onset of BPS in all cases.Conclusions: Controlling contamination levels and lowering the storage temperature delay the onset of BPS.Significance and Impact of the Study: The study demonstrates the positive effects of low contamination2013low temperature as control interventions preventing/delaying BPS in VP chilled meats and identifies some of the contaminants most likely to cause BPS in chilled stored VP meat products.