The effect of storage temperature and inoculum level on the time of onset of ‘blown pack’ spoilage

Abstract

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. 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, 10(2) and 10(3) CFU cm(-2), VP and stored at -1.5, 1 or 4 degrees 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. Controlling contamination levels and lowering the storage temperature delay the onset of BPS. The study demonstrates the positive effects of low contamination-low 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.