Effects on the development of blown pack spoilage of the initial numbers of Clostridium estertheticum spores and Leuconostoc mesenteroides on vacuum packed beef

Beef steaks were inoculated with Clostridium estertheticum spores and Leuconostoc mesenteroides cells at all combinations of numbers of 0, 10, 100 or 1000/cm2 for each organism. After vacuum packaging the steaks were stored at 4, 1, or −1.5 °C. Pack volumes were determined by water displacement at suitable intervals. Irrespective of L. mesenteroides numbers, for packs containing meat inoculated with 0, 10, 100 or 1000 spores/cm2, 60, 16, 3 and 1 of 60 packs did not swell. The times of onset of swelling were twice as long at −1.5 as at 4 °C, but they were not affected by the inoculated numbers of L. mesenteroides. Rates of pack swelling increased with increasing storage temperature and number of spores, but decreased with increasing numbers of inoculated L. mesenteroides. Lactic acid bacteria can apparently prevent development of blown pack spoilage of vacuum packs containing meat contaminated with low numbers of C. estertheticum.