Freshly cooked luncheon meat in a plastic (PVDC) casing had an aerobic plate count of about 102/g. The flora was composed of approximately equal numbers ofBacillusandMicrococcusspp. Storage at 10°C for 42 d produced little increase in bacterial numbers, or changes in pH value or glucose content at either the surface or core of the luncheon meat. Storage at 25°C allowedBacillusspp. to proliferate at the surface. The inhibitory effect of salt and nitrite on the growth of heatedBacillusspores at low redox potentials probably accounts for the absence of growth within the product. Growth at the surface was accompanied by a fall in pH (6.8 to 6.2) and an increase in glucose (1.6 to 3.6 mg/g) and L(+)‐lactic acid (1.2 to 2.3 mg/g). By day 14 theBacillusspp. had been displaced by aStreptococcussp. (107/g) which remained the dominant organism until the experiment ended on day 28. The pH continued to fall from 5.7 on day 14 to 5.2 on day 28, the L(+)‐lactic acid rose to 6.1 mg/g, but the glucose remained constant at the day 7 level (3.6 mg/g). This indicates that glucose converted to lactic acid was largely replaced by hydrolysis of the starch portion of the luncheon meat mediated by amylases produced by theBacillusmicroflora. It appears that growth of theStreptococcusis dependent upon the denitrifying activities of the initialBacillusflora reducing the concentration of nitrite ion to non‐inhibitory
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