Dry‐heat Resistance of Bacillus subtilis Spores in Contact with Serum Albumin, Carbohydrates or Lipids

The apparent dry‐heat resistance of B. subtilis var. niger spores in contact with serum albumin, certain carbohydrates or lipids, was determined in an open test system. The resistance, in terms of D 160 ‐value, was significantly increased by sucrose or serum albumin and decreased by glucose or fructose. The D 160 ‐value of spores heated in contact with olive oil and triolein was about the same as that of the control spores (clean spores). The D 160 ‐value of spores in soybean oil, tricaprin or trilaurin was, however, somewhat higher than that of the control spores. The D 160 ‐value for spores heated in different lipids increased in the order: olive oil < triolein < soybean oil < tricaprin < trilaurin. The z‐value was not significantly influenced by any of the tested substances, i.e. fructose, sucrose, olive oil, soybean oil, tricaprin or trilaurin.