A study of the effects of food components on Clostridium perfringens growth indicated that the addition of D-glucose to sodium caseinate or to isolated soy protein greatly extended the lag phase of growth. A final concentration of 10 g glucose per liter in a sodium caseinate medium containing NaCl, K2HPO4, Na2SO4, and sodium thioglycollate increased the lag time of C. perfringens strain S40 to 3.5 h compared to 2 h for the control with no glucose, Growth was determined by colony count or absorbance (650 nm) measurement, or both. Addition of Trypticase (2 g/1) or Fe++, Ca++, or Mg++ cations (1 mM) relieved the glucose inhibition. Similar inhibition by glucose was also observed when amino acids replaced sodium caseinate and the amount of cations was controlled by adding low levels or by adding EDTA. Other sugars tested did not give this inhibitory effect. The extent of the lag time varied with glucose concentration or with level of the cell inoculum. There was a direct linear relationship between the molecules of added glucose per cell and the lag time. The mechanism appears to involve competition by food proteins for cations that affect the glucose transport system (s). These data indicate a potential control or at least delay for initial growth of C. perfringens in certain fabricated protein foods.
1Paper No. 8261 Scientific Journal Series, Minnesota Agricultural Experiment Station, St. Paul, 55101.
2Present address: Food Technology Section, Canada Department of Agriculture Research Station, Kentville, Nova Scotia, Canada.