Studies on Germination of Spores of Clostridial Species Capable of Causing Food Poisoning (II)

Abstract

Spores of Clostridium botulinum types A 190 undergo germination without proceeding of subsequent outgrowth in the ALB medium (5mM L-alanine, 10mM L-lactate, 60mM bicarbonate, and 100mM phosphate buffer, pH 6.7). The effects of some chemicals, including curing agents, food preservatives, and enzyme or germination inhibitors on the spore germination in this medium were studied.D-Alanine at a concentration ratie to L-alanine 1: 1 had no effect on germination but inhibited completely at the ratio 30: 1. The addition of increasing concentrations of NaCl up to 8% to the medium pregressively decreased the rate and extent of germination over a 3 hours period, but could not prevent germination of spores which were incubated for more prolonged periods. Nitrite concentratiens of less than 0.1% had little effect on the spore germination in the medium. Higher concentrations (more than 1%) reduced slightly the rate of germination but allowed germination to occur to the same extent as those obtained in the absence of NaNO2. Furthermore, nitrite-induced germination occurred with NaNO2 concentrations as high as 4% at pH 6.0. Neither of the two chelating agents, EDTA and DPA, were inhibitory to germination in any concentration used. Of the enzyme inhibitors tested, only HgCl2 and N-ethylmaleimide were inhibitory to germination. The two food preservatiyes, sodium sorbate and nitrofuryl furyl acrylamide, had no apparent effect on germination at even greater than commercially acceptable concentrations, although 1% sorbate prevented both the rate and extent of germination over a 3 hours period to some extent.