Effect of Sodium Chloride and pH on the Outgrowth of Spores of Type E Clostridium botulinum at Optimal and Suboptimal Temperatures1

Abstract

SEGNER, W. P. (Continental Can Co., Inc., Chicago, Ill.), C. F. SCHMIDT, AND J. K. BOLTZ. Effect of sodium chloride and pH on the outgrowth of spores of type E Clostridium botulinum at optimal and suboptimal temperatures. Appl. Microbiol. 14:49-54. 1966.-The sodium chloride inhibition of spore outgrowth of four strains of type E Clostridium bolulinum was determined in a Trypticase-peptoneglucose (TPG) medium. At 16, 21, and 30 C, spores of three strains required 5.0% and one strain 4.5% salt for complete inhibition during 1 year of incubation. At 8 and 10 C, spores of the four strains required 4.5% salt for definite inhibition. Salt concentrations slightly lower than those providing inhibition tended to extend spore outgrowth time at low temperatures. The minimal pH permitting outgrowth of type E spore inocula was affected by the concentration of reducing compound present in the system. When either 0.02% sodium thioglycolate or 0.05% L-cysteine hydrochloride was used, outgrowth at 30 and 8 C occurred at much lower pH levels than when 0.2 % thioglycolate was added. At 30 C, spores of one strain showed outgrowth in TPG medium as low as pH 5.21 with an inoculum of 2 million spores per replicate tube. At a 10-fold higher inoculum, the same strain showed outgrowth at pH 5.03 in one of five replicate tubes. At 8 C, spore outgrowth of the four strains occurred at pH 5.9, but not at pH 5.7, in TPG medium containing L-cysteine hydrochloride.

Fortification of carrot juice with a high‐pressure‐obtained pomegranate peel extract: chemical, safety and sensorial aspects

“…In total aerobic mesophile group, the microbial reduction attained, on average, 0.4 and 0.8 log 10 CFU mL À1 for 1 and 2.5 mg PPE per mL (P < 0.01), while for total aerobic psychrophiles the microbial reductions were about 0.2 and 0.6 log 10 CFU mL À1 , respectively (P < 0.01). Despite the clear reduction of microbial loads in treated and fortified juices, further microbiological safety studies should be conducted, especially concerning the germination of spores of Clostridium botulinum type E (Segner et al, 1966). As a low-acid beverage, carrot juice can pose a risk of botulism poisoning even after pasteurisation since lower processing temperatures could not be sufficient to eliminate spores of Clostridium botulinum; temperature abuse conditions during storage could also lead to toxin production in pasteurised carrot juices (FDA, 2007).…”

ANTIMICROBIAL EFFECTS OF SODIUM AND OTHER IONS IN FOODS: A REVIEW1

“…The concentration of NaCl permitting microbial growth generally decreases as storage temperature decreases (Table ll); or, a given NaCl concentration delays microbial growth longer at lower storage temperatures (Segner et al 1966;Ohye and Christian 1967;Alford and Palumbo 1969;Emodi and Lechowich 1969;Baird-Parker and Baillie 1973;Ingram 1973;Hauschild 1982). Pivnick and Barnett (1965) reported that with (1966) 2.2% NaCl in bologna, C. botulinum toxin was not produced for two months at 20°C or one month at 25"C, while the samples were toxic in one week at 30°C.…”

(Symposium on Bacterial Spores: Paper VI). Arrest of Growth from Spores in Semi‐preserved Foods

“…botulinum types A and B : however, type E is inhibited by 6 5 % of salt (Spencer, 1967). It has also been shown that salt concentrations which have no effect on spore outgrowth a t temperatures near optimum can extend the outgrowth time significantly a t low temperatures (Segner, Schmidt, & Boltz, 1966;Emodi & Lechowich, 1969). This fact is undoubtedly important for semi-preserved meats that require refrigeration in order to maintain product stability.…”