Effects of Meat-curing Salts and Temperature on Production of Staphylococcal Enterotoxin B

Abstract

We investigated the effect of time, temperature, and the presence of sodium chloride, nitrates, and nitrites in the medium on the growth and production of enterotoxin B by Staphylococcus aureus. Assays by the double gel-diffusion method showed that m enterotoxin B production occurs at the beginning of the stationary phase of growth. Lowering the tanperature of incubation decreased the amount of toxin produced without affecting the total amount of growth. Increases in concentration of curing salts reduced toxin production more rapidly than cell growth. The relationship of these observations to food-poisoning outbreaks is briefly discussed.

Staphylococci: their role in fermented sausages

“…Although Staph. aureus is tolerant of low a, (Troller 1971), its growth is retarded by elevated concentrations of NaCl (Lechowich et al 1956;McLean et al 1968;Genigeorgis et al 1971a;Metaxopoulos et al 1981a, b;Hurst & Hughes 1983;Marcy et al 1985) and enterotoxin production may be inhibited (Genigeorgis & Sadler 1966;Hojvat & Jackson 1969;Genigeorgis et al 1971a, b;Minor & Marth 1972b;Smith et al 1983Smith et al , 1987. The combined effects of NaCI, a, and pH drastically affect the growth of Staph.…”

“…Nitrate has been found to affect toxin production and, in high concentrations, the growth of Staph. aureus per se (Lechowich et al 1956;McLean et al 1968;Labots 1976;Bacus & Brown 1981;Martinez et al 1986). It was found that the nitrate effect was more pronounced under anaerobic conditions in dry sausages (Lechowich et al 1956;Barber & Deibel 1972).…”

Validation of reference genes for normalization of qPCR mRNA expression levels inStaphylococcus aureusexposed to osmotic and lactic acid stress conditions encountered during food production and preservation

“…Numerous publications investigated the production of enterotoxins under stress conditions using immunological methods (Genigeorgis & Sadler, 1966;McLean et al, 1968;Troller, 1971;Domenech et al, 1992). However, these data are of limited value, as it was later shown that loss of serological recognition does not equal loss of biological/emetic activity (Bennett, 2005).…”

Factors Affecting the Production of Bacterial Food Poisoning Toxins

“…However, the sensitivity of the method used to detect enterotoxin in the latter study was low and these results, therefore, should be interpreted with caution. McLean et al (1968) could find no effect on enterotoxin B production by adding up to 1 mglml of NaNO, or 200 pglml of NaNO, to the growth medium although some decrease was obtained when these levels of nitrate and nitrite were tested in the presence of 2% of NaC1. Holbrook (unpublished) has studied the combined effect of salt and pH on enterotoxin B production by Staph.…”

“…The rate and amount of enterotoxin A and B produced under anaerobic conditions is considerably less than that produced aerobically. In aerated cultures the amount of enterotoxin B produced in BHI a t 37" was 65 pglml after incubation for <24 h, whereas in static cultures at the same temperature, 30 pglml was produced only after 10 days (McLean et al, 1968). The present author found that after incubation for 7 days at 30" the amount of enterotoxin B in static cultures was c. 10 times higher for cultures incubated in the presence of air than for cultures incubated in a 95 : 5 mixture of N, + CO,.…”