Growth and Enterotoxin Production by Staphylococci in Genoa Salami

Abstract

Staphylococcus aureus strains 265 and 243 which produce enterotoxins A and B, respectively, were inoculated into meat being made into Genoa salami in the amount of 103, 105, and 107, cells/g. No lactic starter culture was added. Samples were taken at different stages of processing to determine the microbial populations, percentage moisture, total acidity, pH, and enterotoxin content. Staphylococcal populations varying from about 107 to 5 × 108/g were detected during tempering of the salami. Enterotoxin A was detected in surface but not in core samples of salami inoculated with 105 and 107 S. aureus 265 cells/g. However, no enterotoxin B was detected in the salami inoculated with S. aureus 243, which requires a relatively high aw for enterotoxin production. Staphylococcal counts were higher in surface samples than in core samples, attributable to the difference in oxygen, but there was no significant difference in microaerophilic lactic Kid bacteria in different portions of the salami.

Enterotoxin production byStaphylococcus aureus(A, B, C, D) during the ripening of sucuk (Turkish dry-fermented sausage)

“…Likewise, SEA and SED were detected in the 24 h raw meatball samples that were kept at 30°C and inoculated with S. aureus A and S. aureus D, respectively (Sagun et al, 2003). Our findings in this investigation were in agreement with the results of Gonzalez-Fandos et al (1999) and Sagun et al (2003) in terms of SEA, with Lee et al (1977) in terms of SEB, and with Sagun et al (2003) and Marta et al (2011) in terms of SED production.…”

“…On the 8th day of fermentation, SEA was detected in the groups that were inoculated with 10 5 and 10 7 CFU/g of A-type toxin producing strain of S. aureus but was not detected in the group inoculated at the 10 3 CFU/g level. B-type enterotoxin was not detected in any of the samples from the groups inoculated with a B-type toxin producing strain of S. aureus, even though the number grew to 10 8 CFU/g (Lee et al, 1977). In Gonzalez-Fandos et al's (1999) traditional method, chorizo dry sausages were inoculated in a study with a strain of S. aureus A at the level of 10 6 CFU/g and were fermented at 20°C and 30°C; on the second day of fermentation, SEA was detected in their chorizo sausage samples when the number of S. aureus organisms were 10 6 and 10 8 CFU/g.…”

“…The amount of SE required for the onset of food poisoning ranges from 20 ng to 1μg (Normanno et al, 2007), which corresponds to approximately 10 5 staphylococci CFU per gram of food (Barber & Deibel, 1972;Lee et al, 1977, Pullen & Genigeorgis, 1977.…”

“…S. aureus is capable of producing toxins after reaching the concentration of 10 5 CFU/g (Barber & Deibel, 1972;Lee et al, 1977;McLean et al, 1968;Pullen & Genigeorgis, 1977;Untermann & Müller, 1992). S. aureus can grow within the temperature range of 6.7-47.8°C and at a minimum a w of 0.83-0.86; however, it can produce enterotoxin within the temperature range of 10-46°C and at a a w of above 0.88 (Lotter & Lesitner, 1978).…”

“…Therefore, studies have been performed to assess the growth, survival, and toxin producing capabilities of S. aureus strains in sausage and sausage-like products over the world (Gonzalez-Fandos et al, 1999;Kaban & Kaya, 2006;Lee, Harmon, & Price, 1977;Marcy, Kraft, Olson, Walker, & Hotchkiss,1985;Metaxopoulos, Genigeorgis, Fanelli, Franti, & Cosma, 1981;Niskanen & Nurmi, 1976;Tatini, Lee, McCall, & Hill, 1976). Likewise, studies in Turkey have been carried out to investigate the growth and survival of S. aureus in traditional Turkish sucuk during the fermentation process (Ağaoğlu, 1999;Erkmen, 2009;Kaban & Kaya, 2006;Kaban, Aksu, & Kaya, 2008), but study that examined the ability of S. aureus to produce enterotoxins (i.e., A, B, C, and D types) during the fermentation process of Turkish sucuk is found in the literature.…”