Behavior and Enterotoxin Production by Coagulase Negative Staphylococcus in Cooked Ham, Reconstituted Skimmed Milk, and Confectionery Cream

Abstract

In this study, the behavior and enterotoxin production by 10 different coagulase negative Staphylococcus (CNS) strains inoculated in cooked ham, reconstituted skimmed milk, and confectionery cream in the presence or absence of background microbiota have been investigated. After inoculation (103 CFU/g), foods were incubated at 25, 30, and 37 °C and aerobic mesophilic and CNS counts were carried out at 12, 24, 48, and 72 h. Staphylococcal enterotoxins (SE) detection was performed by SET-RPLA (Oxoid, Basingstoke, U.K.) and mini-Vidas® (bioMérieux, La Balme les Grottes, France). CNS counts increased during incubation and approached 10⁶ to 10⁷ CFU/g after 12 h at 37 °C in the 3 foods studied. At 25 °C, counts reached 10⁶ to 10⁷ CFU/g only after 24 to 48 h. The interference of background microbiota on CNS behavior was only observed when they grew in sliced cooked ham, which presented a high initial total count (10⁵ CFU/g). Significantly higher counts of CNS isolated from raw cow's milk in comparison with food handlers isolates were found in reconstituted milk and confectionery cream. Although CNS strains were able to produce SEA, SEB, and SED in culture media, in foods, in the presence or absence of background microbiota S. chromogenes LE0598 was the only strain able to produce SEs. Despite the scarcity of reports on CNS involvement with foodborne disease outbreaks, the results found here support the CNS growth and SE production in foods even in the presence of background microbiota and may affect food safety.

Microbiological quality and safety of minimally processed vegetables marketed in Campinas, SP – Brazil, as assessed by traditional and alternative methods

“…The counts of these microorganisms were always below the limit of quantification of the method used (10 1 CFU/g). The fact that most of studies on microbiological quality of MPV have not studied the populations and presence of coagulase positive Staphylococcus may be explained by their relative weak competition ability over the common microbiota of these products and by the fact that the production of enterotoxins does not take place below 10 C (Oliveira, Miya, Sant'Ana, & Pereira, 2010).…”

Evaluation of the microbiological quality of minimally processed vegetables

“…However, according to the results obtained, the intrinsic conditions of the fruit and the environmental conditions did not favor the establishment of this bacteria. Ot is worth mentioning that most studies on minimally processed vegetables did not study the presence of coagulase positive Staphylococcus because the production of enterotoxins does not occur at temperatures below 10 °C (Dliveira et al, 2010a). Estimated values.…”

Characterization of physicochemical composition, microbiology, sensory evaluation and microscopical attributes of sweetened condensed milk

“…These results attest to the demand for more controls during the cleaning of the plant. Some preliminary work reported that some strains of either positive and negative coagulase staphylococcus are able to produce enterotoxins in food (Rall et al, 2010;Dliveira et al, 2010;Udo et al, 1999), which indicates that Staphylococcus spp. should be considered as an indicative of microbiological risk in SCM production.…”