Influence of soft cheese technology on the growth and enterotoxin production of Staphylococcus aureus

Necidová, Lenka; Šťástková, Zora; Pospíšilová, Markéta; Janštová, B.; Strejček, Jan; Dušková, Marta; Karpíšková, Renata

doi:10.17221/131/2008-cjfs

Cited by 15 publications

(10 citation statements)

References 16 publications

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“…At temperatures below 8 °C, the growth of S. aureus was inhibited, with no growth observed at 7.5 °C and at 8 °C, growth only occurred with optimum levels of pH and a w (Valero et al 2009). Staphylococcal counts should reach approximately 10 6 cfu·g -1 to be associated with enterotoxin production (Necidova et al 2009). It is possible for S. aureus to grow slowly at a refrigeration temperature without producing enterotoxin (Roberts et al 1996).…”

Section: Discussionmentioning

confidence: 99%

Dynamics of staphylococcal enterotoxin production in model experiments simulating the fresh cheese environment

2012

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The aim of this study was to evaluate the impact of internal factors (pH, NaCl) and external factors (temperature, incubation time) on the ability of Staphylococcus aureus to grow and to produce staphylococcal enterotoxins SEA, SEB, and SEC. The fresh cheese environment was modelled in Brain Heart Infusion Broth media and food matrices (pasteurized milk from retail outlets) by internal and external factors (pH = 4.5 and 5.5, 2% NaCl, and t = 8 °C and 15 °C). The counts of enterotoxigenic strains of S. aureus at baseline, i.e. at the time of inoculation of model samples, corresponded to those encountered in the production of fresh cheeses as a result of post-pasteurization contamination. Enumeration of S. aureus was performed in accordance with EN ISO 6888-1, using agar medium. Staphylococcal enterotoxins were detected by the enzyme-linked fluorescence assay. The pH (4.5) and refrigeration temperature (8 °C) used prevented S. aureus from achieving the critical count of 10 5 cfu·ml -1 specified in Commission Regulation (EC) No. 2073/2005. The highest rates of enterotoxin production were recorded for enterotoxin A. The growth curves of S. aureus derived from model experiments were compared with the growth curve generated by a predictive microbiology program -Pathogen Modelling Program. The results of this study proved the Pathogen Modelling Program to be suitable for use in the Hazard Analysis Critical Control Points system in the process of the fresh cheese production to help manufacturers prevent the growth of S. aureus and enterotoxin production.

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Section: Discussionmentioning

confidence: 99%

Dynamics of staphylococcal enterotoxin production in model experiments simulating the fresh cheese environment

2012

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“…Milk and milk products are frequently contaminated with Staphylococcus aureus , although dairy products are rarely involved in staphylococcal food poisoning. Also, bacteria counts of 10 5 to 10 6 CFU/g.mL are required before their enterotoxins can cause food‐related poisoning (Akineden and others ; Pelisser and others ; Necidová and others ). Classically, staphylococcal enterotoxins (SEs) have been divided into 5 major serological types (SEA, SEB, SEC, SED, and SEE) on the basis of their antigenic properties (Su and Wong ), but in the last few years, many new types of SEs, that is, SEG, SEH, SEI, SEJ, SEK, SEL, SEM, SEN, SEO, SEP, SEQ, SER, and SEU have been reported (Letertre and others ; Omoe and others ; Orwin and others ).…”

Section: Introductionmentioning

confidence: 99%

Determination of Enterotoxigenic and Methicillin Resistant Staphylococcus aureus in Ice Cream

Gücükoğlu

Çadırcı

Terzi

et al. 2013

Journal of Food Science

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The aim of this study was to determine the prevalence of enterotoxigenic and methicillin-resistant Staphylococcus aureus in ice creams. After culture-based identification of isolates, the presence of 16S rRNA and nuc was confirmed by mPCR. S. aureus was identified in 18 of 56 fruity (32.1%), 4 of 32 vanilla (12.5%), and 1 of 12 chocolate (8.3%) ice creams. S. aureus was identified as 38 isolates in 23 ice cream samples by culture-based techniques, but only 35 isolates were confirmed by PCR as S. aureus. To determine the enterotoxigenic properties of PCR-confirmed S. aureus isolates, a toxin detection kit was used (SET RPLA®). Of the 12 enterotoxigenic S. aureus isolates, 9 SEB (75%), 1 SED (8.3%), 1 SEB+SED (8.3%), and 1 SEA+SEB+SED (8.3%) expressing isolates were found. The presence of enterotoxin genes (sea, seb, sed) was identified in 13 (37.1%) out of 35 isolates by the mPCR technique. In the ice cream isolates, the sea, seb, and sed genes were detected: 1 sea (7.6%), 9 seb (69.2%), 1 sed (7.6%), 1 seb+sed (7.6%), and 1 sea+seb+sed (7.6%), respectively. The sec gene was not detected in any of these isolates. One of the 35 (2.8%) S. aureus strain was mecA positive.

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“…Milk is a good substrate for S. aureus growth, and dairy products are a known source of intoxication (De Buyser and others 2001; Jorgensen and others 2005). S. aureus counts should reach approximately 10 6 cfu/g to produce enterotoxin (Pelisser and others 2009; Necidová and others 2009). Classically, staphylococcal enterotoxins (SEs) have been divided into 5 major serological types (SEA, SEB, SEC, SED, and SEE) on the basis of their antigenic properties (Su and Lee Wong 1997), but in the last few years, many new types of SEs, that is, SEG, SEH, SEI, SEJ, SEK, SEL, SEM, SEN, SEO, SEP, SEQ, SER, and SEU have been reported (Letertre and others 2003; Omoe and others 2003; Orwin and others 2003).…”

Section: Introductionmentioning

confidence: 99%

Detection of Enterotoxigenic Staphylococcus aureus in Raw Milk and Dairy Products by Multiplex PCR

Gücükoğlu¹,

Kevenk²,

Uyanik³

et al. 2012

Journal of Food Science

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The aim of this study was to investigate the prevalence of enterotoxigenic Staphylococcus aureus in 122 samples, including 60 raw milk, 32 white cheese, 10 kashar cheese, 10 butter, and 10 ice cream samples obtained from Samsun province, Turkey. In this study, S. aureus was detected in 64 samples, including raw milk (45/60; 75%), white cheese (12/32; 37.5%), kashar cheese (3/10; 30%), butter (3/10; 30%), and ice cream (1/10; 10%) samples. A total of 81 isolates were identified as S. aureus by PCR with the presence of 16S rRNA and nuc genes. The presence of genes encoding the staphylococcal enterotoxins (SEs) SEA, SEB, SEC, and SED was detected by multiplex PCR. According to the analysis, seven isolates from the raw milk samples (7/51; 13.7%) were enterotoxigenic; five of them produced SEA (5/7; 71.4%), one produced SEB (1/7; 14.2%), and one produced SEA+SEB (1/7; 14.2%). Four isolates from the white cheese samples (4/21; 19%) produced the SEA (1/4; 25%), SEC (1/4; 25%), SED (1/4; 25%), and SEA+SED (1/4; 25%) toxins. Two isolates from the kashar cheese samples (2/4; 50%) were found to be enterotoxigenic; one produced SEA (1/2; 50%) and the other produced SED (1/2; 50%). One isolate from the butter samples (1/4; 25%) showed enterotoxigenic character (SEB, 1/1; 100%). The products were found to be potentially hazardous to public health because of the fact that levels of contamination were higher than 105-106 cfu/g ml in 39% (25/64, 17 raw milk, 7 white cheese, and 1 butter) of the analyzed samples.

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Influence of soft cheese technology on the growth and enterotoxin production of Staphylococcus aureus

Cited by 15 publications

References 16 publications

Dynamics of staphylococcal enterotoxin production in model experiments simulating the fresh cheese environment

Dynamics of staphylococcal enterotoxin production in model experiments simulating the fresh cheese environment

Determination of Enterotoxigenic and Methicillin Resistant Staphylococcus aureus in Ice Cream

Detection of Enterotoxigenic Staphylococcus aureus in Raw Milk and Dairy Products by Multiplex PCR

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