Production Of Staphylococcal Enterotoxins Research Articles

Effect of Polyphenols on Inflammation Induced by Membrane Vesicles from Staphylococcus aureus.

Staphylococcus aureus, a bacterium found on human skin, produces toxins and various virulence factors that can lead to skin infections such as atopic dermatitis. These toxins and virulence factors are carried in membrane vesicles (MVs), composed of the bacterium's own cell membranes, and are expected to reach host target cells in a concentrated form, inducing inflammation. This study investigated the effects of two polyphenols, (-)-epigallocatechin gallate (EGCG) and nobiletin (NOL), on the expression of S. aureus virulence factors and the inflammation induced by MVs. The study found that EGCG alone decreased the production of Staphylococcal Enterotoxin A (SEA), while both EGCG and NOL reduced biofilm formation and the expression of virulence factor-related genes. When S. aureus was cultured in a broth supplemented with these polyphenols, the resulting MVs showed a reduction in SEA content and several cargo proteins. These MVs also exhibited decreased levels of inflammation-related gene expression in immortalized human keratinocytes. These results suggest that EGCG and NOL are expected to inhibit inflammation in the skin by altering the properties of MVs derived from S. aureus.

Screening of antibiogram, virulence factors, and biofilm production of Staphylococcus aureus and the bio-control role of some probiotics as alternative antibiotics.

Food safety is a serious challenge in the face of increasing population and diminishing resources. Staphylococcus aureus is a critical foodborne pathogen characterized by its capability to secret a diverse range of heat-resistant enterotoxins. Antibiotic usage in dairy herds resulted in the occurrence of antimicrobial resistance (AMR) patterns among bacterial species, which were consequently transmitted to humans via dairy products. Lactic acid bacteria (LAB) produce bacteriocins, which provide an excellent source of natural antimicrobials with the further advantage of being environmentally friendly and safe. Detection of multidrug resistance (MDR) S. aureus isolates in concerned samples, molecular characteristics, biofilm production, and the inhibitory role of LAB against it. Random samples of raw milk and other dairy products were analyzed for S. aureus isolation. Phenotypic and genotypic assessment of AMR was performed, in addition to detection of classical enterotoxin genes of S. aureus. Finally, evaluation of the antimicrobial action of some Lactobacillus strains against S. aureus. Incidence rates of presumptive S. aureus in raw milk, Kariesh cheese, and yogurt samples were 50%, 40%, and 60%, respectively. The highest resistance of S. aureus was to Kanamycin (100%) and Nalidixic acid (89.3%), respectively. (78.66%) of S. aureus were MDR. 11.1% of S. aureus carried mecA gene. In concern with enterotoxins genes, PCR showed that examined isolates harbored sea with a percentage of (22.2%), while sed was found in (11.1%) of isolates. Regarding biofilm production, (88.88%) of S. aureus were biofilm producers. Finally, agar well diffusion showed that Lactobacillus acidophilus had the strongest antimicrobial action against S. aureus with inhibition zone diameter ranging from 18 to 22 mm. There is a widespread prevalence of MDR S. aureus in raw milk and dairy products. Production of staphylococcal enterotoxins, as well as biofilm production are responsible for public health risks. Therefore, installing proper hygienic routines and harsh food safety policies at food chain levels is substantial.

TMT-based quantitative proteomic and scanning electron microscopy reveals biological and morphological changes of Staphylococcus aureus irradiated by electron beam

Electron beam irradiation is an efficient cold sterilization technique that has been widely utilized in food preservation. To understand the biological and morphological changes of microorganisms by electron beam irradiation, the D10 value, growth curve, and morphological characterization by scanning electron microscope (SEM) of Staphylococcus aureus were studied. Furthermore, Tandem mass tag (TMT)-based quantitative proteomic was performed to investigate the responses of Staphylococcus aureus to electron beam. The results showed that electron beam prolonged the lag phase of bacterial growth, and irradiated bacteria were more sensitive to irradiation than unirradiated bacteria. Compared to unirradiated cells, there were 53, 96, 1055, and 431 differentially expressed proteins (DEPs) detected in 1-kGy and 2-kGy irradiated cells after 0 h and 24 h incubation, respectively. Most of the DEPs involved in DNA repair were found to be up-regulated, whereas those involved in biofilm formation and staphylococcal enterotoxin production were down-regulated. No noticeable morphological changes were observed in irradiated S. aureus. These findings provided valuable information in the responses of S. aureus to electron beam irradiation, leading to a better understanding of the effects of electron beam irradiation on food pathogens.

Spa Types and Staphylococcal Enterotoxin Production of Staphylococcus aureus Isolated from Wild Boar

Little is known about the structure of S. aureus population and the enterotoxin gene content in wild boar. In 1025 nasal swabs from wild boars, 121 S. aureus isolates were identified. Staphylococcal enterotoxin (SE) genes were identified in 18 isolates (14.9%). The seb gene was found in 2 S. aureus isolates, sec in 2 isolates, the see and seh genes were found in 4 and 11 isolates, respectively. The production of SEs was evaluated in bacteria grown in microbial broth. Concentration of SEB reached 2.70 µg/ml after 24 h and 4.46 µg/ml at 48 h. SEC was produced at 952.6 ng/ml after 24 h and 7.2 µg/ml at 48 h. SEE reached 124.1 ng/ml after 24 h and 191.6 ng/ml at 48 h of culture. SEH production reached 4.36 µg/ml at 24 h and 5.42 µg/ml at 48 h of culture. Thirty-nine spa types were identified among S. aureus isolates. The most prevalent spa types were t091 and t1181, followed by t4735 and t742, t3380 and t127. Twelve new spa types, i.e., t20572‒t20583 were identified. The wild boar S. aureus population was shown to contain previously identified animal/human-associated spa types and spa types not identified in humans or animals. We also indicate that wildlife animals can be a significant reservoir of see-positive S. aureus.

First Genome-Based Characterisation and Staphylococcal Enterotoxin Production Ability of Methicillin-Susceptible and Methicillin-Resistant Staphylococcus aureus Strains Isolated from Ready-to-Eat Foods in Algiers (Algeria).

Staphylococcus aureus is a pathogenic microorganism of humans and animals, able to cause foodborne intoxication due to the production of staphylococcal enterotoxins (SEs) and to resist antibiotic treatment as in the case of methicillin-resistant S. aureus (MRSA). In this study, we performed a genomic characterisation of 12 genetically diverse S. aureus strains isolated from ready-to-eat foods in Algiers (Algeria). Moreover, their ability to produce some classical and new staphylococcal enterotoxins (SEs) was investigated. The 12 S. aureus strains resulted to belong to nine known sequence types (STs) and to the novel ST7199 and ST7200. Furthermore, S. aureus SA46 was assigned to the European clone MRSA-ST80-SCCmec-IV. The 12 strains showed a wide endowment of se and sel (staphylococcal enterotoxin-like toxin) genes (sea, seb, sed, seg, seh, sei, selj, sek, sem, sen, seo, seq, ser, selu2, selw, selx, sey, sel30; ψent1-ψent2), including variants and pseudogenes, and harboured the enterotoxin gene cluster (egc) types 1 and 5. Additionally, they produced various amounts of SEA (64.54-345.02 ng/mL), SEB (2871.28-14739.17 ng/mL), SED (322.70-398.94 ng/mL), SEH (not detectable-239.48 ng/mL), and SER (36,720.10-63,176.06 ng/mL) depending on their genotypes. The genetic determinants related to their phenotypic resistance to β-lactams (blaZ, mecA), ofloxacin (gyrA-S84L), erythromycin (ermB), lincomycin (lmrS), kanamycin (aph(3')-III, ant(6)-I), and tetracyclin (tet(L), tet(38)) were also detected. A plethora of virulence-related genes, including major virulence genes such as the tst gene, determinant for the toxic shock syndrome toxin-1, and the lukF-PV and lukS-PV genes, encoding the panton-valentine leukocidin (PVL), were present in the S. aureus strains, highlighting their pathogenic potential. Furthermore, a phylogenomic reconstruction including worldwide foodborne S. aureus showed a clear clustering based on ST and geographical origin rather than the source of isolation.

Lactic acid bacteria as biocontrol agents to reduce Staphylococcus aureus growth, enterotoxin production and virulence gene expression

The capacity of six lactic acid bacteria (LAB) strains to decrease both the growth of Staphylococcus aureus UCLM-1 and the production of staphylococcal enterotoxins growing in co-culture in sheep's milk, was evaluated. During incubation of the cultures, samples were taken to monitor LABs and Staphylococcus growth, pH, production of organic acids, presence of the staphylococcal enterotoxins A, B, C, D, and E and the expression of 11 staphylococcal genes involved in virulence and enterotoxin production. Strains Lactiplantibacillus plantarum UCLM-101 and UCLM-56 yielded the highest decreases of both Staphylococcus aureus viable cell counts and pH, followed by the strain Levilactobacillus brevis UCLM-99. Analysis of organic acids and enterotoxins production by these three strains displayed that the main acid produced was lactic acid, while enterotoxins were not detected in the co-cultures with any of them. In addition, a decrease in the expression of some staphylococcal genes was observed, which varied depending on the LAB strain and the incubation time. Results allow us to propose the use of any of these three strains as biocontrol agents in the manufacture of “free of preservatives” dairy products, to avoid the risk of staphylococcal foodborne infections.

Food safety inspection of tas kebab and salad processing line in a catering company

This study was conducted to evaluate the sufficiency of food safety practices in a catering company. The presence of some pathogenic and indicator bacteria was monitored in the samples collected from raw materials, food, food contact surfaces and workers' hands and various steps of the tas kebab (a Turkish meat stew) and salad processing lines. Bacillus cereus was found in ready-to-eat (RTE) tas kebab and RTE salad, while Listeria monocytogenes was isolated from RTE salad. Furthermore, it was observed that RTE salad contained coagulase-positive Staphylococcus aureus without staphylococcal enterotoxin production. The swab samples obtained from cutting board surfaces, knives and workers' hands contained high counts of total aerobic bacteria and some samples were contaminated with coliforms and coagulase-positive/negative staphylococci. The presence of B. cereus and L. monocytogenes in RTE foods is a serious threat to public health, especially in the catering business. Preventing the presence of toxin-producing bacteria in RTE food is a fundamental action. Also, the occurrence of L. monocytogenes in RTE salad and B. cereus in RTE tas kebab/salad samples showed insufficient cleaning/disinfection practices. As a result, hygiene practices and regular monitoring in the catering business are necessary for food safety.

Evaluation of Staphylococcus aureus growth and staphylococcal enterotoxin production in delicatessen and fine bakery products

Staphylococcal food poisoning is one of the most prevalent causes of foodborne intoxication worldwide. Sandwiches and desserts are susceptible to contamination by S. aureus due to the high proportion of manual work during their production. Our study aimed to evaluate the impact of storage conditions on staphylococcal enterotoxin production in sandwiches and buttercream puffs. Foods were inoculated with different S. aureus strains capable of producing type A, B, and C staphylococcal enterotoxins and incubated at 15, 25, and 30 °C. During the storage, samples were analysed for S. aureus counts and for staphylococcal enterotoxins. An enzyme-linked fluorescence assay was used to detect staphylococcal enterotoxins. The influence of inappropriate storage on S. aureus growth and staphylococcal enterotoxin production was evaluated. No staphylococcal enterotoxins were detected in sandwiches stored for 72 h at any of the tested temperatures. In buttercream puffs, enterotoxins type A, B, and C were detected within 24 h of storage at 25 °C.

Toxicity of combined exposure to acrylamide and Staphylococcus aureus

In the current study, the aim was to examine the toxicity of combined exposure to acrylamide and Staphylococcus aureus. We investigated the effect of staphylococcal enterotoxin A (SEA), a toxin produced by Staphylococcus aureus, on the oxidation induced DNA damaging potency of acrylamide in mouse spleen cells using an Formamidopyrimidine-DNA glycosylase-modified (FPG)-modified comet assay. Parameters like tail moment, tail length, and % tail DNA as indicators of DNA damage were significantly increased in the combined acrylamide and SEA treatment compared with SEA or acrylamide alone. Further, we examined the effects of acrylamide and its epoxide metabolite glycidamide on overall production of SEA, SEA mRNA gene expression, and on the formation of biofilm of S. aureus. Acrylamide significantly increased the SEA expression level and SEA production in S. aureus. Acrylamide also significantly increased biofilm formation in S. aureus without affecting its growth rate. Moreover, the addition of acrylamide significantly increased the expression of S. aureus virulence factors RNAIII and icaA in fetal bovine serum. Our results showed that combined exposure to acrylamide and S. aureus or its toxin enhanced their chemical and biological toxicities.

Practical Measures Including pH Adjustment and Reduction of Bacterial Contamination to Effectively Inhibit the Production of Staphylococcal Enterotoxin A in Rice Balls and Cooked Rice

Practical Measures Including pH Adjustment and Reduction of Bacterial Contamination to Effectively Inhibit the Production of Staphylococcal Enterotoxin A in Rice Balls and Cooked Rice

A mouse zoonotic virus (LCMV): A possible candidate in the causation of SIDS

Lymphocytic choriomeningitis virus (LCMV) is a ubiquitous virus carried by rodents. It causes human disease through contact with infectious mouse faeces, urine or secretions. The virus initially infects the human respiratory tract and lungs and produces typical viral symptoms and signs. The infection is usually self-limiting and recovery is the norm. A small proportion of individuals may develop aseptic meningitis. It is hypothesised that in infancy the virus may cause respiratory tract infection through contact with mouse excreta. The infection could activate production of staphylococcal enterotoxin in babies who are colonised by Staphylococcus aureus. Indeed, a mouse animal model has shown that the combination of LCMV infection and introduction of enterotoxin B produces fatal haematogenous shock. Neither agent alone is lethal.Pathological (and physiological) evidence indicates shock could be the underlying terminal event in SIDS (the observed tissue damage seen in the heart and diaphragmatic muscles, and apoptosis observed in the brain and brainstem of SIDS cases). These features are consistent with a haematogenous shock event. The epidemiology of SIDS is entirely consistent with a mouse-related viral zoonosis. Moreover, rural cases of SIDS tend to feature more often than urban cases and their occurrence would be consistent with the dynamics of mouse populations. Low socioeconomic living conditions (a major risk factor for SIDS) is consistent with prevalence of mouse populations and poor hygienic conditions, with overcrowding. Prone sleeping would facilitate aspiration or ingestion of infectious material from contaminated surfaces. and poor hygienic conditions, with overcrowding, and prone sleeping would facilitate aspiration or ingestion of infectious material from contaminated surfaces. The epidemiology and pathology of SIDS and the dynamics and ubiquity of mouse populations together with human serological data would support the hypothesis that LCMV is a potential candidate as a key factor in the causation of SIDS.

Effect of lysozyme and Chinese liquor on Staphylococcus aureus growth, microbiome, flavor profile, and the quality of dry fermented sausage

The synergistic effect of lysozyme and Chinese liquor on the inhibition of Staphylococcus aureus growth and staphylococcal enterotoxin production, as well as the effect on microbiome, flavor profile, and the quality improvement of dry fermented sausages during 18 days storage were evaluated. The result of the disc diffusion method showed that 25 μL/mL of liquor (the corresponding concentration of alcohol was 10 μL/mL) and 10 mg/mL of lysozyme had a more significant ( P < 0.05) effect on the inhibition of S. aureus than that of other concentrations. Lysozyme combined with liquor could significantly reduce (decrement of 2.8 log 10 CFU/g) the total S. aureus counts of sausages, and significantly inhibit staphylococcal enterotoxins (SEs) production. The combination treatment had the highest diversity among the four treatments. Moreover, the combination treatment promoted the formation of more volatile compounds, but the total relative content was lower than that of liquor and lysozyme treatments. There were no obvious effects on TBARS values in different treatments. The total volatile basic nitrogen in combination treated sausages was generally lower than that of other treatments. This study confirmed that the combination treatment could be an alternative to improve the safety and quality of sausages. • The synergistic effects of lysozyme and Chinese liquor were evaluated. • The combination treatment has a synergistic inhibition effect of S. aureus. • The combination treatment could increase the diversity of the bacterial community. • Liquor could contribute to the formation of volatile compounds.

Enterotoxigenic Potential of Coagulase-Negative Staphylococci from Ready-to-Eat Food.

Although coagulase-positive staphylococci are considered to be the main factor responsible for food poisoning, an increasing role for the coagulase-negative staphylococci in the production of enterotoxins has been observed in recent years. This study was conducted to assess the occurrence of genes responsible for the production of staphylococcal enterotoxins (SE), enterotoxin-like toxins (SEI) and toxic shock syndrome toxin-1 (TSST-1) in coagulase-negative staphylococci (CoNS) isolated from ready-to-eat food from bars and restaurants. One hundred and eighteen CoNS strains were tested using polymerase chain reaction (PCR) to five superantigenic toxin genes, including five different types of classical enterotoxins (sea, seb, sec, sed and see) and the toxic shock syndrome toxin-1 (tsst-1) as well as to supertoxin-like genes. PCR-positive isolates were then tested using immunoenzymatic methods (SET-RPLA, Vidas SET 2) for toxin expression. Out of 118 CoNS strains, the presence of staphylococcal enterotoxins was confirmed in 72% of them. The most frequently found enterotoxin-like genotype was ser, selu. Two of the tested strains had up to ten different enterotoxin genes in the genome at the same time. Although no production of enterotoxins was detected in the CoNS, which means that their possible role in the epidemiology of food-borne diseases is minimal, the data demonstrated that the toxigenic capacity of the CoNS should not be ignored, and that this group of microorganisms should be continuously monitored in food.

Influence of apitoxin and melittin from Apis mellifera bee on Staphylococcus aureus strains

The antibacterial activities of apitoxin, a venom produced by Apis mellifera bee, and melittin, an antimicrobial peptide from apitoxin, were tested against planktonic and biofilm states of Staphylococcus aureus methicillin-resistant (MRSA), including clinical, and enterotoxin-producing isolates. Also, the synergism of apitoxin and melittin in combination with oxacillin were evaluated as well. The induced morphological changes on S. aureus cells of both products were detected by transmission electronic microscopy (TEM). The minimum inhibitory concentration (MIC) values were 7.2 μg/mL, and 6.7 μg/mL, for apitoxin and melittin, respectively. The minimum bactericidal concentration (MBC) values were 28.7 μg/mL, and 26 μg/mL for apitoxin and melittin, respectively. The time-kill curve assays of apitoxin or melittin with oxacillin exhibited bactericidal synergism against MRSA isolates. TEM images showed cell distortion, cell disintegration with leakage of cytoplasmic content and loss of cytoplasm content. However, apitoxin and melittin did not interfere with staphylococcal enterotoxin production or release. Thus, apitoxin and melittin are potential agents against MRSA that can serve as possible models for new antibacterial drugs.

Growth prediction of two bacterial populations in co-culture with lactic acid bacteria.

The co-culture growth of Staphylococcus aureus, Escherichia coli and lactic acid bacteria starter culture in milk was quantitatively evaluated and modelled with a set of coupled differential equations originally proposed by Baranyi and Roberts and by Gimenez and Dalgaard (BR-GD model). The lactic acid bacteria starter culture showed the ability to induce an early stationary phase of both E. coli and S. aureus populations at different combination of temperature (ranging from 12 to 37 ℃) and lactic acid bacteria inocula (from approx. 103 to 106 CFU/ml). First, the prediction ability was performed only with parameters estimated from individual growth curves of E. coli, S. aureus and the lactic acid bacteria in milk (Dataset 1, 21 experiments). Subsequently, the model was extended with the average competition coefficients (E-BR-GD model) that represented quantitative relations among the populations. The prediction ability of this model was validated with the second dataset consisting of seven experiments. Results and also their statistical indices (accuracy and bias factors) showed that the E-BR-GD model improved growth prediction of all involved populations. Thus, the total root mean square error decreased from 0.457, 0.840 and 0.322 log CFU/ml (BR-GD model) to 0.290, 0.245 and 0.333 log CFU/ml (E-BR-GD) for S. aureus, E. coli and lactic acid bacteria, respectively. This approach in growth prediction of multiple competing microbial populations can be used in assessment of S. aureus and E. coli exposure from raw milk cheeses consumption and contribute to decision making in prevention of staphylococcal enterotoxin production.

Short communication: Characterization of enterotoxin-producing Staphylococcus aureus isolated from mastitic cows

Staphylococcus aureus is not only a common cause of bovine mastitis, but also an agent of food poisoning in humans. In an attempt to determine whether staphylococci causing bovine mastitis could also cause food poisoning, 60 isolates of presumed S. aureus were isolated in the period between March and August 2017 from 3,384 routine, composite, quarter milk samples of individual cows raised on 12 dairy farms in central Italy. Seventeen out of 60 isolates were confirmed as S. aureus after coagulase, thermonuclease, and biochemical tests. These isolates were analyzed by PCR for the presence of the nuc, sea, seb, sec, sed, and see genes. The positive isolates were nuc, 100% (17); sea, 35.29% (6); seb, 5.88% (1); sec, 5.88% (1); sed, 29.41% (5); and see, 47.06% (8). The isolates were also tested with 2 enzyme immunoassay diagnostic kits, one for the screening detection of the production of staphylococcal enterotoxins (SEA, SEB, SEC, SED, SEE) and one for the detection of specific enterotoxin produced by each isolate. Seven out of 17 (41.18%) were enterotoxin producers: 7 produced SEA (41.18%), 1 SEB (5.88%), 1 SEC (5.88%), 5 SED (29.41%), and 6 SEE (35.29%). To further characterize the isolates, they were analyzed by the Kirby Bauer test for susceptibility to 13 antimicrobials (ampicillin, ciprofloxacin, kanamycin, tetracycline, gentamicin, methicillin, nalidixic acid, erythromycin, amoxicillin/clavulanic acid, streptomycin, vancomycin, neomycin, and enrofloxacin), and we detected resistance to ampicillin (52.94%), nalidixic acid (70.59%), erythromycin (5.88%), and amoxicillin/clavulanic acid (17.65%). The isolates were sensitive to the main classes of antimicrobials used for the treatment of bovine subclinical mastitis. The presence of enterotoxin-producing isolates of S. aureus in bovine milk means that a temperature abuse or a breakdown in the thermal treatment of the milk could present a food safety risk, particularly if all enterotoxigenic isolates could potentially produce SEA in milk.

Comprehensive Study of the Boundaries of Enterotoxin A Production and Growth of Staphylococcus aureus at Various Temperatures and Salt Concentrations.

Staphylococcus aureus food poisoning, which is still a serious health problem worldwide, is caused by the intoxication of staphylococcal enterotoxin (SE). Among many types of SE, staphylococcal enterotoxin type A (SEA) is known to be the most responsible for S. aureus food poisoning worldwide. Several researchers have reported the modeling of growth/no growth boundaries for S. aureus with a logistic regression model. In this study, the boundaries of SEA production and S. aureus growth in broth were first performed with the logistic regression model, to evaluate the effects of environmental factors of temperature and salt. Consequently, the boundaries of SEA production and growth of S. aureus in temperature and salt concentration could be produced with the model in shaking and stationary cultures. The area where S. aureus cells would grow, but not produce SEA could be shown between the boundaries of SEA production and growth. Internal and external validations showed that the model could well describe and predict experimental results. Further, the maximum concentrations of SEA and cell population under various conditions of temperature and salt concentration were also compared between the shaking and stationary cultures. These results obtained in this study would become useful information in food industry to prevent S. aureus food poisoning outbreaks. PRACTICAL APPLICATION: Production/no production of staphylococcal enterotoxin A at various temperatures and salt concentrations in shaking and stationary cultures could be estimated well with a logistic regression model. Growth/no growth of staphylococcal cells under the same conditions was also well estimated with the model. The area where S. aureus cells would grow, but not produce SEA could be shown with the model. This present analysis would provide useful information in food industry to prevent staphylococcal food poisoning outbreaks.

米飯保存時の黄色ブドウ球菌staphylococcal enterotoxin A（SEA）産生に与えるpH及びグリシンの影響についての菌株間における比較

米飯保存時の黄色ブドウ球菌staphylococcal enterotoxin A（SEA）産生に与えるpH及びグリシンの影響についての菌株間における比較

Production of staphylococcal enterotoxins in food

Staphylococcal food poisoning results from ingestion of food contaminated with toxins produced by enterotoxigenic Staphylococcus aureus strains. Common symptoms of this intoxication include vomiting, diarrhea, and abdominal cramps. Staphylococcal enterotoxins are resistant to heat and a number of environmental factors. Certain cheeses, milk powder, and whey powder are the only foodstuffs that are being routinely examined for the presence of staphylococcal enterotoxins SEA-SEE. The newly identified enterotoxins are not included in the current examination scheme. Enterotoxin-producing staphylococci were already isolated from meat, meat products, milk, dairy products, fermented food products, vegetables, pastries and fish products. It has been demonstrated that many environmental factors associated with food processing and storage can significantly influence the level of secreted enterotoxins by S. aureus strains. Nevertheless, only a few studies on the production of staphylococcal enterotoxins were conducted in foodstuffs. Most data on their expression is based on experiments performed with a low number of S. aureus strains, and usually only SEA-SEE enterotoxins are investigated. These results inclined many authors to the conclusion that milk and dairy products are unfavorable environments for expression of staphylococcal enterotoxins. However, recent research has indicated a significant heterogeneity in the ability of enterotoxin production in milk among S. aureus strains derived from diverse sources. S. aureus strains able to secrete high levels of enterotoxins in milk and meat juice were described. This research indicates that a high number of S. aureus strains should be used for studying staphylococcal enterotoxins expression in food. It seems to be the appropriate way to assess the risk of staphylococcal food poisoning....

Effect of Glycine on Production of Staphylococcal Enterotoxin A in Cooked Rice, and Limitation of Its Organoleptic Detection

Effect of Glycine on Production of Staphylococcal Enterotoxin A in Cooked Rice, and Limitation of Its Organoleptic Detection