scholarly journals Effect of Scalding Temperature on Growth of Staphylococcus aureus and Formation of Staphylococcal Enterotoxin during the Production of Alpine Cheese in a Laboratory Cheesemaking Model

2020 ◽  
Vol 83 (10) ◽  
pp. 1822-1828
Author(s):  
LIVIA SCHWENDIMANN ◽  
THOMAS BERGER ◽  
HANS-ULRICH GRABER ◽  
SUSANN MEIER ◽  
JÖRG HUMMERJOHANN ◽  
...  
Keyword(s):  
Staphylococcus Aureus ◽  
Peripheral Zone ◽  
Raw Milk ◽  
Temperature Curve ◽  
Staphylococcal Enterotoxin ◽  
Production Experiment ◽  
Strain Type ◽  
Coagulase Positive Staphylococci ◽  
Cheese Production ◽  
Hard Cheese

ABSTRACT To reduce the number of cheese with potential Staphylococcus aureus contamination reaching consumers, European legislation has stipulated that all cheese must be tested for coagulase-positive staphylococci (CPS) at the point in production when numbers are expected to be highest. When CPS counts exceed 105 CFU/mL, staphylococcal enterotoxin (SE) tests must be conducted. When SE tests are positive, the cheese must be destroyed. Manufacturers of Swiss Alpine cheese are exempt from this legislation because SE formation in hard cheese is expected to be very unlikely because of the high scalding temperatures used for cheeses during production, which inactive CPS in the curd. However, this assumption has not been scientifically tested. A laboratory-scale cheese production experiment was performed in which the conditions corresponded to certain limitations in practical cheesemaking conditions such as temperature and time exposure as for production of Gruyere or Tete de Moine Swiss type cheeses. Raw milk aliquots (200 mL) were inoculated with five strains of CPS, and scalding temperatures of 46 to 56°C were used during cheese production. The temperatures applied after the curd was pressed were meant to reproduce the temperature curve in the peripheral zone of a real cheese wheel. Contrary to expectations, SE formation occurred and differed according to the scalding temperature (52 to 56°C). The differences in SE formation were more associated with strain type rather than temperature. These results indicate that the mechanisms of SE formation in cheese require further study. HIGHLIGHTS

Characterization of Staphylococcus aureus Strains Isolated from Raw Milk Utilized in Small-Scale Artisan Cheese Production

2011 ◽  
Vol 74 (8) ◽  
pp. 1353-1358 ◽  
Author(s):  
DENNIS J. D'AMICO ◽  
CATHERINE W. DONNELLY
Keyword(s):  
Staphylococcus Aureus ◽  
Antimicrobial Resistance ◽  
Phenotypic Diversity ◽  
Raw Milk ◽  
Staphylococcal Enterotoxin ◽  
Small Scale ◽  
Enterotoxin Production ◽  
Type C ◽  
Cheese Production

Staphylococcus aureus is an important agent of bacterial mastitis in milking animals and of foodborne intoxication in humans. The purpose of this study was to examine the genetic and phenotypic diversity, enterotoxigenicity, and antimicrobial resistance of S. aureus strains isolated from raw milk used for the production of artisan cheese in Vermont. Cross-tabulations revealed that the 16 ribotypes identified among the 90 milk isolates examined were typically associated with a specific animal species and that more than half of these ribotypes were unique to individual farms. In general, specific EcoRI ribotypes were commonly associated with specific phenotypical characteristics, including staphylococcal enterotoxin production or the lack thereof. Limited antimicrobial resistance was observed among the isolates, with resistance to ampicillin (12.51%) or penicillin (17.04%) most common. Two isolates of the same ribotype obtained from the same farm were resistant to oxacillin with 2% NaCl. More than half (52.22%) of isolates produced toxin, and 31 of the 32 isolates solely produced staphylococcal enterotoxin type C. Although these data demonstrate that S. aureus strains found in raw milk intended for artisan cheese manufacture are capable of enterotoxin production, staphylococcal enterotoxin C is not typically linked to foodborne illness. Because S. aureus is a common contaminant of cheese, an understanding of the ecology of this pathogen and of the antimicrobial susceptibility and toxigenicity of various strains will ultimately contribute to the development of control practices needed to enhance the safety of artisan and farmstead cheese production.

scholarly journals Quality and safety of artisan cheese produced in the serrana region of Santa Catarina

2017 ◽  
Vol 38 (2) ◽  
pp. 739 ◽  
Author(s):  
Giane Helenita Pontarolo ◽  
Fernanda Danielle Melo ◽  
Caroline Lopes Martini ◽  
Paula Wildemann ◽  
Dileta Regina Moro Alessio ◽  
...  
Keyword(s):  
Salt Content ◽  
Raw Milk ◽  
Good Manufacturing Practice ◽  
Quality And Safety ◽  
Salmonella Spp ◽  
Santa Catarina ◽  
Maturation Period ◽  
E Coli ◽  
Coagulase Positive Staphylococci ◽  
Cheese Production

The serrano artisan cheese produced from raw milk of dairy cattle is a typical product of high-altitude farms in the states of Santa Catarina and Rio Grande do Sul. However, marketing of the cheeses occurs illegally because they lack the minimum maturation period required for cheese produced from raw milk. The production of artisan cheeses is required to follow strict hygiene standards. This study aimed to test the quality and safety of cheeses that were produced in 31 farms of the Serrana region in Santa Catarina after 14 and 28 days of maturation. Coliform count was measured at 35 °C, and presence of other microorganisms such as Escherichia coli, Staphylococcus, Listeria spp., and Salmonella spp. were also tested. Fat and protein percentages, acidity, salt content, and humidity were also evaluated. Data were subjected to statistical analyses using the SAS® software. After 14 and 28 days of maturation, 74.19% (23/31) and 64.52% (20/31) of samples, respectively, showed higher numbers of coliforms at 35 °C than those permissible by law. Higher than permissible numbers of E. coli were observed in 45.16% (14/31) and 48.39% (15/31) of the samples analyzed after 14 and 28 days of maturation, respectively. Coagulase-positive staphylococci values above 103 CFU/g were observed in 54.84% (17/31) and 51.61% (16/31) of cheese samples after 14 and 28 days of maturation, respectively. Contamination with Salmonella spp. was not detected. However, Listeria monocytogenes serovar 4b was isolated in 3.23% (1/31) and 6.45% (2/31) of samples after 14 and 28 days of maturation, respectively. The results of humidity tests classified the cheese samples into three categories: low, medium, and high humidity. Semi fat cheeses were predominant in both maturation periods, although the samples were classified in thin, semi fat, and fat cheeses. The main variations in the compositions of analyzed samples occurred for salt and acidity levels. The maturation process has not proven to be effective in reducing microbiological contamination to compliance levels. Considering the heterogeneity of the analyzed cheese samples, the frequency of non-conformities with respect to microorganisms and pathogens present in the samples, this study indicates the necessity to improve the Serrano artisan cheese production system through adoption of good manufacturing practice measures.

scholarly journals Prevalence of Staphylococcus aureus and staphylococcal enterotoxins at different stages of production of raw milk cheeses - preliminary results

2013 ◽  
Vol 57 (3) ◽  
pp. 341-345 ◽  
Author(s):  
Jolanta G. Rola ◽  
Weronika Korpysa-Dzirba ◽  
Jacek Osek
Keyword(s):  
Staphylococcus Aureus ◽  
Dairy Farms ◽  
Raw Milk ◽  
Preliminary Results ◽  
Staphylococcal Enterotoxins ◽  
Potential Sources ◽  
Genes Encoding ◽  
Coagulase Positive Staphylococci ◽  
Sources Of Contamination

Abstract The aim of the study was to identify the potential sources of contamination of traditionally made cheeses during their production with Staphylococcus aureus . The samples were collected at nine dairy farms at different points of manufacturing the cheeses. Isolation and enumeration of coagulase positive staphylococci (CPS) on Baird- Parker RPF agar was conducted, and detection of staphylococcal enterotoxins (SEs) was performed using ELISA and ELFA. The genes encoding SEs were identified by PCR. CPS were isolated from 51 samples with the highest level of contamination in mature cheese up to 107 CFU g-1. No SEs were detected in tested samples; however, enterotoxic CPS strains were found.

Comparison of Antibiogram, Staphylococcal Enterotoxin Productivity, and Coagulase Genotypes among Staphylococcus aureus Isolated from Animal and Vegetable Sources in Korea

2007 ◽  
Vol 70 (11) ◽  
pp. 2541-2548 ◽  
Author(s):  
JIN SAN MOON ◽  
AE RI LEE ◽  
SEUNG HYEUP JAW ◽  
HYUN MI KANG ◽  
YI SEOK JOO ◽  
...  
Keyword(s):  
Staphylococcus Aureus ◽  
Food Poisoning ◽  
Tetracycline Resistance ◽  
Raw Milk ◽  
Staphylococcal Enterotoxin ◽  
Food Sources ◽  
Polymorphism Analysis ◽  
Antibiotic Resistant ◽  
Raw Meat ◽  
Mastitic Milk

Staphylococcal food poisoning is caused by enterotoxin-producing Staphylococcus aureus. We investigated the prevalence of such organisms in samples of bovine mastitic milk (n = 714), raw meat (n = 139), and vegetables (n = 616). We determined the degrees of relatedness of isolates as indicated by antibiogram, staphylococcal enterotoxin (SE) productivity, and coagulase gene restriction fragment length polymorphism analysis. We examined 297 S. aureus isolates and found SE production in 57 (31.8%), 4 (7.8%), and 49 (73.1%) isolates from raw milk, raw meat, and vegetables, respectively. A high proportion of the isolates obtained from milk produced more than two types of toxins (mainly SEA, SEB, and/or SEC), whereas isolates from raw meat and vegetables primarily produced SEA alone. Most isolates were sensitive to cephalothin (97.6%), gentamicin (80.8%), erythromycin (79.5%), and tetracycline (72.7%), but were resistant to penicillin (90.2%) and ampicillin (88.9%). The proportion of antibiotic-resistant isolates differed according the source of the bacteria; the milk and vegetable isolates were more resistant to penicillin and ampicillin than were the meat isolates (P < 0.05), whereas tetracycline resistance was limited to the milk and vegetables isolates. The coagulase genotypes (I to XII) varied with the source of the organism, and only a few genotypes prevailed in each source: II (42.4%) and IV (24%) types in isolates from milk, IX (35.3%) and XI (45%) from raw meat, and III (40.3%) and XII (32.8%) from vegetables. These findings suggest that remarkable differences exist in antibiogram, SE productivity, and coagulase genotypes, resulting in limited clonal transmission of S. aureus into various food sources. As enterotoxin production only occurs when S. aureus grows to high numbers, staphylococcal food poisoning can be prevented by proper refrigeration.

Staphylococcus aureus and Listeria monocytogenes in Norwegian raw milk cheese production

2011 ◽  
Vol 28 (3) ◽  
pp. 492-496 ◽  
Author(s):  
Ragnhild Aakre Jakobsen ◽  
Ragna Heggebø ◽  
Elin Bekvik Sunde ◽  
Magne Skjervheim
Keyword(s):  
Staphylococcus Aureus ◽  
Listeria Monocytogenes ◽  
Raw Milk ◽  
Raw Milk Cheese ◽  
Cheese Production

scholarly journals Determination of staphylococcal enterotoxins in cheese by immunoenzyme assays

2012 ◽  
Vol 64 (4) ◽  
pp. 1449-1454 ◽  
Author(s):  
Vesna Jankovic ◽  
Vesna Djordjevic ◽  
Brankica Lakicevic ◽  
Branka Borovic ◽  
B. Velebit ◽  
...  
Keyword(s):  
Staphylococcus Aureus ◽  
Food Poisoning ◽  
Raw Milk ◽  
Foodborne Illness ◽  
Staphylococcal Enterotoxins ◽  
Official Gazette ◽  
Microbiological Criteria ◽  
Coagulase Positive Staphylococci

Staphylococcal food poisoning is one of the most common foodborne diseases resulting from the ingestion of staphylococcal enterotoxins (SEs) preformed in foods by enterotoxigenic strains of coagulase-positive staphylococci (CPS), mainly Staphylococcus aureus. The presence of enterotoxigenic strains of coagulase-positive staphylococci in raw milk during the production process leads to the contamination of products and outbreaks of alimentary intoxication. The problem of Staphylococcus aureus in cheese remains significant on a global level. Domestic cheese contaminated with enterotoxigenic staphylococci can result in the formation of enterotoxin, which can produce foodborne illness when the product is ingested. Due to microbiological contamination, microbiological criteria are tools that can be used in assessing the safety and quality of foods. In order to avoid foodborne illness, the Serbian Regulation on General and Special Conditions for Food Hygiene (Official Gazette of RS, No. 72/10) provides microbiological criteria for staphylococcal enterotoxins in dairy products.

scholarly journals Multidrug Resistant Coagulase-Positive Staphylococcus aureus and Their Enterotoxins Detection in Traditional Cheeses Marketed in Banat Region, Romania

Antibiotics ◽  
2021 ◽  
Vol 10 (12) ◽  
pp. 1458
Author(s):  
Adriana Morar ◽  
Alexandra Ban-Cucerzan ◽  
Viorel Herman ◽  
Emil Tîrziu ◽  
Khalid Ibrahim Sallam ◽  
...  
Keyword(s):  
Staphylococcus Aureus ◽  
Antimicrobial Susceptibility ◽  
Meca Gene ◽  
Raw Milk ◽  
Multidrug Resistant ◽  
Contamination Level ◽  
Traditional Cheeses ◽  
Antimicrobial Susceptibility Profile ◽  
Vitek 2 ◽  
Coagulase Positive Staphylococci

The main objectives of the present study were to determine the occurrence of coagulase positive staphylococci (CPS) and to assess the presence and antimicrobial susceptibility profile of Staphylococcus aureus isolates in different raw milk origin (cow and sheep) traditional cheeses marketed in Banat region, Romania. Additionally, the presence of mecA gene in S. aureus isolates and the staphylococcal enterotoxins (SEs) in cheese samples were evaluated. A total of 81.6% (138/169) of the screened samples were positive for CPS. Furthermore, 35.5% (49/138) of the investigated CPS positive cheese samples were contaminated with S. aureus, with an isolation frequency of 46.6% (14/30) in caș, 33.3% (32/96) in telemea, 25% (2/8) in burduf, and 25% (1/4) in urdă assortments, respectively. From the total number of S. aureus isolates, 6.1% (3/49) harbored the mecA gene. Detectable levels of SEs were identified in 4.3% (4/94) of cheese samples with a CPS contamination level higher than 105 log CFU g−1. The expressed antimicrobial susceptibility profile of the tested cheese-origin S. aureus isolates, with the automated Vitek 2 equipment, showed resistance towards amikacin (90.1%, 10 out from 11 tested), enrofloxacin (86.2%, 25/29), ceftiofur (72.7%, 8/11), neomycin (63.6%, 7/11), benzylpenicillin (53.1%, 26/49), kanamycin (41.4%, 12/29), rifampicin (39.5%, 15/38), tetracycline (38.8%, 19/49), tilmicosin (36.4%, 4/11), clindamycin (30.6%, 15/49), ciprofloxacin (30%, 6/20), erythromycin (22.4%, 11/49), tylosin (18.2%, 2/11), oxacillin (16.3%, 8/49), linezolid (15%, 3/20), teicoplanin (15%, 3/20), fusidic acid (13.1%), imipenem (10.5%, 4/38), vancomycin (7.9%, 3/38), ampicillin (5.5%, 1/18), mupirocin (5.5%, 1/18), fosfomycin (5%, 1/20), and gentamicin (4.1%, 2/49). Twenty-four (49%) S. aureus isolates exhibited multidrug resistance. The investigation highlighted a common occurrence of multidrug-resistant S. aureus strains in the monitored cheese assortments, which can constitute a potential risk for consumers’ health.

THE ENUMERATION OF STAPHYLOCOCCUS AUREUS ON SEVERAL TELLURITE-GLYCINE MEDIA 1 2

1962 ◽  
Vol 25 (4) ◽  
pp. 124-127 ◽  
Author(s):  
T. D. Moore ◽  
F. E. Nelson
Keyword(s):  
Staphylococcus Aureus ◽  
Nitrogen Source ◽  
Yeast Extract ◽  
Raw Milk ◽  
Glycine Concentration ◽  
Pure Cultures ◽  
The Media ◽  
Coagulase Positive Staphylococci ◽  
Coagulase Positive Staphylococcus

A study of 50 coagulase-positive staphylococcus cultures on four Tellurite-glycine formulas shows some inhibition of these organisms by the media. This inhibition can be removed partially by altering and enriching the nitrogen source, increasing mannitol and yeast extract contents and lowering the glycine concentration. Tellurite formulas that showed the greatest inhibition with pure cultures behaved similarly when coagulase-positive staphylococci were determined from raw milk.

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