Occurrence of coagulase‐positive <i>Staphylococci</i>, microbial indicators and physical–chemical characteristics of traditional semihard cheese produced in Brazil

This study aimed to investigate the growth and enterotoxin production of Staphylococcus aureus during the ripening and storage of Iranian ultra-filtered white cheese (IUFWC). According to the results, the addition of starter culture had significant inhibitory effects on the growth and enterotoxin production of S. aureus. Moreover, prolong survival and enterotoxin production were observed in the samples with the highest inoculum (5 log CFU/g) of S. aureus. It was concluded that proper activity of the starter culture together with the refrigeration storage of IUFWC was the key element in inhibiting the growth and enterotoxin production of S. aureus.

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“…; Viana et al . ; Bello et al . ); however, there is a lack of knowledge concerning the behaviour of S. aureus in UF cheeses.…”

Section: Introductionmentioning

confidence: 98%

Growth and enterotoxin production of Staphylococcus aureus in Iranian ultra‐filtered white cheese

Mohammadi

Hanifian

2014

Int J of Dairy Tech

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“…Soft cheeses do not undergo any treatment while ripening to ensure their safety before consumption. Staphylococci can contaminate soft cheeses by improper handling during processing, inadequate storage conditions, use of contaminated milk, or even due to the physico-chemical features of the cheese matrix, such as high pH, high water activity, and low salt concentrations, which are favorable to the growth of these microorganisms (Viana et al, 2009). Outbreaks caused by enterotoxigenic Staphylococcus strains would hardly be associated with the contamination of Minas Frescal soft cheese, as it is considered a healthy and harmless food for the Brazilian population (Silva and Souza, 2006).…”

Section: Introductionmentioning

confidence: 99%

Identification and molecular phylogeny of coagulase-negative staphylococci isolates from Minas Frescal cheese in southeastern Brazil: Superantigenic toxin production and antibiotic resistance

Nunes

Souza

Pereira

et al. 2016

Journal of Dairy Science

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Minas Frescal is a typical Brazilian fresh cheese and one of the most popular dairy products in the country. This white soft, semiskimmed, nonripened cheese with high moisture content is obtained by enzymatic coagulation of cow milk using calf rennet or coagulants, usually in industrial dairy plants, but is also manufactured in small farms. Contamination of Minas Frescal by several staphylococci has been frequently reported. Coagulase-negative staphylococci (CNS) strains are maybe the most harmful, as they are able to produce heat-stable enterotoxins with super antigenic activities in food matrices, especially in dairy products such as soft cheeses. The aim of the present study was to investigate the presence of CNS strains in Minas Frescal marketed in southeastern Brazil concerning the risk of staphylococci food poisoning by the consumption of improperly manufactured cheese and the possibility of these food matrices being a reservoir of staphylococcal resistance to antimicrobials. Ten distinct CNS strains were found in 6 cheeses from distinct brands. The most frequent species were Staphylococcus saprophyticus (40%), Staphylococcus xylosus (30%), Staphylococcus sciuri (20%), and Staphylococcus piscifermentans (10%). Three strains were identified to the Staphylococcus genera. Three major species groups composed of 3 refined clusters were grouped by phylogenetic analyses with similarities over to 90%. All CNS strains carried multiple enterotoxin genes, with high incidence of sea and seb (90 and 70%, respectively), followed by sec/see, seh/sei, and sed with intermediate incidence (60, 50, and 40%, respectively), and, finally, seg/selk/selq/selr and selu with the lowest incidence (20 and 10%, respectively). Real-time reverse transcription PCR and ELISA assays confirmed the enteroxigenic character of the CNS strains, which expressed and produced the enterotoxins in vitro. The CNS strains showed multiresistance to antimicrobial agents such as β-lactams, vancomycin, and linezolid, which have therapeutic importance in both human and veterinarian medicines. The risk of staphylococci food poisoning by the consumption of improperly manufactured Minas Frescal was emphasized, in addition to the possibility of these food matrices being a reservoir for antibiotic resistance. More effective control measures concerning the presence and typing of staphylococci in raw milk and dairy derivatives should be included to prevent the spread of pathogenic strains.

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“…Our results are similar to those reported by Viana et al . () and Mangia et al . () for cottage and Pecorino Romano cheese respectively.…”

Section: Resultsmentioning

confidence: 92%

Microbiological, Biochemical and Rheological Changes Throughout Ripening of Kurdish Cheese

Milani

Shahidi

Mortazavi

et al. 2014

Journal of Food Safety

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Kurdish cheese has been traditionally prepared from raw milk in the northeast of Iran. It is ripened in goat's skin bags. This study was conducted on microbiological diversity and physicochemical properties of Kurdish cheese during ripening (1, 20, 40 and 60 days). The results indicated that the type and counts of microorganisms were mainly influenced by ripening time. Lactic acid bacteria and Enterobacteriaceae were predominant during the first 20 days of ripening, and lactobacilli were the most common microorganisms found during ripening. The initial numbers of coliforms and E. coli decreased rapidly, whereas a gradual increase in counts of moulds and yeasts was noticed in the early days of ripening. Coliforms, Salmonella and coagulase-positive Staphylococcus spp. were undetectable in ripened cheese. The optimal time for consuming is after 60 days because the undesired biota decreased below dangerous limits. pH, moisture content and aw decreased during ripening. No significant variations were observed in protein values during ripening. The textural parameters such as hardness, chewiness and gumminess increased as ripening progressed, but springiness decreased. The level of microelements in cheese samples during maturation were in the following order Na > Ca > K > Zn > Cu.

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Occurrence of coagulase‐positive Staphylococci, microbial indicators and physical–chemical characteristics of traditional semihard cheese produced in Brazil

Cited by 14 publications

References 16 publications

Growth and enterotoxin production of Staphylococcus aureus in Iranian ultra‐filtered white cheese

Growth and enterotoxin production of Staphylococcus aureus in Iranian ultra‐filtered white cheese

Identification and molecular phylogeny of coagulase-negative staphylococci isolates from Minas Frescal cheese in southeastern Brazil: Superantigenic toxin production and antibiotic resistance

Microbiological, Biochemical and Rheological Changes Throughout Ripening of Kurdish Cheese

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