Coagulase-positive Staphylococci Counts Research Articles

Avaliação microbiológica de carne bovina comercializadas no Brasil e conhecimentos de consumidores sobre segurança de alimentos

Meat is highly perishable and is often associated with foodborne disease outbreaks. The risk associated with handling food at home is underestimated, as consumers generally associate foodborne disease outbreaks with food from food services. This study aimed to quantify Escherichia coli, coagulase-positive staphylococci, mesophilic aerobic bacteria, and Salmonella spp. in ground beef samples sold at commercial establishments in Pelotas, Rio Grande do Sul State, Brazil, and to evaluate the knowledge of food safety among consumers in the region. Microbiological analyses were performed on 70 ground beef samples, and the knowledge of 92 meat consumers was analyzed using an online questionnaire based on the World Health Organization (WHO) safe food guidelines. Fifty percent of the meat samples had aerobic mesophilic microorganism counts above the limit established by Brazilian legislation, indicating unacceptable food quality. Only two samples (2.86%) had counts of coagulase-positive staphylococci above those allowed by legislation. The consumer knowledge regarding food safety showed that items related to “cook thoroughly” and “keeping food at safe temperatures” had the lowest percentage of correct answers. Dissemination of information about temperatures that ensure food safety is essential for consumers, especially considering that even with high levels of contamination, most microorganisms are destroyed by heat.

Occurrence, antimicrobial susceptibility, and resistance genes of Staphylococcus aureus in milk and milk products in the Arsi highlands of Ethiopia.

In Ethiopia, milk production and handling practices often lack proper hygiene measures, leading to the potential contamination of milk and milk products with Staphylococcus aureus (S. aureus), including methicillin-resistant strains,posing significant public health concerns. This study aimed to investigate the occurrence, antimicrobial susceptibility profiles and presence of resistance genes in S. aureus strains isolated from milk and milk products. A cross-sectional study was conducted in the Arsi highlands, Oromia, Ethiopia from March 2022 to February 2023. A total of 503 milk and milk product samples were collected, comprising 259 raw milk, 219 cottage cheese, and 25 traditional yogurt samples. S. aureus isolation and coagulase-positive staphylococci enumeration were performed using Baird-Parker agar supplemented with tellurite and egg yolk. S. aureus was further characterized based on colony morphology, Gram stain, mannitol fermentation, catalase test, and coagulase test. Phenotypic antimicrobial resistance was assessed using the Kirby-Bauer disc diffusion method, while the polymerase chain reaction (PCR) was employed for confirming the presence of S. aureus and detecting antimicrobial resistance genes. S. aureus was detected in 24.9% of the milk and milk products, with the highest occurrence in raw milk (40.9%), followed by yogurt (20%), and cottage cheese (6.4%). The geometric mean for coagulase-positive staphylococci counts in raw milk, yogurt, and cottage cheese was 4.6, 3.8, and 3.2 log10 CFU/mL, respectively. Antimicrobial resistance analysis revealed high levels of resistance to ampicillin (89.7%) and penicillin G (87.2%), with 71.8% of the isolates demonstrating multidrug resistance. Of the 16 S. aureus isolates analyzed using PCR, all were found to carry the nuc gene, with the mecA and blaZ genes detected in 50% of these isolates each. This study revealed the widespread distribution of S. aureus in milk and milk products in the Arsi highlands of Ethiopia. The isolates displayed high resistance to ampicillin and penicillin, with a concerning level of multidrug resistance. The detection of the mecA and blaZ genes in selected isolates is of particular concern, highlighting a potential public health hazard and posing a challenge to effective antimicrobial treatment. These findings highlight the urgent need to enhance hygiene standards in milk and milk product handling and promote the rational use of antimicrobial drugs. Provision of adequate training for all individuals involved in the dairy sector can help minimize contamination. These measures are crucial in addressing the threats posed by S. aureus, including methicillin-resistant strains, and ensuring the safety of milk and its products for consumers.

Assessment of the Microbiological Safety and Hygiene of Raw and Thermally Treated Milk Cheeses Marketed in Central Italy between 2013 and 2020.

A profile of the microbial safety and hygiene of cheese in central Italy was defined based on an analysis of 1373 cheeses sampled under the Italian National Control Plan for Food Safety spanning the years 2013 to 2020 and tested according to Commission Regulation (EC) No. 2073/2005 (as amended). A total of 97.4% of cheese samples were assessed as being satisfactory for food safety criteria and 80.5% for process hygiene criteria. Staphylococcal enterotoxin was found in 2/414 samples, while Salmonella spp. and Listeria monocytogenes were detected in 15 samples out of 373 and 437, respectively. Escherichia coli and coagulase-positive staphylococci counts were found unsatisfactory in 12/61 and 17/88 cheese samples, respectively. The impact of milking species, milk thermal treatment, and cheese hardness category was considered. A statistically significant association (p < 0.05) was found between milk thermal treatment and the prevalence of coagulase-positive staphylococci and Listeria monocytogenes and between hardness and unsatisfactory levels of Escherichia coli. The data depict a contained public health risk associated with these products and confirm, at the same time, the importance of strict compliance with good hygiene practices during milk and cheese production. These results can assist in bolstering risk analysis and providing insights for food safety decision making.

Ready-to-Eat Foods: A Potential Vehicle for the Spread of Coagulase-Positive Staphylococci and Antimicrobial-Resistant Staphylococcus aureus in Buea Municipality, South West Cameroon.

The consumption of ready-to-eat (RTE) foods contaminated with coagulase-positive staphylococci (CoPS) and especially Staphylococcus aureus puts consumers at a potential risk of food-borne disease or colonization and subsequent infection. This cross-sectional study determined the levels of CoPS and the presence of S. aureus in RTE foods sold in Buea municipality. A total of 420 RTE food samples, comprising 70 each of cake, bread, fruit salad, meat hot-pot, suya, and boiled rice were randomly purchased from February to August 2020. The CoPS counts were determined by culturing on Baird-Parker agar, and S. aureus was identified by amplification of the nuc gene using the polymerase chain reaction. All S. aureus isolates were screened for the presence of classical staphylococcal enterotoxin genes. To determine antimicrobial resistance profiles, each isolate was tested against 11 antimicrobials. Oxacillin-resistant S. aureus strains were analyzed for the presence of the mecA gene. Overall, 161 (38.3%) samples had detectable levels of CoPS ranging from 2.0 to 5.81 log10 CFU/g. Based on CoPS levels, 37 (8.81%) of the 420 RTE food samples-only fruit salad and meat hot-pot, had unsatisfactory microbiological quality. A total of 72 S. aureus isolates, comprising 52.78% from fruit salad, 16.67% from meat hot-pot, 12.5% from boiled rice, 9.72% from suya, 5.56% from bread, and 4.17% from cake, were recovered. None of the S. aureus isolates possessed any of the classical enterotoxin genes. All the isolates were susceptible to vancomycin and ofloxacin, while 68 (94.44%) and 66 (91.67%) were susceptible to oxacillin and ciprofloxacin, respectively. Resistance to penicillin (93.06%) was highest, followed by amoxicillin (91.67%) and erythromycin (79.17%). Four isolates were identified as methicillin-resistant S. aureus, all of which carried the mecA gene. A total of 24 antibiotypes were identified. Our findings showed that RTE foods sold in the Buea municipality are likely vehicles for the transmission of CoPS and antimicrobial-resistant S. aureus.

Toxigenic characterization, spoilage potential, and antimicrobial susceptibility of coagulase-positive Staphylococcus species isolated from Minas Frescal cheese

This study aimed to identify coagulase-positive staphylococci (CPS) species from 21 samples of clandestine Minas Frescal cheese, investigate the potential for deterioration in psychrotrophic and mesophilic conditions, verify the toxigenic potential of Staphylococcus aureus, and determine the antimicrobial susceptibility profile of toxigenic S. aureus. Species determination was performed based on the detection of β-hemolysis in 5% ovine blood agar; fermentation of mannitol, maltose, and trehalose sugars; and production of acetoin. After species determination, DNA extraction and analysis was performed for S. aureus colonies for genes encoding staphylococcal toxins (eta, etb, tst, sea, seb, sec, sed, and see) using 2 multiplex PCR assays. Isolates identified as toxigenic S. aureus were tested for antimicrobial susceptibility to tetracycline, erythromycin, clindamycin, gentamicin, ciprofloxacin, sulfazotrim, trimethoprim, streptomycin, cefoxitin, vancomycin and enrofloxacin. Elevated CPS counts were observed with an average of >6 log cfu/g. Of the 355 isolates, 177 (49.86%) were identified as S. aureus. Staphylococcus hyicus, Staphylococcus intermedius, Staphylococcus delphini, and Staphylococcus coagulans were identified in 3 (0.84%), 2 (0.56%), 2 (0.56%), and 1 (0.28%) isolates, respectively. Of the total number of S. aureus, 25 (52.08%) were positive for the gene that encodes for toxic shock toxin (TSST-1). Another 16 (33.33%) were positive for the sea gene, and 4 isolates (8.33%) were positive for see and one isolate each was positive for seb (2.08%), sec (2.08%), and etb (2.08%) genes. All isolates demonstrated lipolytic activity under mesophilic and psychrotrophic conditions. S. intermedius and S. hyicus had the most prominent proteolytic potential. Multidrug resistance was observed in most of the potentially toxigenic isolates, with clindamycin having the lowest efficiency (40%), whereas the aminoglycosides (gentamicin and streptomycin) had the highest effectiveness demonstrating inhibition in all evaluated isolates. Methicillin-resistant S. aureus (MRSA) was detected. Minas Frescal cheeses, marketed in the north of Tocantins in the Brazilian Amazon region, do not comply with legal quality standards and pose a public health risk due to the enterotoxigenic potential of multiresistant isolates, in addition to low shelf life of the samples given the high spoilage potential of this microbiota.

Factors affecting the microbiological quality and contamination of farm bulk milk by Staphylococcus aureus in dairy farms in Asella, Ethiopia

BackgroundThe determination of the microbiological quality and safety of raw milk and the associated influencing factors at the farm level is very critical given that the quality or safety of subsequent products that are further produced depends on this. Therefore, this study aimed to determine the microbiological quality and safety of bulk milk and identify associated risk factors, and assess the presence/absence of S. aureus in bulk milk with potential contaminating sources in dairy farms in Asella, Ethiopia.ResultsThe geometric means of bacterial counts in farm bulk milk were 5.25 log cfu/ml, 3.1 log cfu/ml and 2.97 log cfu/ml for total bacterial count (TBC), coliform count (CC) and coagulase-positive staphylococci count (CPS), respectively. Of the 50 dairy farms, 66, 88, and 32% had TBC, CC and CPS counts, respectively, that exceeded the standard international limits for raw cow’s milk intended for direct human consumption. TBC tended to increase as CC increased in bulk milk (r = 0.5). In the final regression model, increased TBC, CC and the contamination of farm bulk milk by S. aureus were significantly associated with dirty barns, dirty cows and soiled udder and teats. TBC was higher during the rainy season than during the dry season. The reported practice of washing teats with warm water significantly decreased CC and CPS. The occurrence of S. aureus was significantly (p < 0.05) higher in bulk farm milk (42%) than in pooled udder milk (37.3%), teat swabs (22.5%), milkers’ hand swabs (18%), bulking bucket swabs (16.7%), milking container swabs (14%), and water for cleaning of udder and milkers’ hands (10%). The questionnaire survey result showed widespred raw milk consumption habits, low level of training and poor hygienic milking practices.ConclusionsThis study revealed low-quality bulk farm milk with high bacterial counts and a high occurrence of S. aureus. This indicates the potential food safety risks due to consumption of raw milk or its products. This study suggests awareness creation to dairy farmers and the public on hygienic milk production and heat treatment of milk before consumption.

Hygienic-sanitary quality of ready-to-eat salmon sashimi (Salmo Salar)

Fifty sashimi samples from 5 restaurants were characterized for enumeration of Aerobic Psychrotrophic Heterotrophic Bacteria (APHB) and Aerobic Mesophilic Heterotrophic Bacteria (AMHB), Enterobacteriaceae, coliforms at 45ºC (thermotolerant coliforms), coagulase-positive Staphylococci, presence of Vibrio parahaemolyticus and Salmonella sp., and determination of hydrogen potential (pH) and total volatile basic nitrogen (TVB-N). The bacterial isolates were evaluated for their resistance profile to the antimicrobial agents Penicillin, Ampicillin, Cefoxitin, Cefotaxime, Amikacin, Gentamicin, Tetracycline, and Trimethropim-sulfamethoxazole. The results showed that APHB, AMHB and coagulase-positive Staphylococci counts and the determination of pH and TVB-N were in accordance with national and international standards adopted as safe limits for consumption. In contrast, the Enterobacteriaceae and thermotolerant coliforms counts and presence of Salmonella sp. and V. parahaemolyticus were in disagreement with those standards, raising concern about the hygienic-sanitary quality of sashimi. The Staphylococcus aureus and V. parahaemolyticus isolates showed resistance to Penicillin, Ampicillin, Cefoxitin, Cefotaxime, Tetracycline, Gentamicin, and Amikacin, while the Salmonella sp. isolate showed no resistance to all the antimicrobial agents studied. The results showed that 48% of the samples were fit for consumption while 52% had unsatisfactory hygienic-sanitary quality for the parameters evaluated.

Effect of Lactic Acid Bacteria Addition on the Microbiological Safety of Pasta-Filata Types of Cheeses.

In this work, the effects of different combinations of lactic acid bacteria (LAB) on the growth of coagulase-positive staphylococci (CPS) and Escherichia coli were evaluated during ripening of 23 curd cheeses, and their subsequent behavior during the manufacture and storage of pasta-filata cheeses was characterized. Three groups of cheeses were prepared in total: first, control cheeses from raw milk without LAB addition; further pasteurized milk cheeses with LAB, CPS and E. coli intentional inoculation; and finally, raw milk cheeses with LAB added. The aim was to compare the effect of LAB from starter culture, and also in combination with native LAB, and to evaluate the LAB effect as a group, and further to suggest the culture with the best inhibitory potential. Based on the results, counts of CPS increased over 24 h in control curd cheese by 1.76 ± 0.56 log CFU/g. On the other hand, in raw milk cheeses with the addition of starter culture, the increase in CPS counts by 0.76 ± 0.87 log CFU/g was noticed. Counts of E. coli increased during the first 24 h of curd manufacture by 3.56 ± 0.41 log CFU/g in cheeses without LAB addition. Contrary to this, using of LAB cultures resulted in an increase in E. coli counts by only 1.40 ± 1.07 log CFU/g. After steaming at 63.6 ± 1.9°C for 7.2 ± 2.1 min (temperature of heated acidified curd was 54.9 ± 1.7°C), CPS decreased by 0.58 ± 1.12 log CFU/g, and E. coli decreased by 1.23 ± 0.97 log CFU/g in all cheeses, regardless of LAB addition. Finally, during storage of cheeses at 6 ± 0.5°C for 28 days, the levels of E. coli in control cheeses and in raw milk LAB-enriched cheeses reached levels of 2.07 ± 2.28 log CFU/g and 1.20 ± 0.85 log CFU/g, respectively. In addition, the counts of CPS at the end of storage met the criteria of EU Commission Regulation (EC) No. 1441/2007 (2007) (less than 4 log CFU/g) in all manufactured cheeses with added LAB culture, while in the control raw milk cheeses, a level of 3.80 ± 1.22 log CFU/g was observed. Regarding the culture used, the best microbiological inhibitory effect in 28-day-old cheeses was reached by the combination of Fresco culture with Lacticaseibacillus rhamnosus GG, and the best sensory properties were judged to be those for cheeses manufactured with Culture A. A moderate negative effect of storage on overall sensory acceptance was noted, according to the final evaluation of overall acceptability of pasta-filata cheeses. The most satisfactory overall acceptability after 28 days of storage at 6°C was reached for cheese with the addition of culture A.

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

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.

Microbiological analysis of the Robiola di Roccaverano cheese by means of traditional culturing methods.

Robiola di Roccaverano is a Protected Designation of Origin soft cheese made with goat’s milk, produced in Piedmont region (Italy). The peculiarities of this cheese are: i) the use of the raw milk, ii) the addition of a Natural Milk Starter, iii) the application of traditional techniques of production and iv) the localization of the dairies in rural area. All these aspects influence the microbial flora of final product and make interesting its investigation. Samples were collected at different moment of the cheese making process and during the different seasons. In this preliminary study, the safety and the hygiene parameters of the production were evaluated. Lactic acid bacteria, moulds and yeasts involved in cheese-making process were also enumerated. Pathogens were not found in all samples and the counts of coagulase positive staphylococci were within the standard of law. The enumeration of microorganisms of technological interest demonstrated that, nevertheless the artisanal manufacturing process applied, the dairy was able to standardize the final products.

Microbial safety status of Serro artisanal cheese produced in Brazil

Considering the growing consumption of artisanal foods worldwide, we aimed to evaluate the microbial safety of Serro artisanal cheese (SAC), produced in Minas Gerais State, Brazil. This cheese is produced with raw milk using 1 of 2 natural starter cultures: "pingo" and "rala." A total of 53 SAC samples (pingo = 8; rala = 45) were obtained from different farmers and subjected to conventional and molecular assays to detect and enumerate Listeria monocytogenes, Salmonella spp., coagulase-positive staphylococci (CPS), diarrheagenic Escherichia coli, Mycobacterium tuberculosis, and Brucella abortus. The SAC samples were also subjected to an ELISA to detect classical staphylococcal enterotoxins (CSE: SEA, SEB, SEC, SED, SEE) and to PCR assays to detect staphylococcal enterotoxin-related genes (sea, seb, sec, sed, see). Coagulase-positive staphylococci isolates were obtained and tested by the same assays to detect their potential in CSE production and presence of CSE-related genes. None of the SAC samples showed any of the screened food-borne pathogens and zoonotic agents, and none showed the presence of CSE by phenotypic and genotypic approaches. Despite the absence of microbial hazards, mean counts of CPS in SAC samples were 5.2 log cfu/g (pingo starter) and 4.6 log cfu/g (rala starter), indicating poor hygiene practices during production. None of the tested CPS isolates (n = 116) produced CSE or presented CSE-related genes. Despite the relative microbial safety, hygienic conditions during SAC production must be improved to meet official guidelines established in Brazil.

Estafilococos coagulase positiva em queijos Minas Frescal produzidos em agroindústrias familiares

O objetivo deste estudo foi quantificar Estafilococos Coagulase Positiva (ECP) em queijos Minas Frescal, produzidos em seis queijarias não inspecionadas, sendo que destas, três delas utilizam leite cru e três utilizam leite pasteurizado. Foram coletadas 78 amostras, sendo 46 (24 na agroindústria e 22 no comércio) produzidas com leite pasteurizado e 32 (15 na agroindústria e 17 no comércio) fabricadas com leite cru. Queijos produzidos com leite pasteurizado apresentaram baixas contagens de ECP (1,0 x 101 a 2,0 x 103 UFC/g) e menor percentual de amostras não conformes (6,5%), as quais podem ser justificas por contaminações pós-pasteurização, decorrente de falhas higiênico-sanitárias durante a fabricação e comercialização do produto. Queijos fabricados com leite cru apresentaram maior contaminação (6,0 x 102 a 3,6 x 106 UFC/g) e maior percentual de amostras não conformes (75,0%), podendo estas serem atribuídas à contaminação da matéria-prima. Queijos informais são potencialmente capazes de causar gastroenterite e oferecem risco à saúde pública. Agroindústrias familiares devem cumprir as exigências sanitárias a fim de oferecer produtos seguros aos consumidores, evitar surtos, regularizar a produção e ampliar a comercialização, proporcionando o desenvolvimento e consolidação desta importante atividade no meio rural.

Microbiological profile of different types of salads from hospital kitchens

ABSTRACT: The objective of this work was to verify the microbiological profile of different types of salads from hospital kitchens. During the period from 2010 to 2014, the Public Food Guidance Service (SOAP) received 641 samples of salads from two public hospitals in the Central West region of the São Paulo state, where they were submitted to microbiological analysis in order to determine the most probable number (MPN) of coliforms at 35 and 45ºC, carry out Salmonella spp. study and coagulase-positive staphylococci count. The results showed that in 30.56% of samples the coliform count at 35ºC was above 1,100 MPN/g and 12.17% of samples presented coliforms at 45ºC above 100 MPN/g, which is the maximum limit established by Brazilian law. The prevalence of contaminated samples among those without heat treatment was at 97.44%, and for samples with heat treatment the prevalence was at 2.56% for both cooked and braised foods. All samples were negative for Salmonella spp. presence and showed coagulase-positive staphylococci count at &lt; 1.0 × 102 UFC/g. Although no pathogenic agents were found, the high count for indicator microorganisms in a large number of samples suggests that the practices of obtaining and manipulating these foods are inadequate, facilitating the risk of contamination with pathogens, including other agents not included in this research. Thus, food and nutrition units must pay attention to food preparation procedures, especially since these meals are served to indoor patients.

QUALIDADE MICROBIOLÓGICA DE QUEIJO MINAS FRESCAL COMERCIALIZADO NA ZONA DA MATA MINEIRA

Este trabalho objetivou avaliar a qualidade microbiológica do queijo Minasfrescal comercializado na Zona da Mata Mineira. As amostras foram coletadas em seis municípios: Juiz de Fora (33), Cataguases (7), Itamarati de Minas (4), Belmiro Braga (2), Bicas (2) e Rio Pomba (2), totalizando 50 marcas, sendo 43 de produção industrial e sete informais. As análises de pH, atividade de água (Aw), coliformes a35 ºC e a 45 ºC, Escherichia coli, estafilococos coagulase positiva, Staphylococcus aureus, Listeria monocytogenes e Salmonella sp. foram realizadas entre outubro de 2015 e janeiro de 2016. Os valores de pH variaram entre 4,98 a 7,14 e a Aw entre 0,989 a 0,904. Todas as amostras, independente da origem, apresentaram coliformesa 35 ºC, com valores variando de 1,5 x 101 a 1,1 x 106 NMP/g. Dentre as amostras, 20 (40%) apresentaram Número Mais Provável acima do limite máximo estabelecido pela legislação para coliformes a 45 ºC, sendo a média de 1,2 x 105 NMP/g. A presença de E. coli foi confirmada em 16 amostras (32%). As contagens de estafilococos coagulase positiva também foram acima do limite aceito em 16 (32%) amostras e10 (20%) continham S. aureus. Não foi constatada presença de L. monocytogenes, entretanto, Salmonella sp. foi confirmada em 20 amostras (40%). Constatou-se que, apenas 11 amostras (22%), estavam em conformidade com a legislação brasileira. Portanto, o queijo Minas frescal comercializado na região apresentou baixa qualidade microbiológica, sugerindo deficiências no processamento, transporte, armazenamento e/ou comercialização e perigo à saúde humana

SUSHI: RISCO MICROBIOLÓGICO?

A presença de estafilococos coagulase positiva e coliformes a 45ºC em alimento que será consumido cru representa potencial risco à saúde do consumidor. Buscou-se averiguar a presença de bactérias pertencentes aos grupos dos estafilococos e coliformes em sushis confeccionados à base de salmão comercializados em Parnaíba/PI. Foram realizadas análises para determinar as contagens de Bactérias Heterotróficas Cultiváveis (BHC), estafilococos coagulase positiva e NMP de coliformes a 45ºC. Os resultados foram comparados aos limites aceitáveis pela RDC nº 12 de 2001 (ANVISA). As contagens de BHC variaram de 1,3 x 10 5 a 4,0 x 10 7 UFC/g e 4,6 x 10 4 a 2,2 x 10 5 UFC/g para os estabelecimentos A e B. As contagens de estafilococos coagulase positiva para as amostras coletadas no estabelecimento A indicaram níveis acima do permitido e ausência para o estabelecimento B. A presença de coliformes a 45ºC foi confirmada para os dois estabelecimentos, no entanto, 25% das amostras do estabelecimento B expressaram níveis acima do permitido. O presente estudo demonstra o risco microbiológico em sushi preparado à base de salmão cru ao confirmar a presença de bactérias patogênicas em concentrações acima do permitido pela legislação nacional vigente.

Effects of modified atmosphere packing over the shelf life of sous vide from captive pirarucu (Arapaima gigas)

Abstract The goal of this study was to evaluate the effects of modified atmosphere in packing sous vide of pirarucu in tucupi and shrimp sauce under refrigeration. Three treatments were carried out vacuum at 98%, 60%CO2/40%N2, and 70%CO2/30%N2. The composition of CO2 and N2 was monitored along with evaluation of pH, aw, water retention capacity, acidity, texture, N-TVB and TBARS, color, mesophilic and psychotropic anaerobes, presence of Salmonella spp, sulphite-reducing Clostridia, counts of coagulase-positive Staphylococci, coliforms at 45 °C and sensorial analysis. All results were compared through ANOVA, Tukey's test, Principal Component Analysis and Multiple Factor Analysis. We observed a trend towards the reduction of CO2 in packages while O2 has increased by the end of storage. The microbiological results were within the established limits by law during the entire period. The shelf life of sous vide stored could be defined by N-TVB, TBARS, b* and C*, general acceptance, texture and flavor in 49 days of storage. Industrial relevance The development of sous vide with freshwater fish is an alternative for a value-added product to be supplied to market niches. Employing the sous vide technique on fish yields a product with better color, taste, texture, and nutrient retention than the traditional cooking processes, which makes it an attractive alternative for its consumption. This study aimed to prepare sous vide using captive pirarucu, tucupi and shrimp and to analyze the microbiological, physicochemical and sensory quality parameters during refrigerated in atmosphere modified packaging storage. The results of this study establish the product's shelf life (49 days) and contribute to defining processing and storage conditions for fish sous vide.

Prevalence, antimicrobial susceptibility and molecular typing of Methicillin-Resistant Staphylococcus aureus (MRSA) in bulk tank milk from southern Italy

This paper assesses the prevalence of MRSA in bulk tank milk (BTM) samples from southern Italy, and the relationship between the Coagulase Positive Staphylococci count (CPS) and MRSA prevalence. Of 486 BTM samples tested, 12 samples (2.5%) resulted positive for the presence of MRSA. Great genetic diversity was found among the isolates: ST1/t127 and t174/IVa, ST5/t688/V, ST8/t unknown/IVa/V, ST45/t015/IVa, ST71/t524/V, ST88/t786/Iva, ST398/t011 and t899/IVa/V and ST2781/t1730/V. All isolates were pvl-negative and icaA positive. The majority of strains (58%) carried the ses (sec, seh, seg, seo, sem and sen) genes. All tested strains resulted susceptible to amikacin, cephalotin, cloramphenicol, gentamycin, trimethoprim – sulfamethoxazole, tobramycin and vancomycin, and variably resistant to ampicillin, oxacillin and tetracycline. No statistical association between the CPS count and MRSA detection was found in the MRSA-positive samples. Although some of the spa-types and STs detected in our survey are known to cause human infections, raw milk from Italian herds in the considered area is not a common source of MRSA. Nonetheless, it is necessary to assess the risk of foodborne infection and the risk related to the handling of milk.

Qualidade microbiológica de queijo mussarela em peça e fatiado

The aim of this study was to verify the microbiological quality of mozzarella cheese sold in retail markets of Pelotas, Rio Grande do Sul, Brazil. Forty samples of mozzarella cheese were analyzed, comprising 20 samples of block cheese and 20 of sliced cheese. The cheese samples were analyzed for thermotolerant coliform counts and coagulase positive staphylococci counts, and presence of Salmonella spp and Listeria monocytogenes . The percentage of 12,5% and 5% of the sliced and block cheese samples analyzed, respectively, exceeded the microbiological standards accepted by Brazilian legislation. These results indicate the need for a better product monitoring and more concern with hygiene and sanitary practices during industrial process.

Avaliação microbiológica de carne de charque produzida industrialmente

O charque é um produto cárneo salgado e seco ao Sol obtido por desidratação da carne bovina, preservando-se, assim, por longo tempo. Apesar de passar por etapas que dificultam o crescimento de micro-organismos, pode ser contaminado durante o seu processamento. Dessa forma, objetivou-se avaliar microbiologicamente 25 amostras de charque de um frigorífico com serviço de inspeção estadual localizado no Rio Grande do Norte, Brasil. As amostras foram avaliadas quanto à contagem de estafilococos coagulase positiva, NMP de coliformes termotolerantes, Salmonella spp. e contagem de bactérias halofílicas. Avaliando a qualidade microbiológica da carne de charque, verificaram-se que cinco amostras (20%) encontravam-se em desacordo com a legislação vigente (ANVISA) para análises de estafilococos coagulase positiva, apresentando uma variação de 1,38 a 3,93 UFC/g; todas as amostras estavam em conformidade para coliformes termotolerantes. Quanto à determinação da Salmonella spp., verificou-se sua presença em sete amostras (28%), e para bactérias halofílicas, uma média de 2,25 UFC/g. Assim, as carnes de charque apresentaram micro-organismos que comprometem a qualidade do produto e podem proporcionar risco ao consumidor.

Staphylococcus aureus growth and enterotoxin production in Italian caciotta cheese

To evaluate growth and enterotoxin production of Staphylococcus aureus in raw milk caciotta, an Italian soft cheese, experimental cheesemaking trials were carried out with and without a commercial starter. Two different inocula of selected enterotoxin-producing S. aureus strains were tested: high (mean value 5.03 log CFU/mL of milk) and low (mean value 3.22 log CFU/mL of milk). Uninoculated cheeses with milk containing 2.15 log CFU/mL mean value of coagulase-positive staphylococci were also examined. With higher inocul a coagulase-positive staphylococci counts reached 7.57 log CFU/g without starter and had significantly higher values after the acidification phase than those with starter (below 6.5 log CFU/g). Using an enzyme immunoassay, enterotoxins were detected in cheeses both without and with starter, but the latter showed significantly lower photometrical absorbance values than the former. In low inoculum and uninoculated cheeses without starter, coagulase-positive staphylococci maximum values were between 5 and 6 log CFU/g, without enterotoxin production. To enhance the safety of this cheese it is fundamental to strictly prevent coagulase-positive staphylococci contamination and multiplication, particularly at the primary production level, and to correctly acidify the curd by starter cultures, which can substantially limit total coagulase-positive staphylococci increase.