Microbiological quality of hamburgers sold in the streets of Cuiabá - MT, Brazil and vendor hygiene-awareness

This study evaluated the microbiological quality of hamburgers and the microbe community on the hands of vendors in Cuiabá, Mato Grosso, Brazil, in relation to vendors´ awareness as to what constitute acceptable food-handling practices as part of a broad-spectrum research programme on street foods in Brazil . Sale of the hamburger known as the 'baguncinha' is common and widespread in urban Cuiabá, Mato Grosso, Brazil. Food inspectors encounter various difficulties in carrying out inspections. One hundred and five hamburgers samples were evaluated using conventional methods including tests for facultative aerobic and/or anaerobic mesophytic bacteria, coliform counts at 45 °C, the coagulase test for Staphylococcus, Gram-staining for the presence of Bacillus cereus, Clostridium sulphite reductase and Salmonella spp. The hamburgers were categorized as unsuitable for human consumption in 31.4% of samples, with those testing positive for coliforms and Staphylococcus at unacceptably high levels by Brazilian standards. High levels of microbiological contamination were detected on the hands of the food handlers and mesophytic bacterial counts reached 1.8 × 10(4) CFU/hand. Interviews were carried out by means of questionnaires to evaluate levels of awareness as to acceptable food handling practices and it was found that 80,1% of vendors had never participated in any kind of training.

Evaluation of process parameters in the industrial scale production of fish nuggets

This work reports the use of experimental design for the assessment of the effects of process parameters on the production of fish nuggets in an industrial scale environment. The effect of independent factors on the physicochemical and microbiological parameters was investigated through a full 24 experimental design. The studied factors included the temperature of fish fillet and pulp in the mixer, the temperature of the added fat, the temperature of water and the ratio of protein extraction time to emulsion time. The physicochemical analyses showed that the higher temperature of the pulp and fillet of fish, the lower the protein in the final product. Microbiological analyses revealed that the counting of Staphylococcus coagulase positive, total and thermo-tolerant coliforms were in accordance with the current legislation.

In vitro antimicrobial properties of plant essential oils thymus vulgaris, cymbopogon citratus and laurus nobilis against five important foodborne pathogens

Several essential oils of condiment and medicinal plants possess proven antimicrobial activity and are of important interest for the food industry. Therefore, the Minimum Inhibitory Concentrations (MIC) of those oils should be determined for various bacteria. MIC varies according to the oil used, the major compounds, and the physiology of the bacterium under study. In the present study, the essential oils of the plants Thymus vulgaris (time), Cymbopogon citratus (lemongrass) and Laurus nobilis (bay) were chemically quantified, and the MIC was determined on the bacteria Staphylococcus aureus ATCC 25923, Escherichia coli ATCC 25922, Listeria monocytogenes ATCC 19117, Salmonella enterica Enteritidis S64, and Pseudomonas aeruginosa ATCC 27853. The essential oil of C. citratus demonstrated bacterial activity at all concentrations tested and against all of the bacteria tested. The majority of essential oil compounds were geranial and neral. The major constituent of T. vulgaris was 1.8-cineol and of L. nobilis was linalool, which presented lower antibacterial activity, followed by 1.8-cineol. The Gram-negative bacteria demonstrated higher resistance to the use of the essential oils tested in this study. E. coli was the least sensitive and was inhibited only by the oils of C. citratus and L. nobilis.

Ocurrence of Vibrio spp., positive coagulase staphylococci and enteric bacteria in oysters (Crassostrea gigas) harvested in the south bay of Santa Catarina island, Brazil

The aim of this study was to assess the contamination of oysters (Crassostrea gigas), harvested in six different regions of the South Bay of Santa Catarina Island, with Coliforms at 45 ºC, Escherichia coli, Vibrio spp., positive coagulase staphylococci, and Salmonella sp. over a period of one year. One hundred eighty oyster samples were collected directly from their culture sites and analyzed. Each sample consisted of a pool of 12 oysters. All of the samples analyzed showed absence of Salmonella, 18 (10%) samples showed presence of Escherichia coli, 15 (8.3%) samples were positive for V. alginolyticus, and Vibriocholerae was detected in 4 samples (2.2%). The counts of positive-coagulase staphylococci varied from <10 to 1.9 x 102 CFU.g-1, whereas the counts of Coliforms at 45 ºC and E. coli ranged from <3 to 1.5 x 102 MPN.g-1 and <3 and 4.3 x 10 MPN.g-1, respectively. Counts of V. parahaemolyticus and V. vulnificus ranged between <3 and 7 MPN.g-1, for both microorganisms. This suggests the need for monitoring these Vibrios contamination in oysters. Based on the results of the microbiological assays, the samples analyzed showed acceptable bacteriological quality, i.e., they were within the parameters established by Brazilian Legislation.

Enterotoxigenic potential of Staphylococcus aureus isolated from Artisan Minas cheese from the Serra da Canastra - MG, Brazil

This study aimed to evaluate the presence of enterotoxigenic S. aureus in the endogenous starter and in Artisan Minas cheeses from the Serra da Canastra. Sixteen samples of endogenous starters and cheese were collected during the rainy and dry seasons. The isolation and enumeration of S. aureus were performed using the PetrifilmTM-Rapid S. aureus Plate Count method. The presence of enterotoxin in the cheese samples was analyzed by the Optimal Sensitivity Plate (OSP) method and the ELFA-VIDAS®-Staph enterotoxin-II assay. S. aureus strains were tested for their ability to produce enterotoxins using the Optimal Sensitivity Plate (OSP) method and the polymerase chain reaction (PCR) assay for the classical enterotoxin genes. The Optimal Sensitivity Plate (OSP) method data showed that staphylococcal enterotoxin A (SEA) was detected in 75% of the cheese samples, but no toxin was detected with the ELFA-VIDAS method. It was found that 12.5% of the isolated strains produced staphylococcal enterotoxin A (SEA) and staphylococcal enterotoxin C (SEC). When using the the polymerase chain reaction (PCR) assay, only one isolate was found to harbor an enterotoxin gene, contrary our expectations. However, discrepancies between the immunological and molecular assays are not uncommon. Despite the fact that most isolates did not produce classical enterotoxins, high S. aureus counts in the cheese samples causes concern since there is a risk of the presence of non-classical enterotoxins.

Detection of exopolysaccharide production and biofilm-related genes in Staphylococcus spp. isolated from a poultry processing plant

Staphylococcus spp. can survive in biofilms for long periods of time, and they can be transferred from one point to another and cause environmental contamination in food processing. The aim of this study was to detect Staphylococcus strains isolated from a poultry processing plant by the presence of adhesion genes and the phenotypic production of exopolysaccharide. In the present study, the production of exopolysaccharide and the presence of adhesion genes in 65 strains of Staphylococcus spp. were evaluated. All strains of Staphylococcus spp. produced exopolysaccharide, as confirmed by formation of black and opaque colonies in Congo Red Agar. The variation of sucrose content was critical for the production of exopolysaccharide in Congo Red Agar since at low sucrose concentrations all strains presented a characteristic result, i.e., there was no exopolysaccharide production. The atl gene was found in all strains, and the icaA and icaD genes were found in 97% of them. The data obtained suggest that Staphylococcus spp. isolated from the poultry processing plant evaluated has a potential for biofilm formation. An efficient control of this microorganism in food processing environment is necessary as they may represent a potential risk to consumers.

Inactivation of Staphylococcus aureus in raw salmon with supercritical CO2 using experimental design

Abstract Considering the microbial safety of consumption of raw foods (Asian food), this study aimed to explore the inactivation S. aureus in raw salmon by supercritical CO2 treatment (SC-CO2). For this purpose, experimental design methodology was employed as a tool to evaluate the effects of pressure (120-220 bar), the depressurization rate (10 to 100 bar.min–1) and the salmon:CO2 mass relation (1:0.2 to 1:1.0). It was observed that the pressure and the depressurization rate was statistically significant, i.e. the higher the system pressure and depressurization rate, the greater the microbial inactivation. The salmon: CO2 mass relation did not influence the S. aureus inactivation in raw salmon. There was a total reduction in S. aureus with 225 bar, a depressurizing rate of 100 bar.min–1, a salmon: CO2 mass relation of 1:0.6, for 2 hours at 33 °C.

Peritonites em pacientes em diálise peritoneal: análise de um único centro brasileiro segundo a Sociedade Internacional de Diálise Peritoneal

INTRODUÇÃO: A peritonite continua sendo a maior complicação para os pacientes em diálise peritoneal (DP). OBJETIVO: Este estudo teve como objetivo determinar as taxas de peritonite por episódio/ano (ep./ ano), ep./ano por microrganismo causador e pela mediana do número de peritonites nos pacientes em diálise peritoneal do Serviço de Nefrologia do Hospital São Lucas da PUCRS. MÉTODOS: Estudo retrospectivo e descritivo, no qual a amostra foi composta de pacientes que fizeram diálise peritoneal no Serviço de Nefrologia do HSL no período de 1984 a agosto de 2012; foram considerados somente os que possuíam dados completos. RESULTADOS: Dos 427 pacientes analisados, 53,2% eram do sexo feminino, com idade média de 48,0 ± 19,9 anos, 13% (56) de diabéticos e 71,5% (303) dos pacientes realizavam seu próprio tratamento. Ocorreram 503 episódios de peritonite e 255 pacientes tiveram pelo menos uma peritonite. Staphylococcus coagulase negativo foi o microrganismo mais prevalente. As causas de saída de tratamento foram óbito, transplante renal e peritonite, com 34,4, 25,8 e 19,2%, respectivamente. A taxa de peritonite foi de 0,63 ep./ano e ep./ ano por microrganismo foi de 0,18 ep./ ano para Staphylococcus coagulase negativo, e de 0,12 ep./ano para Staphilococcus aureus e Gram negativos. A mediana da unidade foi de 0,41. CONCLUSÃO: A taxa de peritonite ep./ano, e a mediana dos pacientes estudados encontram-se dentro do mínimo preconizado, mas abaixo das metas sugeridas, assim como a caracterização de ep./ano por microrganismo.