RESUMEN
The objective of this work was to assess the efficacy of sodium hypochlorite and peracetic acid for sanitization of Brazil nuts. To evaluate the natural microbiota of the nuts, the total bacteria and fungi as well as the Aspergillus section Flavi were counted. The moisture, water activity and the presence of aflatoxins was quantified. The response surface method was used to determine the influence of exposure time and sanitizers concentration on the reduction of Aspergillus nomius inoculated on the nuts. Microbiological, sensory and quantification analyzes of aflatoxins were performed under optimum conditions The evaluation of the initial contamination of the nuts, despite presenting high microbiological contamination, humidity and water activity, was not detected aflatoxins in any samples. In artificially inoculated samples, the response surface and the desirability function were obtained to determine the optimal point of use for each sanitizer. The nuts had high microbiological contamination, moisture content and water activity. Aflatoxins were not detected in any samples. The response surface and desirability function indicated the optimal sanitization conditions were 250 mg/L and 8.5 min and 140 mg/L and 15 min for sodium hypochlorite and peracetic acid, respectively. Reductions greater than 2 log CFU/g were obtained with sodium hypochlorite and of 1 log CFU/g for peracetic acid. In the tests performed with new Brazil nuts samples under the optimized conditions, reductions of less than 2 log CFU/g were obtained. Aflatoxin B1 was detected in one untreated sample (1.51 µg/kg), one sample treated with sodium hypochlorite (0.60 µg/kg) and two samples treated with peracetic acid (0.64 and 0.72 µg/kg). Demonstrating that the sanitizers in the concentrations used had no action on aflatoxins, despite being efficient for fungal control. The treatments did not cause an unacceptable sensorial impact on the samples.
Asunto(s)
Aspergillus/efectos de los fármacos , Bertholletia/microbiología , Desinfectantes/farmacología , Contaminación de Alimentos/prevención & control , Ácido Peracético/farmacología , Hipoclorito de Sodio/farmacología , Aflatoxinas/análisis , Microbiología de AlimentosRESUMEN
The goal of this study was to evaluate sous vide fish and assess the influence of time and temperature on the pasteurization process through quality parameters. The raw material (tambaqui fillets) and the sous vide underwent physical, physicochemical, and microbiological analyses. A sauce was prepared containing soy sauce, water, horseradish and garlic flakes. The product's pasteurization parameters of time and temperature were defined according to a 22 central composite rotatable design (CCRD), and the dependent variables were water holding capacity (WHC) and instrumental texture aiming at obtaining high WHC values for the product to maintain the desired juiciness. The microbiological analysis required by legislation have indicated that the fish fillets and sous vide were within de standard. The values of total coliforms found in the samples (fillets and sous vide) analyzed were below the critical level of 10² CFU/g. The counts of sulphite-reducing clostridia and psychrotrophic and mesophilic bacteria on plates in the samples were <1x10 CFU/g. In conclusion, temperature was the most important factor in the pasteurization process, significantly contributing to the quality of the final product. The mathematical models proposed were considered predictive for each response.
O objetivo deste estudo foi avaliar a influência do tempo e da temperatura no processo de pasteurização do sous vide de peixe por meio dos parâmetros de qualidade. Foram realizadas análises físicas, físico-químicas e microbiológicas na matéria-prima (filé de tambaqui) e no sous vide. Foi preparado um molho contendo molho de soja, água, raiz forte e flocos de alho. Parâmetros de pasteurização do produto (tempo x temperatura) foram definidos de acordo com um projeto de 2x2 rotativo composto central (DRCC), e as variáveis dependentes foram capacidade de retenção de água (CRA) e textura instrumental, visando à obtenção de altos valores de CRA para que o produto obtivesse a suculência desejada. As análises microbiológicas exigidas na legislação indicaram que a matéria-prima e o sous vide encontravam-se dentro dos padrões estabelecidos. Os valores de coliformes totais encontrados nas amostras (filés e sous vide) analisadas foram inferiores ao nível crítico de 10² UFC/g. As contagens de clostrídios sulfitorredutores e bactérias psicrotróficas e mesófilas em placas nas amostras foram <1x10 UFC/g. Concluiu-se que a temperatura foi o fator mais importante no processo de pasteurização, contribuindo de forma significativa para a qualidade do produto final. Os modelos matemáticos propostos foram preditivos para cada resposta.