ABSTRACT
Abstract Hibiscus sabdariffa L. is used in traditional medicine because of its bioactive properties, such as antioxidant and antibacterial. Escherichia coli is a Gram-negative bacteria and as an indicator of contamination in food. The aim of this work was to evaluate the anti-Escherichia coli effect and the change in pH on the control of aerobic mesophilic microorganisms, using hydroethanolic extract of H. sabdariffa L. in different concentrations in a meat model, verifying its potential as food additive for microbiological stability on ground beef during cooling storage. For the preparation of the treatments, the meat experimental units were elaborated with different concentrations of the vegetal extract (5, 10, 15 and 20%), ground beef and contaminated with E. coli. For pH evaluation, the meat experimental units were added different percentages of hydroethanolic extract. The H. sabdariffa L. antibacterial action reduced two logarithmic levels in practically all treatments. The best pH result was obtained in the meat containing 30% of the extract. The hydroethanolic extracts of Hibiscus sabdariffa L. showed anti-Escherichia coli activity in the presence of refrigerated ground beef. Analyzing the pH results and the count of aerobic mesophilic bacteria, it is possible this extract to be used as a natural food additive.
ABSTRACT
O objetivo deste estudo foi analisar a qualidade microbiológica de quatro marcas de ricota comercializadas na região Noroeste do Rio Grande do Sul, sendo analisados cinco lotes de cada marca. Avaliou-se a presença de coliformes totais e termotolerantes, Escherichia coli, Staphylococcus coagulase positiva, bolores, leveduras, e de Salmonella spp., além da temperatura de armazenamento e pH. Constatou-se que, 85% das amostras apresentaram contaminação por coliformes totais e 75% por coliformes legislação brasileira, RDC nº 12 de 2001. Leveduras foram encontradas em 90% das amostras e Staphylococcus coagulase positiva e Salmonella spp. não foram detectados. 80% das amostras estavam armazenadas em temperaturas superiores a 8ºC, favorecendo o desenvolvimento microbiano e 25% apresentaram valores de pH ácido. Os resultados obtidos indicaram haver falhas no processamento que, quando aliadas ao mau armazenamento, promovem o desenvolvimento de micro-organismos, os quais aceleram a deterioração do produto e representam sério risco à saúde do consumidor. Maior controle por parte das indústrias e fiscalização pelos órgãos competentes são necessários, a fim de garantir o consumo de ricotas de qualidade.
The aim of this study was to analyze the microbiological quality of four trademarks of ricotta commercialized in the northwestern of Rio Grande do Sul The samples (five lots of each brand) were evaluated for the total and thermotolerant coliforms, Escherichia coli, coagulase-positive Staphylococcus, yeasts and molds, Salmonella, storage temperature and pH. Results showed contamination by total and thermotolerant coliforms in 85% and 75% of the samples, respectively, and 50% were inappropriate for human consumption according to the Brazilian legislation (RDC nº 12, 2001). Yeasts were found in 90% of samples, but coagulase-positive Staphylococcus and Salmonella were not identified. 80% of the samples were stored at temperatures above 8°C favoring microbial growth and 25% showed acid pH values, indicating the presence of fermenting microorganisms. The results showed flaws in the ricotta in the processing environment that, allied to inadequate storage at sale points, promote the growth of microorganisms and can accelerate the deterioration of the product, besides it is a risk to consumer health. Greater control by industries and supervision by the competent agencies are required to ensure the quality of ricotta consumption.