Avaliação microbiológica e sensorial da vida-útil de cortes de peito de frango irradiados

Photohydroionisation for disinfection of poultry litter

1. This study evaluated photohydroionisation efficiency on the disinfection of new shavings used as substrate for litter in the poultry industry, pre-inoculated with bacterial, fungal and viral agents.2. Each replicate consisted of 250 g of new shavings sterilised by autoclaving, challenged with bacterial (Escherichia coli, Staphylococcus aureus, and Salmonella enterica, serovar Abony), fungal (Saccharomyces cerevisiae) and viral inoculum (Gumboro disease virus). The experiment consisted of six replicates at four times (0, 1, 5 or 10 min exposure) of photohydroionisation. The disinfection process was performed in a bench photohydroionisation device with four ultraviolet lamps. The agents inoculated in the shavings were analysed after the disinfection process.3. The counts of enterobacteria and total bacteria showed a quadratic effect. In contrast, the counts of fungi and viruses showed a negative linear effect with an increase in the time of photohydroionisation. The enterobacteria showed a linear response plateau effect (LRP), with a minimum time point of 5.498 minutes at a minimum contamination of 0.666 CFU/g and a reduction of 82.27% of the pre-established inoculum. Total bacteria had an LRP effect with a minimum time point of 1.902 minutes at minimum contamination of 1.739 CFU/g and a reduction of 50.0% of the pre-established inoculum. An LRP effect was found for fungi, with a minimum time point of 7.931 minutes in minimum contamination of 3.380 CFU/g, and with a reduction of 11.0% of the pre-established inoculum. For viruses, there was an LRP effect with a minimum time point of 5.012 minutes in minimum contamination of 0.000 viral titre per 100 g of shavings, which was reduced by 100% of the pre-established inoculum.4. Photohydroionisation in the disinfection of new shavings used as poultry litter has partial potential as a microbiological control tool, as a complete reduction occurred only for the viruses, whereas for bacteria and fungi only partial reductions of these microorganisms were observed.

Predicting bacterial growth in raw, salted, and cooked chicken breast fillets during storage

Growth curves were evaluated for aerobic mesophilic and psychrotrophic bacteria, Pseudomonas spp. and Staphylococcus spp., grown in raw, salted, and cooked chicken breast at 2, 4, 7, 10, 15, and 20 ℃, respectively, using the modified Gompertz and modified logistic models. Shelf life was determined based on microbiological counts and sensory analysis. Temperature increase reduced the shelf life, which varied from 10 to 26 days at 2 ℃, from nine to 21 days at 4 ℃, from six to 12 days at 7 ℃, from four to eight days at 10 ℃, from two to four days at 15 ℃, and from one to two days at 20 ℃. In most cases, cooked chicken breast showed the highest microbial count, followed by raw breast and lastly salted breast. The data obtained here were useful for the generation of mathematical models and parameters. The models presented high correlation and can be used for predictive purposes in the poultry meat supply chain.

Irradiated vacuum-packed lamb meat stored under refrigeration: microbiology, physicochemical stability and sensory acceptance

Reducing spoilage and indicator bacteria is important for microbiological stability in meat and meat products. The objective was to evaluate the effect of different doses of gamma radiation on the shelf-life of lamb meat, vacuum-packed and stored under refrigeration, by assessing the microbiological safety, physicochemical stability and sensory quality. Lamb loin cuts (Longissimus dorsi) were irradiated with 1.5kGy and 3.0kGy. The samples, including control, were stored at 1±1°C during 56days. Samples were analyzed on zero, 14, 28, 42 and 56days by their microbiological and physicochemical characteristics. Sensory quality was carried out on day zero. The results showed a reduction (p<0.05) in the microbial load of the irradiated samples. The acceptance of lamb loins was not affected (p>0.05) by the radiation doses. Thus gamma irradiation at 3.0kGy was effective in reducing the content of microorganisms, without harming the physicochemical characteristics evaluated.

Avaliação microbiológica e físico-química de linguiça toscana no Município de Mossoró, RN

Com o objetivo de avaliar a qualidade microbiológica e físico-química da linguiça toscana comercializada no Município de Mossoró, RN, foram analisadas 28 amostras de seis supermercados, verificando-se o Número Mais Provável (NMP) de coliformes termotolerantes, Salmonella spp. e bactérias psicrotróficas, umidade, pH e atividade de água. Todas as amostras estavam dentro do padrão vigente que estabelece um limite máximo de 5 x 10³ NMP/g-1 para coliformes termotole-rantes conforme a ANVISA. Na contagem de bactérias psicrotróficas houve uma variação de 2,9 x 10¹ a 1,31 x 10(4) UFC/g-1. Das 28 amostras pesquisadas quanto a presença de Salmonella spp., em cinco verificou-se a presença deste micro-organismo em 25 g. Para umidade, todas as amostras encontravam-se dentro da legislação estabelecida (< 70%) e para atividade de água os limites variaram de 0,772 a 0,809. Os valores de pH das amostras estavam entre 5,7 e 6,2. Apesar das amostras analisadas estarem dentro do estabelecido pela legislação brasileira, faz necessária a aplicação de boas práticas, visto que a contaminação por micro-organismos psicrotróficos e Salmonella foi significativa, podendo diminuir a vida de prateleira do produto e causar danos a saúde pública.

Effect of the gamma radiation dose rate on psychrotrophic bacteria, thiobarbituric acid reactive substances, and sensory characteristics of mechanically deboned chicken meat

Frozen samples of mechanically deboned chicken meat (MDCM) with skin were irradiated with gamma radiation doses of 0.0 kGy (control) and 3 kGy at 2 different radiation dose rates: 0.32 kGy/h (3 kGy) and 4.04 kGy/h (3 kGy). Batches of irradiated and control samples were evaluated during 11 d of refrigerated (2 ± 1 °C) storage for the following parameters: total psychrotrophic bacteria count, thiobarbituric acid reactive substances (TBARS), evaluation of objective color (L*, a*, and b*) and a sensory evaluation (irradiated odor, oxidized odor, pink and brown colors). No statistical difference (P > 0.05) was found amongst the TBARS values obtained for the MDCM samples irradiated with dose rates of 0.32 and 4.04 kGy/h. There was a significant increase (P < 0.05) in the psychrotrophic bacterial count as from the 7th day of refrigerated storage, for the MDCM samples irradiated at the dose rate of 4.04 kGy/h. With respect to the attribute of oxidized odor, the samples irradiated with a dose rate of 0.32 kGy/h showed a stronger intensity and were significantly different (P < 0.05) from the sample irradiated with a dose rate of 4.04 kGy/h on days 0 and 2 of refrigerated storage. Irradiation with a dose rate of 4.04 kGy/h (3 kGy) was shown to be the best condition for the processing of MDCM according to the evaluation of all the variables, under the conditions of this study. Practical Application:  The results obtained for the application of different dose rates of ionizing radiation to mechanically deboned chicken meat will provide the food industry with information concerning the definition of the best processing conditions to maximize the sensory and food quality.