Samira Pirola Santos Mantilla

Microbiology, sensory evaluation and shelf life of irradiated chicken breast fillets stored in air or vacuum

This work investigated the effects of different packaging methods (air and vacuum) combined with irradiation (0.0, 2.0 and 3.0 kGy) on the preservation of chicken breast fillets stored at 1oC for up to 18 days by sensorial test, determination of pH and bacterial growth. The findings indicated that the post-irradiation lag phase increased with the dose, leading to an extension in shelf-life. Vacuum-packed samples irradiated at 3.0 kGy exhibited the longest shelf life. Among the analyzed bacteria, coliforms and Listeria spp. were most sensitive to gamma radiation. All the fillets acquired more attractive coloration and better overall impression with irradiation. The combined use of vacuum packaging and irradiation (3.0 kGy) reduced the microbial populations without causing change in pH and yielded a significant shelf-life extension of refrigerated fillets, besides improving its appearance.

Refrigerated poultry breast fillets packed in modified atmosphere and irradiated: bacteriological evaluation, shelf life and sensory acceptance

In the present study the effects on shelf life and sensory acceptance of gamma-irradiated refrigerated poultry breast fillets subjected to modified atmosphere packaging (80% CO2/20% N2 or vacuum) were investigated. After irradiation with 2 kGy, sensory acceptance tests and monitoring of bacterial growth were performed in order to determine the sanitary quality of the samples. It has been found that irradiation, used in combination with modified atmosphere packaging, can double the shelf life of refrigerated poultry breast fillets by reducing the populations of aerobic mesophilic and psychrotrophic bacteria, enterobacteria, coliforms, Listeria spp. and Aeromonas spp., without significantly modifying its color or its overall appearance, the lactic acid bacteria being the most resistant to exposure to radiation and carbon dioxide.

Ocorrência de Listeria spp. em amostras de carne bovina moída comercializadas no município de Niterói, RJ, Brasil

Foram analisadas 30 amostras de carne bovina moida resfriada, previamente embaladas, provenientes de estabelecimentos comercias do municipio de Niteroi, RJ, com o objetivo de se observar a frequencia de bacterias do genero Listeria spp. Utilizou-se para isto a metodologia revisada do USDA. 50% das amostras analisadas apresentaram contaminacao por Listeria spp., sendo a L. innocua (SEELIGER & SCHOOFS, 1979) a especie isolada em maior numero, seguida pela L. monocytogenes (MURRAY et al., 1926; PIRIE, 1940). Na tipificacao sorologica, observou-se maior prevalencia de L. monocytogenes pertencente ao sorotipo 4b (50%), porem o sorotipo ½ c tambem foi identificado. As amostras que apresentaram-se contaminadas com L. monocytogenes, caracterizam-se como potencialmente capazes de ocasionar enfermidades transmitidas por alimentos.