The sensory and microbiological quality of fresh sliced mushroom ( Agaricus bisporus L.) packaged in modified atmospheres.

The effect of modified atmospheres, generated by using different packaging films, on the quality of sliced mushrooms was evaluated. The carbon dioxide and oxygen content inside the packages as well as the colour, texture, weight loss, sensory attributes, mesophiles, psychrotrophs, Pseudomonas fluorescens, faecal coliforms, Escherichia coli and anaerobic spores were determined. Modified atmospheres containing 2.5% CO2 and 10–20% O2 reduced the microbial counts and improved the mushrooms’ appearance when compared with an air atmosphere. Modified atmospheres containing 15% CO2 and <0.1% O2 inhibited mushroom development and toughening and reduced microbial growth. Although these atmospheres had no effect on colour, they did allow the development of off odours and anaerobic spores were detected. No differences in microbial growth or mushroom spoilage were observed under the different moisture contents generated in the packages at 4 °C. Aerobic bacteria counts were considered very high even at the beginning. [ABSTRACT FROM AUTHOR]