PROCESS-MODIFIED ATMOSPHERE AND HUMIDITY PARAMETERS FOR HIGH-QUALITY SLICED MUSHROOMS (AGARICUS BISPORUS L.)

Mushrooms received one of the following four treatments: washed with water, sliced with a blunt blade and stored in air (AIR) at 4 and 8C, or were treated with H2O2/isoascorbate, then gently sliced with a razor blade, followed by storage in controlled humidity and modified atmosphere (HMA) chambers (96% relative humidity, and 3% O-2, 3% CO2 bal N-2) at 4 or 8C. Sensory analysis showed that more severe processing with water washing and air storage resulted in an overall poor sensory quality with a greater loss of appearance, increased mushroom maturity, surface browning with tissue softening and a loss of aroma acceptability. Microbial loads were greater, particularly at 8C. By contrast, mild slicing and an antibacterial/anti-browning treatment combined with high HMA storage had beneficial effects on quality. These conditions resulted in better sensory scores, less cap development and lower microbial loads. Increasing storage temperature from 4 to 8C resulted in a shorter shelf life under both storage atmospheres. PRACTICAL APPLICATIONS This study highlights the effects of different preparation and storage practices on the quality of sliced mushrooms to determine processing and storage conditions that improved quality. The results support the use of low impact slicing combined with an H2O2/isoascorbate treatment, followed by humidity and modified atmosphere storage at 4C as an effective strategy for extending the shelf life of sliced mushrooms. These data from chamber experiments illustrate the challenges faced in supplying packaging materials, which provide ideal storage environments. This work can be relevant for producers and processors who want a mushrom product with maximum quality, safe and has an extended shelf life.