Behaviour of Listeria monocytogenes in packaged fresh mushrooms (Agaricus bisporus)

Aims: The aim of this study was to evaluate the potential of Listeria monoc ytogenes to grow in mushrooms packaged in two different types of PVC films when stored at 4 degreesC and 10 degreesC. Methods and Results: Mushrooms were packed in two polymeric films (perforat ed and nonperforated PVC) and stored at 4 degreesC and 10 degreesC. The car bon dioxide and oxygen content inside the packages, aerobic mesophiles, psy chrotrophs, Pseudomonas spp., Listeria monocytogenes, faecal coliforms, Esc herichia coli, anaerobic spores and major sensory factors were determined. The mushrooms packaged in nonperforated film and stored at 4 degreesC had t he most desirable quality parameters (texture, development stage and absenc e of moulds). Listeria monocytogenes was able to grow at 4 degreesC and 10 degreesC in inoculated mushrooms packaged in perforated and nonperforated f ilms between 1 and 2 log units during the first 48 h. After 10 d of storage , the populations of L. monocytogenes were higher in mushrooms packaged in nonperforated film and stored at 10 degreesC. Conclusions: MAP followed by storage at 4 degreesC or 10 degreesC extends t he shelf life by maintaining an acceptable appearance, but allows the growt h and survival of L. monocytogenes. Significance and Impact of the Study: According to this study additional hu rdles must be studied in order to prevent the growth of L. monocytogenes.