Contaminacion por patulina durante la frigoconservacion y en la etapa previa a la elaboracion de productos de manzana

Resumen

Accumulation of patulin in apples and pears and subsequently in their by-products is caused mostly by Penicillium expansum which causes blue mould. Patulin can damage organs and tissues in animals and some studies revealed carcinogenic and teratogenic effects. Process-grade apples are mostly cold stored apples (which may have developed blue rot during storage) and low quality apples (ground harvested or visibly wounded apples) and thus, patulin contamination of raw material occurs. The influence of cold storage and further ambient storage prior to processing on patulin accumulation in apples were studied in this thesis. A morfo-ecophysiological study revealed that almost 100% of P. expansum isolates assayed in this study presented strong aggressiveness to apples and were patulin producers. Different degrees of sensitivity to fungicides was observed and some isolates were resistant to fungicides Duration of cold storage influenced on patulin accumulation. However, when lesions development was minimized, patulin amounts detected in apples were smaller regardless of duration of cold storage. Inoculum size an intraspecific interactions affected rot development and patulin accumulation. Modified atmospheres controlled patulin accumulation in longer storages. Ripeness degree of apples when harvesting influences on fungicide efficiency, which could not avoid completely fruit spoilage. The treatment with biocontrol agents seemed to be an alternative to fungicides not only avoiding mould growth but also controlling patulin accumulation. Further storage at ambient temperature led to rapid rot development and strong patulin accumulation in all cases. The size of the lesion caused by P. expansum at the end of cold storage significantly influenced on patulin accumulated during ambient storage and postharvest treatments assayed in this study lost their efficiency at this stage too. Thus, efficiency of such postharvest treatments during ambient storage depended on their effec