Monitoring And Controlling Contamination Potential In Cold Storage Room Of Certain Fresh Fruits And Vegetables For Export

Contamination potential of possible organisms exists in cold storage rooms was monitored in both internal atmosphere of cold storage rooms and on stored fresh fruits and vegetables either in cold storage rooms subjected for export or for experiments. The highest percentage of the recovered microorganisms was recorded for fungi followed by bacteria and yeast.Certain application methods were tested on fresh fruits and vegetables in order to minimize or eradicate the contamination potential during storage period and to evaluate the quality of the products (ex vitro studies). Through laboratory tests (in vitro), the antagonistic effect of certain selected bio-control agents (yeasts or bacteria) was tested against mycelial growth of the major recovered fungi indicate a variable significant effect of each selected agent as growth reduction percentage. In ex vitro test, these agents proved variable significant effects on the percentage of rot caused by P. expansum on apricots, fruit characteristics, enzyme activities, sugars and phenol contents.The antifungal effect of Ultraviolet (UV-C Light) short wave (254 nm) was tested against growth reduction and sporulation of the major recovered fungi and indicated high growth reduction percentage. A significant effect due to exposing stripe bean, sweet potato tuber roots and lemon to UV-C light for 1,2 and 3 hrs upon natural infection (except lemon on artificial inoculation) on rot percentage (%) or fruit characteristics was determined .A significant effect on activities of oxidative enzymes; phenol and sugar contents were rather detected.Chitosan, the natural product, utilized as one of control methods caused completely suppression of fungal growth on PDA medium suspended with chitosan at certain concentrations (in vitro). Pre-inoculation and post inoculation treatments upon chitosan application were tested for their efficacy against Penicillium italicum on lemons. Pre inoculation treatment was significantly less effective in reducing rot percentage than post inoculation one. In addition, chitosan caused significant effect on maintaining fruit characteristics; inhancing activities of tested enzymes as well as phenol and sugar contents.Decontaminant treatment was applied through exposing the internal atmosphere to UV-C light to reduce contamination potential inside cold storage rooms. Microbial load of each kind of organisms (fungi, yeast, and bacteria) calculated as cfu/cm2 decreased as time of exposure increased.