José María García

Effect of High Temperature Treatments on Growth of "Penicillium" spp. and their Development on "Valencia" Oranges

The effect of time (up to 24h) and temperature (40 to 55°C) has been evaluated on in vitro growth of Penicillium digitatum and Penicillium italicum on potato dextrose agar plates or on ‘Valencia’ oranges (Citrus sinensis), previously inoculated with those pathogens. The effect of treatment on the fruit quality parameters has also been evaluated. In vitro, at 40 and 45°C, an exposure of 24h was required to inhibit subsequent mycelial growth of both pathogens during incubation for 1 week at 25°C. However, at 50 and 55°C, only 18 or 9h (6h for P. digitatum), respectively, were needed to achieve the same effect on both pathogens. Inoculated fruit was exposed for 18h at 40°C then stored for 5 days at 5°C plus 7 days at 20°C, and the experiment was repeated at three locations and over two fruit seasons. This curing regime controlled both pathogens effectively. Concerning quality changes, after cold storage (5°C), treated fruits showed a significant reduction in acid content and a slight delay on skin yellowing, on softening, and on weight losses, compared to the control fruits. These results suggest that the curing treatment could be a non-chemical alternative to the postharvest fungicides now used to control citrus green and blue moulds.

Effects of Postharvest Curing Treatment on Quality of Citrus Fruit

Effects of Postharvest Curing Treatment on Quality of Citrus Fruit In this study we evaluated the effect of temperature and time on oranges decay development of Penicillium digitatum and Penicillium italicum, the most postharvest diseases of citrus fruit. The assays carried out in inoculated ‘Valencia late’ oranges showed in both seasons an excellent control of both pathogens, when fruits were exposed to treatments at 40°C for 18 h, and stores for 5 days at 5°C plus 7 days at 20°C. Concerning quality changes slightly effects were observed on fruits submitted to curing treatment. These results suggest that this treatment could be an environmental friendly alternative to chemical fungicides in oranges packinghouses. Wpływ Pozbiorczego Traktowania Na Jakość Owoców Cytrusowych W badaniach oceniono wpływ pozbiorczego traktowania owoców pamarańczy wysoką temperaturą na uszkodzenia spowodowane przez Penicillim digitatum i Penicillium italicum (najbardziej popularne uszkodzenia owoców cytrusowych). Próby wykonane na inokulowanych pomarańczach ‘Velencia late’ wykazały, że w dwóch kolejnych sezonach wystąpiły wyraźnie mniejsze uszkodzenia spowodowane przez obydwa patogeny, jeżeli owoce zostały potraktowane temperaturą 40°C przez 18 godzin i następnie przechowywane przez 5 dni w temperaturze 5°C i kolejne 7 dni w temperaturze 20°C. Zaobserwowano również nieznaczny wpływ pozbiorczego traktowania owoców na zmiany jakościowe podczas przechowywania. Uzyskane wyniki wskazują, że pozbiorcze traktowanie owoców pomarańczy wysoką temperaturą może być bezpieczną dla środowiska alternatywą dla chemicznej ochrony (fungicydy) stosowanej w pakowniach owoców.