Determination of coconut cadang-cadang viroid (CCCVd) contamination in unprocessed coconut export products
2002
Rodriguez, M.J.B. | Estioko, L.P. (Philippine Coconut Authority, Albay (Philippines))
The prevalence of the cadang-cadang disease in some parts of the country has caused some problems in the international trade of coconut products. Earlier studies revealed the presence of the pathogen (CCCVd) in different parts of an infected palm at varied concentration levels. The possible CCCVd contamination of some coconut export products was verified. The effects of various physical and chemical elements on the CCCVd isolate were likewise determined, with focus on those that were applied in food and non-food product processing. Findings showed that using an improved molecular hybridization assay (MHA) previously developed for field indexing, no CCCVd was detected in the meat and water (solid and liquid endosperm) of young and mature coconuts from diseased palms but the viroid was present in the husk (pericarp). The chance for the disease to be exported in fresh young coconuts or `buko' is negligible since infected nuts are relatively small in size and scarified on the outer surface. By-products from mature coconut husks like coco peat and coir fiber could be considered free of CCCVd as the husks are composed of practically dead tissues and the viroid could not survive additional exposure to processing conditions. CCCVd was found insensitive to microwave/ultraviolet/ionizing radiation, low temperature pasteurization, freezing/thawing, and phenol/sodium metabisulfite treatment. CCCVd was inacted/degraded by incubation at 100 deg C for 45 minutes, by autoclaving at 118 deg C for 15-30 minutes, and by treatment with enzyme RNAse, alkali solution (e.g., 10% KOH) and at least 11% formalin
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