Improving quality of spices during storage using physical treatments.

摘要

Samples of spices (black pepper and cumin) collected from local markets were examined for total fungal contamination (T.F). Different fungal genera and species were isolated and identified. The selected spices were treated separately with physical treatments ( gamma rays, thermal and washing). The efficiency of these treatments on TF and aflatoxins (AFs) content were investigated. The obtained results revealed that raw marketed spices were contaminated naturally by different species of fungi i.e. Aspergillus parasiticus, Aspergillus flavus, Aspergillus niger, Aspergillus ochraseus, Aspergillus terreus, Penicillium sp., Mucor sp., Rhizopus sp., Fusarium sp. and Cladosporium sp. at different levels, gamma -irradiation at dose level 10 kGy completely sterilized the spices samples during the storage period (10 weeks), whereas some fungal growth started again after few weeks of storage on samples exposed to 4.0 and 5.0 kGy. In the same time, thermal and washing treatments failed to control TF during storage. The detection of AFs proved presence of B₁, G₂, G₁ in black pepper, B₁, B₂ in cumin with different concentrations. Generally, high gamma -irradiation doses (10, 20 kGy) slightly reduced the AFs in spices samples. Thermal treatments and washing also slightly decreased the AFs contaminated in the tested spices. Slight reduction was clear in some AFs which can be express as linear regression analysis with high significant values (R2) were tabulated in details. Finally, the obtained results proved the preferability of using high dose level of 10 kGy for decontamination of TF exist in spices on the condition they are AFs free for the safe human consumption.