Study of microbial contamination of dried condiment plants

Written by György Éva, Laslo Éva, András Csaba Dezső, György Elza-Márta

Spices are plant parts containing flavouring and odouring materials, which, in several cases, possess antimicrobial activity. In contrast with the antimicrobial efficiency of their chemical constituents, the microbial contamination of dried spices can represent a real hazard of food spoilage, and even food contamination. The microbial contamination is a consequence of the growing and improper processing conditions of spices. Out of the allochton microorganisms, which cause illnesses (infections and toxicoses) transmitted by spices through food-products, the sporogenic aerobic bacteria (Bacillus) and the anaerobic (Clostridium) bacteria have the main role, as well as the micotoxicogenic micromicetes (Aspergillus sp.). In our study, the microbial contamination level of four commercially available, autohtonic dried spices were examined (thyme, caraway, savory and dill). The result shows, that the residual (bacterial and fungal) contamination of the products was significant. Aerobic and anaerobic sporogenic bacteria, anaerobic sulphite-reducing bacteria (Clostridium perfringens), and also micromicetes from Alternaria, Penicillium and Aspergillus genus (even some micotoxicogenic species) were detected. At the same time, we examined the microbial destruction rates during various decontamination procedures (washing with water and hydrogen peroxide solution, mild heating, ultaviolet and microwave irradiation) applied on spice samples.


Keywords: dried spices, microbial contamination, sporogenic bacteria, Clostridium, micotoxicogenic micromicetes, decontamination.

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