Microbiological risk estimation at walnuts long-term storage

Abstract

The paper presents a bibliographic and experimental study of the microbiological incidence of Juglans regia L. walnuts at long-term storage. It was effectuated the microbiological control of autochthonous walnuts stored at different ambient conditions. We found that an improper storage leads to an increased risk of nuts infection with various microorganisms such as fungi, bacteria and acaridae. It is important to mention that the walnuts are vulnerable to fungi attack with Aspergillus flavus and A. parasiticus, species that produce aflatoxins, considered to be carcinogenic. Other isolated fungi in walnuts are: Alternarea, Penicillium, Phoma, Botryosphaeria, Fusarium, Cladosporium, etc. Microorganisms which are presented in walnuts may produce lipolytic enzymes that degrade the product quality and safety; also the same impact can be reflected on other foods based on these fruits. There are many factors that have a great influence on walnuts quality and safety. The most important are climatic conditions, varieties, cultivation methods and storage methods.