A Study Concerned with the Factors Affecting the Fungal Growth and Aflatoxin Production During Storage of Pistachio in Kerman Province

Subject Areas : Microbiology

محمد  Moradi ¹ (استادیار پژوهش، بخش گیاه پزشکی، مؤسسه تحقیقات پسته کشور، ایران)
حسین  Hokm Abadi ² (استادیار پژوهش، بخش باغبانی، مؤسسه تحقیقات پسته کشور، ایران)
S. R  Fani ³ (کارشناس، بخش گیاه‌پزشکی، مرکز تحقیقات کشاورزی و منابع طبیعی یزد، ایران)

Received: 2014-03-18 Accepted : 2014-07-15 Published : 2015-03-21

Keywords: Aspergillus, Relative humidity, storage, temperature, Water activity,

Abstract :

Introduction: Aflatoxin contamination might occur due to the improper storage conditions ofharvested pistachios. Different environmental factors affect the fungal growth and mycotoxinproduction as the harmful secondary metabolites. Improved storage conditions can beeffective to prevent the contamination of pistachios.Materials and Methods: Environmental factors consisting of kernel moisture content,relative humidity, temperature, water activity and fungi and pests might affect thecontamination of pistachio. These were studied in 47 stores and warehouses in the cities ofKerman, Sirjan, Zarand and Rafsanjan regions at three month intervals for the storage periodof 12 months.Results: The levels of water activity and kernel moisture content in this study ranged from0.12 to 0.46 and 3.1 to 5.3 (%), respectively. In most stores, the average of relative humidityranged from 24 to 26 % with minimum and maximum values of 13.7 and 36.5 respectivelyand average temperature of 23.3 to 26.1 ZC. On the other hand, observed low levels of kernelmoisture content and water activity remained at a constant level for most sampling times.These results indicated that equilibrium moisture content was not in favor of Aspergillusflavus growth and aflatoxin production. The observation also showed that the frequency ofstorage pest contamination was less than 1% and Aspergillus contamination varied fromundetectable to 1 %.Conclusion: The stores or warehouses conditions concerned with pistachio in Kermanprovince are not in situations to create and promote fungal growth and aflatoxin production.