Aflatoxin Contamination and Aflatoxin-producing Strain Screening in Dried Red Chili Peppers From Different Origins.

Abstract

The contamination of spices with aflatoxin (AF) raises concerns regarding its health risks. In this study, 51 samples of dried red chili peppers (including 10 varieties collected from three regions) were used to investigate the AF contamination of dried red chili peppers sold in China, and the toxigenic characteristics of Aspergillus flavus strains isolated from chili peppers. AFs were identified using immunoaffinity column purification, derivatization, and high-performance liquid chromatography with fluorescence detection. The AF content in various types of dried red chili peppers sold in the Chinese market was generally low (≤7.19 µg/kg), below the limit of the relevant standard (10 µg/kg). The frequency of suspected A. flavus strains isolated from chili peppers was high (24/51), with a high toxigenic strain ratio of 29.17%. Further investigation revealed that 25-30 °C was the optimal temperature for toxin production by these toxigenic strains. This indicated that dried chilled peppers have a significant risk of AF contamination. Therefore, the findings of this study suggest that long-term storage of dried chili peppers should be conducted at temperatures below 25 °C or above 37 °C to mitigate the problem of AF contamination exceeding the levels allowed by the standards, providing new insights for the prevention and control of AF contamination of dried red chili peppers.