Occurrence of contamination and the reduction and transfer of Alternaria toxins in apples during processing

Alternaria spp. infect and accumulate various toxic secondary metabolites in apples, posing a threat to human and animal health. This study established instrumental analytical methods for six Alternaria toxins, systematically investigated the contamination levels of Alternaria toxins in apples and their reduction and transfer patterns during processing. Apples exhibited heightened disease susceptibility at 25 °C and produced 6 Alternaria toxins in different degrees, while Alternaria toxins were not observed within 4 cm of the symptomatic site. The transfer rate to pomace after juice extraction was higher than that in juice, with transfer rates ranging from 51.9 to 62.75 % for pomace and from 21.44 to 35.79 % for juice. Canning reduced Alternaria toxins in pulp, with the highest reduction rate of 93.3 % for tenuazonic acid. A total of four Alternaria toxins were detected in the testing of market samples of apple products, and none of the assessed total daily exposure doses of toxins ingested by humans through apple products exceeded the daily intake level recommended by the EFSA. The evaluation results indicate that the risk of dietary exposure of humans is relatively low through apple products. These findings provide valuable data and theoretical support for ensuring food safety in apples.