Detection, Distribution And Control On Mycotoxin In Apple Fruits

The core rot and blue mold of apple fruit were the most postharvest diseases causing by Trichothecium roseum and Penicillium expansum in Northwest of China. Besides causing serious economic loss, the disease is also associated with high amounts accumulation of mycotoxins, which pose great threaten to consumers. In this study, the apples(cv. Fuji, Ralls and Red Star) inoculated with T. roseum and P. expansum were researched. A rapid, sensitive and reliable UPLC–MS/MS method was developed for the determination of T-2 toxin and neosolaniol in the apple inoculated with T. roseum. The influenceof cultivars, storage temperature and parts of apple on mycotoxin accumulation was evaluated. The postharvest diseases and mycotoxins accumulation were controlled by treating the apple fruit with chitosan, citric acid and sodium silicate. The results showed as:1. A reliable and sensitive method of T-2 toxin and neosolaniol was developed. After the extraction from apple matrix with methanol/water(80/20, V/V), the concentrated extracts were cleaned-up by PriboFast M270 columns and then detected with UPLC-MS/MS. Under the condition of optimized extraction and liquid mass, the validity of this method was determined by testing linearity(R2≥0.9995), precision(relative standard deviation≤3.59), accuracy, selectivity(limits of detection(LOD), 0.002-0.005 μg/g; limits of quantification(LOQ), 0.005-0.010 μg/g, respectively)and average recovery(73.48-96.35%).2. The concentration of T-2 toxin and patulin was much higher in susceptible cultivar(cv. Fuji)than in resistant one(cv. Ralls), but NEO was detected in the ‘Red Star’ apple. Room temperature storage was more likely to accumulate mycotoxin than low temperature storage. Meanwhile, T-2toxin, neosolaniol and patulin were found not only in the lesion but also in the adjacent asymptomatic tissue. The concentration showed a trend of decline with increase in distance from the infection point.3. The effects of elicitors, citric acid, sodium silicate and chitosan were studied on suppressing the development of lesion diameters and reducing the accumulation of T-2 toxin and patulin in apple fruit inoculated with T. roseum and P. expansum. The disease diameter of apple inoculated with T.roseum by treating with three elicitors was 85.9%, 81.2% and 72.9%, and the accumulation of T-2toxin was 71.23%, 65.3% and 67.1% when compared with the control, respectively. The disease diameter of apple inoculated with P. expansum by treating with three elicitors was 94.1%, 90.9% and87.1%, and the accumulation of patulin was 71.2%, 65.32% and 67.1%, respectively.In conclusion, a reliable and sensitive method was developed and has successfully applied for rapid detection of T-2 toxin and neosolaniol in harvested apple. Low temperature and resistantcultivar can reduce the accumulation of mycotoxin by maintaining fruit resistance. The elicitors reduce the accumulation of toxins by stimulating fruit resistance.