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Citrinin produced using strains of Penicillium citrinum from Liupao tea

Guo, Weilu, Zhao, Mouming, Chen, Qingjin, Huang, Li, Mao, Yan, Xia, Ning, Teng, Jianwen, Wei, Baoyao
Food bioscience 2019 v.28 pp. 183-191
Penicillium citrinum, citrinin, detection limit, fermentation, growth retardation, high performance liquid chromatography, human health, leaves, liquids, manufacturing, red yeast rice, tea, temperature, water content
The ability of a strain to produce citrinin was analysed in the growth inhibition zone using HPLC and UHPLC–MS. A total of 12 Penicillium citrinum strains isolated from Liupao tea were inoculated onto tea leaves and their capability for citrinin production were studied using different water content (15–45%) and temperatures (15–40 °C). The results provided a theoretical base for the safe manufacture of Liupao tea. Five strains of P. citrinum produced a clear growth inhibition zone with diameters of 11–22 mm. The citrinin contents in the liquid cultures of the 12 strains of P. citrinum ranged from 0.03 to 14.5 μg/mL. The citrinin contents of the teas with initial water content of 15 and 25% and those inoculated with P. citrinum were below the limit of detection during the fermentation. The citrinin content of the teas with initial water contents of 35 and 45% at 25 °C increased rapidly at first and then decreased during the fermentation. Similarly, the citrinin contents of the teas at 15 and 25 °C rapidly increased and then decreased. Meanwhile, P. citrinum was unable to produce citrinin at 35 and 40 °C. The optimum conditions were 45% water and 25 °C, generating the highest citrinin yield of 181 ng/g, which was higher than the limit of 50 ng/g citrinin in red yeast rice that can cause harm to human health. The highest citrinin yield in tea fermented for 50 days was 34.8 ng/g for stored teas with proper conditions. Therefore, storing teas with a low water content and temperature can reduce the content of citrinin.