The situation of fungal infection on some medicinal herbs in the form of dried fruits circulating in District 5, Ho Chi Minh City

Abstract

    The aim of our study was to explore fungal contamination in 58 samples belonging to 8 types of dried ripe fruit herbals consisting of Fructus Lycii (Lycium barbarum L. fruit, goji berry), Lycium ruthenicum Murr. fruit (goji nero), Fructus Schisandrae chinensis, Fructus Ziziphi jujubae, Docynia indica Wall. fruit,  Fructus Morindae citrifoliae, Arillus Longan, and Fructus Corni officinalis. We found 21 samples with heavily fungal contamination over 500 CFU per gram , observed in Lycium ruthenicum Murr. fruit, Fructus Schisandrae chinensis, Fructus Morindae citrifoliae, and especially Arillus Longan. According to the Vietnam pharmacopeia (5th Edition), 22 samples were classified to be highly contaminated by moisture. Especially, 6/8 of the Arillus Longan samples presented fungal contamination over 10,000 CFU/g, specifically those in C and E stalls (34 x 10⁴ and 12,3 x 10³ CFU/g respectively). Some samples in A and B stalls had high moisture but low fungus contamination of under 10 CFU/g and some organoleptic irregularities, suggesting the presence of dye, preservatives, changes in pH levels, etc. Yeast appeared in 60 % of the samples such as Fructus Lycii, Fructus Schisandrae chinensis, Fructus Morindae citrifoliae, and Arillus Longan, but they were not identified. There were 35 samples which were contaminated with mold, of which 25 samples were co-infected with yeast. The most predominant mold genus encountered were Aspergillus, Penicillium, and Mucor/Rhizopus. Besides, Trichoderma and some genus of phaeohyphomycosis have been detected in several samples. This result suggested that these samples might be exposed to the contaminant sources, such as being left on the ground during processing or storage.