Abstract: Edible mushrooms are popular with consumers due to their rich nutrition, tasty and health benefits. Fresh edible mushrooms are usually placed at room temperature in the market. Fresh mushrooms are readily infected with exogenous microbes for their rich nutrition, tender surface structure and lack of a protective structure. In this paper, fresh mushrooms of Flammulina valutipes, Pleurotus eryngii, and Hypsizygus marmoreus were studied. The exogenous bacterial number, species and community diversity were analyzed as a function of storage time at ambient temperature. Results showed that the amount of exogenous bacteria in F. valutipes, P. eryngii and H. marmoreus increased significantly by 29, 417 and 4 116 times, respectively. Besides, the abundance of different exogenous bacteria also changed during the storage period of 5 days, with the highest increase of Pseudomonas spp. in H. marmoreus and decline of Lactococcus spp. in F. valutipe being observed. According to Shannon index, exogenous bacterial diversity of F. valutipe was significantly lower than that of P. eryngii, and H. marmoreus. Principal component analysis results showed that the microbial community structure was similar at different times of storage within each species, and H. marmoreus and P. eryngii showed some similarities, while differences between F. velutipes and the other two species were observed.

Key words: storage period, high throughput sequencing, diversity, pathogenic bacteria, spoilage bacteria