Diversity Assessment of Fungal Contaminants  Along Production Lines in Mushroom Farms

Diversity Assessment of Fungal Contaminants  Along Production Lines in Mushroom Farms

*Ellen Joyce A. Pagoso1,2 and Thomas Edison E. dela Cruz1,2,3

1 The Graduate School,

2 Fungal Biodiversity, Ecogenomics and Systematics Group,

Research Center for the Natural and Applied Sciences, and

3 Department of Biological Sciences, College of Science,

University of Santo Tomas, España Blvd. 1015 Manila, Philippines

Mushroom farming is a sustainable source of income in many developing countries, including the Philippines. However, like many agricultural industries, mushrooms grown on farms are often attacked by fungal contaminants, which could result in drastic economic losses. Therefore, to minimize loss of income among our mushroom farmers, early detection of fungal contaminants is necessary. In this study, we isolated and identified fungi contaminating cultivated mushrooms from two small- and two medium-scale commercial farms in Guimba, Nueva Ecija, and assessed their taxonomic diversity. Our results showed the isolation of 87 fungal isolates belonging to the genera Aspergillus, Penicillium, Cladosporium, Nigrospora, and Trichoderma from 40 contaminated fruiting bags. The extent of fungal contamination ranged from 25% to 100% of the whole fruiting body bags. Between the two farm types, small-scale mushroom farms had a higher number of fungal isolates. To detect the possible sources of these fungal contaminants, we evaluated the fungal load along the different areas of the mushroom production lines using 3M Yeast and Mold Count Plates. Our results showed the highest average fungal load in the fruiting bag storage area (325 CFU/5cm2), followed by the cultivation area (268 CFU/5cm2), the fruiting bag preparation room (219 CFU/5cm2), and inoculation room (90 CFU/5cm2). Between the two farm types, small-scale farms accumulated a higher average fungal load (247 CFU/5cm2) than medium-scale farms (126 CFU/5cm2), indicating better sanitation practices. Our study identified the key areas (storage and cultivation areas) along the mushroom production lines where sanitation practices should be strictly observed to prevent fungal contaminations of cultivated mushrooms.