Analysis of Fungal Contamination on Commercially Sold Rice in Puerto Rico

Abstract

Crops and stored grains are susceptible to pathogens that represent a threat to our health. The study presented herein compares the normal surface and endophytic fungal communities present on white and brown rice grains. One hundred grains of each rice variety was analyzed to determine their fungal contaminants and endophytes. Fungi were inoculated on SDA media, and purified in PDA media; morphological characterization was performed followed by amplification of the ITS region using PCR for all fungal isolates. Statistical analysis indicated significant differences between medium brown rice compared to white rice for surface and endophytic communities (p-value £ 0.05). In addition, a higher fungal diversity was found on brown rice grains compared to white rice. This variation may be due to differences in the processing methods used for each rice grain type. BLAST analysis revealed the presence of toxigenic strains of Aspergillus flavus, A.oryzae, Penicillium verrucosum, and P. viridicatum. The study of fungal growth in rice grains can contribute to the minimization of mycotoxin production by its prevention and control; therefore, decreasing crop contamination and human exposure to their metabolites. KEYWORDS: Fungi; Rice; Fungal contaminants; Fungal endophytes