Microorganisms present on freshly-harvested rice include yeast, molds, and bacteria. Of these, mold contamination typically poses the greatest threat in the rice industry because under certain stressful conditions of temperature, relative humidity, and rice moisture content, some molds may produce very toxic substances known as mycotoxins. Some mycotoxins, such as aflatoxin, are known carcinogens that pose severe health hazards to human and animal consumers. The mitigation of mold growth, and mycotoxin development, has become a top priority for the rice industry. Improper drying and storage of rice encourage molds to grow and potentially leading to mycotoxin production. This study is a part of a two year long of survey aimed to determine the effect of various factors including rice cultivar, growing geographic locations, and harvest time on the prevalence of microorganisms on rough rice. Specifically, the total (ground sample) and surface aerobic plate count (APC) and mold count on freshly-harvested, long-grain hybrid (XL723 and XL753), long-grain pureline (CL152 and RoyJ) and medium-grain (Caffey and Jupiter) rice cultivars grown at four Arkansas locations (Stuttgart, Rohwer, Colt and Keiser) were obtained in 2013. The same varieties were planted in the same locations for repeating the experiments in 2014. The 2013 study determined that geographic location where rice was grown had a significant effect on the level of microbial contamination on the rice kernels at harvest. As much as 1.5- and 3.2-fold total APC and mold count were observed in rice harvested at Rohwer compared to Keiser. Samples of rice harvested at Keiser tended to have the least microbial loads followed by those from Colt; samples from Stuttgart and Rohwer, the southern-most locations, had the greatest microbial loads. These findings could benefit the rice industry by helping to develop effective strategies for drying, storage and/or decontamination of rice, thereby helping to prevent mycotoxin development.

Mold population on freshly-harvested rice and factors affecting prevalence

249th National Meeting (2015)

The official archive and repository for all ACS Meetings & Expositions abstracts and select posters or presentations.