Occurrence of aflatoxins in rice (Oryza sativa L.) produced in Colombia

In order to investigate the presence of aflatoxins (AFs), a total of 120 samples of paddy rice cultivated by the 'irrigation' and 'rainfed' systems in the main rice-growing regions of Colombia were collected during 2017 and 2018. The Association of Official Analytical Chemists accredited standard method, based on high-performance liquid chromatography, was used to detect and quantify AFs (AFB1, AFB2, AFG1, and AFG2). The results showed that, in 2017, the occurrence of AFs in paddy rice from rainfed systems was 43% (range 2.1 to 119.5 μg/kg), while in the irrigation system, it was 16.7% (range 0.1 to 1.83 μg/kg). By 2018, the occurrence of AFs had decreased to 31% for the rainfed system and 2% for the irrigation system. AFs contamination levels were higher in the rainfed system compared to the irrigated system (p<0.05). No AFG1 or AFG2 was detected, irrespective of the cultivation system used. AFB1 was the most prevalent AF in paddy rice, with a global occurrence of 22.9% in 2017 and 8.62% in 2018. At the national level, the prevalence of AFs in milled rice was 50%. Of the positive samples, 62.5% exceeded the maximum permitted value, with concentrations ranging from 10.3 to 93.9 μg/kg. These findings underscore the critical importance of mycotoxins in the context of food safety, emphasizing the necessity for effective control measures within the rice industry. This study is the first detailed report on the incidence of AFs in paddy rice cultivated in Colombia.