Management options, technologies and strategies for minimised mycotoxin contamination of rice

Abstract

Ninety percent of the world's rice is produced and consumed in Asia. Millions of rice producers are resource-poor farmers with a rice area of less than one hectare. Yield increase and the introduction of double-cropping systems have ensured that rice production has kept up with an increasing demand. However, the increased quantities of grain and the second harvest, which is often in the wet season, have increased the problems in traditional postharvest systems. This can be particularly severe in the humid tropics, where post-harvest losses occur because of outdated management practices and technologies, and delays in post-harvest operations. Fungal infestation of rice grains can lead to discoloration, which results in price reductions in most markets. This can also result in rice being contaminated with mycotoxins, which is less visible to consumers. Contamination with ochratoxins, aflatoxins, and other mycotoxins have occasionally been reported in the literature. In the past, this was not seen as a significant problem and the focus was on other commodities such as maize and peanuts. However, recent studies and a massive recall of food products in Japan in September 2008, including sake, shoshu, and rice crackers made from imported rice from China and Vietnam, which were tested positive for aflatoxins, and also for pesticide residues, have renewed interest in looking at mycotoxin problems in rice. Exploratory studies in the Philippines compared best practice post-harvest management with the traditional management practices often used by smallholder farmers and small processors. It was concluded that synthesis of aflatoxin B1 is very likely in suboptimal post-harvest systems, with levels far above legislative limits. This indicates that there might be a considerable mycotoxin problem in rice from smallholder post-harvest operations. Improved post-harvest management options and technologies are available for diversified small-scale post-harvest systems. Small-scale combine harvesters, affordable and simple mechanical dryers and hermetic storage systems can help to avoid delays in the post-harvest chain and thus reduce mycotoxin contamination of rice. The development of strategies to scale out these improved practices and technologies to a large number of smallholder farmers will continue to be the main challenge.

Modeling Growth Rate and Assessing Aflatoxins Production by Aspergillus flavus as a Function of Water Activity and Temperature on Polished and Brown Rice

“…The tropical nature of major rice producing countries in Asia together with conventional postharvest handling of the grains may promote favorable conditions for deteriorating agents such as fungi. Recently, a review on the actual situation of the rice production and mycotoxin problem in Asia has been published (Gummert and others 2009). …”

“…Even polished rice is not far from being exposed to improper storage conditions in less developed countries due to poor infrastructures and limited knowledge and/or financial resources (Toteja and others 2006). Considering the toxicity of mycotoxins and the role of rice in the world diet, little effort has been spent to investigate the current situation and develop preventive measures to control mycotoxin contamination in the poor countries (Gummert and others 2009). …”

Mycotoxin concentrations in rice from three climatic locations in Africa as affected by grain quality, production site, and storage duration

“…The rice value chain, comprising the pre-and postharvest segments, has unit operations aiming at producing premium quality milled rice that is safe for both, human and animal consumption. In each of these segments, the physicochemical, nutritional, and economic value of the milled rice can be reduced by microbial invasions especially in the humid tropics (Gummert, Balingbing, Barry, & Estevez, 2009). Farmer's practices and environmental conditions that enhance insect propagation, microbial proliferation, and mycotoxin production during these production and processing stages include the following: the use of disease-infected seeds, the nonelimination of disease-infected plants during production, poor harvesting, threshing, drying, parboiling, and milling methods favoring grain damage and/or their contamination (Amponsah, Addo, Dzisi, Moreira, & Ndindeng, 2017;Mapiemfu et al, 2017;Ndindeng et al, 2015) and storage of grains in systems that favor the re-absorption of moisture or expose them to high oxygen levels (Fleurat-Lessard, 2017;Magan, Hope, Cairns, & Aldred, 2003), which promote microbial proliferation.…”

Aflatoxins, Ochratoxins, Trichotecenes, Patulin, Fumonisins and Beauvericin in Finished Products for Human Consumption

“…The extrusion grits cooking caused significant reduction of FB1 in all treatments if compared with the not extruded used as control. The use of glucose resulted in a greater reduction (44.8-66.6%) compared to fructose (32.4-52.2%) or sucrose (26)(27)(28)(29)(30)(31)(32)(33)(34)(35)(36)(37)(38)(39)(40)(41)(42).7%) use.…”

“…Gummert et al described the very positive effect dryers had on maintaining rice quality and reducing mycotoxin risk in Southeast Asia [33].…”