Postharvest Strategies for Deoxynivalenol and Zearalenone Reduction in Stored Adlay (Coix lachryma-jobi L.) Grains

Abstract

Improperly practiced postharvest procedures can pose mycotoxin-related risks in the production of medicinal herbs. As a health food with pharmacological supplements, cereal-based adlay has been broadly used in oriental medical practice. Compared with the standard production protocol, three provisional critical control points (CCPs) in the conventional procedure were identified and assessed for mycotoxin contamination in the adlay from small farms in Korea. Although various mycotoxins were present, the prevalence of deoxynivalenol (DON) or zearalenone (ZEN) was relatively high in the adlay. In terms of drying conditions, field drying in the conventional pathway was associated with more exposure to DON than heated-air drying. Moreover, the DON or ZEN levels in chaff were higher than the levels in the inner grain, suggesting that the hulling process as another CCP would reduce the DON or ZEN exposure. In particular, the DON or ZEN levels in adlay stored for protracted periods without dehulling were very high, but a lower storage temperature of 12°C was not effective at significantly reducing these mycotoxins. In this case, the inner grain was more contaminated with DON or ZEN than the chaff after protracted storage because surface fungi, which produce mycotoxins, can penetrate deep into grain with time. Heated-air drying and nonprotracted storage limited DON contamination in adlay. More importantly, an early dehulling process should be adopted as an easy preventive action to reduce the risk of exposure to DON or ZEN in adlay postharvest. This is monitored as a central CCP for safer production of adlay from local farms.

Fungal Deoxynivalenol-Induced Enterocyte Distress Is Attenuated by Adulterated Adlay: In Vitro Evidences for Mucoactive Counteraction

“…Therefore, in our model, we used 100–1,000 ng/ml DON, which corresponds to in vivo exposure levels (about 0.1–1.0 mg DON/kg food/feed), which is assumed to be realistic within the average contamination level in both food and feed. According to our previous investigation, although the DON contamination levels in total adlay were 0.37–2.55 mg/kg, the bran levels were around 0.4–1.0 mg/kg adlay ( 5 ). Although high levels of trichothecene mycotoxins such as nivalenol and DON (>2,000 ng/ml) significantly influence enterocyte viability through activation of pro-apoptotic processes, ingestion of the realistic milder levels of DON (<1,000 ng/ml) retarded the epithelial cell migration (restitution), representing the initial step in the wound healing process in the gastrointestinal tract.…”

“…Naturally occurring mycotoxins limit the utilization of medicinal materials and introduce potential risks to human and animal health. Fusarium head blight and its toxic metabolites such trichothecenes are present in adlay (family: Poaceae) as a rich source of Fusarium species ( 4 , 5 ). The trichothecene mycotoxins, a group of secondary metabolites produced by sesquiterpenoid fungi, are widely found with high prevalence in cereals, grains, feedstuffs, and indoor air ( 6 ).…”

“…Among the trichothecenes, deoxynivalenol (DON; vomitoxin) is mainly produced by Fusarium graminearum and Fusarium culmorum ( 7 , 8 ), which colonize more than 60–70% of world agricultural commodities, including a variety of cereal-based feed and foodstuffs ( 9 ). DON also frequently spoils grains with medicinal properties, such as adlay, via infection with the mold ( 5 ).…”

“…Depending on the presence of bioactive food components, the net toxicity of DON in the food matrix could be either attenuated or incremented. In particular, contamination with trichothecene mycotoxins including DON in adlay grains frequently occurs because of improperly practiced postharvest procedures ( 5 ). Adlay grains and their components have been shown to possess anticancer ( 25 ), antioxidant ( 26 , 27 ), antiallergic ( 28 ), and anti-inflammatory activities ( 29 – 31 ).…”

Nation-Based Occurrence and Endogenous Biological Reduction of Mycotoxins in Medicinal Herbs and Spices

“…The procedure-based sampling and mycotoxin measurement would provide critical control points for the preventive reduction of fungal growth and mycotoxin production in the agricultural commodities. A recent study on the mycotoxin reduction in the medicinal plant adlay (Job’s Tears) demonstrated that the critical control point-based assessment was efficient to reduce the fungal growth and trichothecene production in the final product of the herbal medicine [ 30 ]. In addition to the diversities in the exogenous compounding factors affecting mycotoxin production in the medical herbs and spices, the quantitation methods should be the internationally recognized official methods of analysis, such as those by AOAC international.…”