The use of bioassay to determine the effects of cooking on the toxicity of fumonisins

Authors: Voss, Kenneth; Riley, Ronald; GELINEAU-VAN WAES, JANEE - Creighton University; RYU, DOJIN - Texas Woman'S University; JACKSON, LAUREN - Us Food & Drug Administration (FDA); BIANCHINI, ANDREIA - University Of Nebraska; BULLERMAN, LLOYD - University Of Nebraska; HANNA, MILFORD - University Of Nebraska

Submitted to: Proceedings of the US Japan Joint Panel on Toxic Microorgnisms
Publication Type: Abstract Only
Publication Acceptance Date: 2/23/2012
Publication Date: 3/5/2012
Citation: Voss, K.A., Riley, R.T., Gelineau-Van Waes, J.B., Ryu, D., Jackson, L.S., Bianchini, A., Bullerman, L.B., Hanna, M.A. 2012. The use of bioassay to determine the effects of cooking on the toxicity of fumonisins [abstract]. In: Proceedings of the 11th International Symposium on Toxic Microorganisms "Risk Control and Food Safety." US Japan Joint Panel on Toxic Microorgnisms, March 5-6, 2012, Seiryo, Kaikan. p. 162.

Interpretive Summary: Abstract - no summary required.

Technical Abstract: Fumonisins are mycotoxin contaminants of maize. Fumonisin B1 (FB1), the most common and toxic fumonisin, causes species-specific diseases in animals, is carcinogenic to rodents, and induces neural tube defects (NTD) in LM/Bc and CD1 mouse bioassays. The human health implications associated with FB1 and other fumonisins are uncertain although FB1 is considered a potential risk factor for (esophageal) cancer and NTD in populations that consume large amounts of maize-based foods. Maximum levels for fumonisins in commodities and food products have been identified by various authoritative regulatory groups that are deemed appropriate for protecting consumer health. However, there is emerging concern that routinely used analytical procedures might underestimate fumonisin concentrations in (and therefore potential toxicity of) maize or maize-based foods under some conditions. Reasons underlying this concern include the presence of "hidden" or "masked" fumonisins (those associated with or bound to the maize matrix and therefore not detected by routine analytical procedures) in maize, a lack of understanding about their formation during cooking, as well as the possibility that other unknown fumonisin degradation products formed during processing might contribute to toxicity. To address these concerns, a series of experiments including in vivo rodent bioassays have been undertaken to determine how two commonly used cooking methods affect fumonisin toxicity. First, extrusion significantly reduced FB1 concentrations in fermented grits and reduction was enhanced when glucose (10% wt/wt) was added to the grits before cooking. Nephrotoxicity (as judged by evaluating fumonisin-specific kidney lesions and tissue sphingoid base concentrations) of the grits was significantly reduced by extrusion in a three week rat feeding study. The protective effect was further reduced when extrusion was done in combination with glucose supplementation. A second series of experiments focused on the alkaline cooking method for preparing masa and tortilla products known as nixtamalization. In contrast to FB1, hydrolyzed FB1 (HFB1), which is a major reaction product of FB1 formed under alkaline conditions, did not induce NTD in the LM/Bc mouse bioassay. Analysis of alkaline cooked maize products have provided evidence that a minor amount of FB1-matrix binding (or other FB1-matrix association) can occur during nixtamalization. However, the results of rat feeding bioassays indicate that nixtamalization significantly reduces toxicity. Together, these and other studies have shown that extrusion, especially with glucose supplementation, and nixtamalization are effective cooking methods to reduce the toxicity and potential health risks of fumonisins in maize. They have also provided no evidence that any reaction products or matrix-associated "hidden" fumonisins in the cooked products make a significant contribution to in vivo toxicity.