Fumonisin in tortillas produced in small-scale facilities and effect of traditional masa production methods on this mycotoxin.

Four small tortilla plants were visited in Cameron County, Texas, where observations were made on their production methods. Samples of liquids and solids were collected at each stage of the nixtamalization process, and the pH was recorded. Samples were analyzed for fumonisin B(1) (FB(1)) using an immunoaffinity column/HPLC method chosen for its sensitivity for FB(1). It was found that production methods were highly variable among the producers visited, with major differences particularly in the amount of lime added and boiling times. As reported by others working in Mexico and Central America, FB(1) was found in some tortillas. This led to studies of the effects of the various recipes and across a greater range of initial FB(1) concentration/damaged corn than has typically been reported. Five initial concentrations of FB(1) were tested using irradiated corn kernels inoculated with Fusarium verticillioides MRC 826 as the source of FB(1). The amount of FB(1) detected in the masa and tortillas decreased as the concentration of Ca(OH)(2) increased, and boiling time had no apparent effect. Unexpectedly, as the initial concentrations were increased in the corn prior to nixtamalization, greater percentage reductions in FB(1) were observed.