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 (FB1) using an immunoaffinity column/HPLC method chosen for its sensitivity for FB1. 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, FB1 was found in some tortillas. This led to studies of the effects of the various recipes and across a greater range of initial FB1 concentration/damaged corn than has typically been reported. Five initial concentrations of FB1 were tested using irradiated corn kernels inoculated with Fusarium verticillioides MRC 826 as the source of FB1. The amount of FB1 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 FB1 were observed.