Abstract
For decades, mycotoxin contamination has posed a significant threat to food safety and human health while also exacerbating food insecurity worldwide, particularly in Sub- Saharan Africa. In addressing to this challenge, various food processing techniques have been explored to mitigate the harmful effects of mycotoxins in agricultural products, such as cereals, and to reduce the health risks to consumers of contaminated foods. This study aimed at evaluating the effectiveness of nixtamalization, a traditional food processing method, in reducing mycotoxin levels in cereals commonly consumed in South Africa while also assessing its impact on the nutritional quality of processed cereals. Additionally in the study, biomonitoring was performed to evaluate the extent to which degree of human exposure to multiple mycotoxins via consumption of nixtamalized maize by informal settlers of Kliptown, a squatter camp in Soweto. Blood samples were collected via capillary sampling onto a VAMS am during samples collected on Days 0, 2 and 4 and multi-mycotoxins analyzed using Liquid chromatography tandem Mass spectrometry (LC- MS/MS). In addition, knowledge on mycotoxins among the residence was established via a questionnaire. In this study, five mycotoxins were detected in raw maize grains. Nixtamalization was highly effective, achieving a 100% reduction in fumonisin B3 (FB3) and deoxynivalenol (DON), while FB1, FB2, and zearalenone (ZEN) were reduced by 68, 81, and 89%, respectively, demonstrating a drastic reduction (p < 0.05) in human exposure to these mycotoxins via nixtamalization. In blood samples, ochratoxin A (OTA) among the biomarkers of exposure, was prevalent, with levels ranging from 0.04 to 0.15 μg/kg. DON on Day 0 (mean level: 633.33 ng/kg) was detected among study participants and on Day 4, mean level significantly (p < 0.05) reduced to 20.10 ng/kg. The same toxin in urine was found to be 6926.69 ng/kg with a drastic reduction to 611.70 ng/kg. In urine as well, FB1 levels which was not recovered from blood, significantly (p < 0.05) reduced from 3587.25 ng/kg on Day 0 to 1796.90 and 1184.05 ng/kg on Days 2 and 4, respectively. While the study had more female (65.5%) than male participants (32.5%), none of them had knowledge on mycotoxins and their effects although they frequently experienced fungal contamination in food. The lack of knowledge on mycotoxins and degree with which participants are exposed to multiple mycotoxins place them at high risk
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to increased mycotoxin exposure with significant health implications. The high prevalence of mycotoxins observed in this study raises concerns regarding the health of consumers through the consumption of maize and maize by-products in South Africa. There is a need for targeted educational interventions that focus on improving food safety knowledge and practices, particularly in communities with low educational background. This is the first report on the effect of maize nixtamalization on mycotoxin exposure reduction in Africa.
Keywords: Maize, mycotoxins, nixtamalization, LC-MS/MS and Soweto.