Assessment of Microbial Quality and Safety, Including Aflatoxin B1, in Buckwheat Flour and Groats

Authors

La Fontaine Bahatsi, University of Nebraska-LincolnFollow

First Advisor

Andréia Bianchini

Committee Members

Jayne Stratton, Devin Rose

Date of this Version

9-2025

Document Type

Thesis

Citation

A thesis presented to the faculty of the Graduate College at the University of Nebraska in partial fulfillment of requirements for the degree of Master of Science

Major: Food Science and Technology

Under the supervision of Professor Andréia Bianchini

Lincoln, Nebraska, September 2025

Comments

Copyright 2025, La Fontaine Bahatsi. Used by permission

Abstract

Buckwheat (Fagopyrum esculentum), a gluten-free pseudocereal, has gained popularity in global food markets for its nutritional value and functional properties. However, despite its health-promoting potential, buckwheat is vulnerable to microbial contamination and mycotoxin accumulation during cultivation, processing, and storage. These factors present significant food safety concerns that remain understudied, particularly in North America.

This study investigated the microbiological quality and mycotoxin contamination of buckwheat flour and groats collected from different suppliers via online sourcing. Samples were collected in two consecutive years (2024-2025). Microbiological quality, including aerobic plate counts (APC), Enterobacteriaceae, coliforms, E. coli, yeasts, and molds, was evaluated using culture-based methods. Significant contamination was observed in buckwheat flour compared to groats. Samples with elevated Enterobacteriaceae counts were subsequently tested for the presence of Salmonella. This study demonstrates that microbial contamination occurs at various stages of buckwheat production, with significant contamination occurring during processing. Furthermore, it highlights the importance of improved handling and processing practices to ensure the safety and quality of buckwheat products.

This study also investigated the occurrence of aflatoxin B1 (AFB1) in buckwheat flour and groat samples. The study focused on developing and validating methods for quantifying aflatoxin B1 in collected buckwheat samples. Fluorometry and high-performance liquid chromatography (HPLC) were optimized and compared, with HPLC demonstrating superior accuracy, precision, recovery (77–99%), and low matrix effect (0.8%) across spiking levels. The validated HPLC method was used to screen commercial buckwheat samples for AFB1 contamination. The findings demonstrate the significance of processing methods and storage conditions in reducing mycotoxin risks in buckwheat-based products.

Advisor: Andréia Bianchini