Designing a barley micro malting system for food safety research
Article authored by Dr. William Hay, USDA-ARS Research Plant Physiologist in Peoria, IL
Article edited by Briana K. Whitaker, USDA-ARS Microbiologist in Peoria, IL
A webinar, featuring this research, was held on Tuesday, January 21, 2025 @ 1 pm CT - watch here!
The USDA’s Agricultural Research Service (ARS) and Bradley University are developing barley micro malting devices that use gaseous plant compounds to stop microbial contamination during malting. Dr. William Hay, a Plant Physiologist with the USDA ARS Mycotoxin Prevention and Applied Microbiology unit (MPM) in Peoria, Illinois, and Dr. Ahmad Fakheri, a Professor of Mechanical Engineering with Bradley University, are leading a team of engineering students in the design and construction of these micro malting devices. This two-year collaborative project seeks to develop and evaluate new treatment technologies to improve the food safety and quality of American beer production.
Mycotoxin accumulation during barley grain malting causes millions of dollars in annual losses for the U.S. malting and brewing industry. Mycotoxins are poisonous fungal metabolites that can contaminate cereal crops, making them unsafe for human consumption. Contamination originates in the field during grain development when crops become infected by fungal pathogens. However, infected grain can continue to accumulate mycotoxins post-harvest during storage and malting. The high moisture and cool temperatures that promote seed germination during malting are also ideal for fungal growth and mycotoxin production. Therefore, U.S. malting companies have adopted a strict standard for barley quality, but even residual fungal contaminates can proliferate rapidly, causing food safety concerns and undesirable product traits like beer gushing.
In response to maltsters concerns, the MPM unit in Peoria began exploring the use of gaseous plant compounds, called “biofumigants,”, to control microbial growth and contamination during barley malting. Critically, these natural biofumigants must not inhibit seed germination or remain on the final malted product. Dr. Hay found that gaseous isothiocyanate compounds from mustard crops control fungal growth (Fusarium) and mycotoxin contamination (deoxynivalenol/vomitoxin) without harming barley germination. Additionally, no residual isothiocyanates were detected on the malted barley after kilning.
This research demonstrated the potential of natural biofumigants to mitigate mycotoxins under laboratory malting conditions, but additional research is required at the pilot scale. The MPM unit is a world class leader in mycotoxin and Fusarium research. However, the unit lacks pilot scale malting facilities and USDA ARS malting laboratories in other locations are not equipped for biofumigant research. To develop these capabilities, the MPM is collaborating with Dr. Ahmad Fakheri and a group of engineering students from Bradley University as part of a Senior Consulting Project capstone class. This project provides students with an opportunity to apply their skills and gain experience by addressing industry engineering needs.
The team is designing and fabricating modular micro malting devices that integrate precise biofumigant treatments while adhering to industry standards for malting conditions (grain moisture content, temperature control, and airflow). By aligning with industry standards, the device will support the development of reproducible and scalable malting methods. Each malting compartment is isolated, preventing cross-contamination of water and air, and allowing for scalable and more rapid experiments.
The micro malting devices will be used to evaluate the efficacy of natural biofumigation treatments on an industrially relevant scale. Dr. Hay and his team hope to develop technologies to integrate biofumigation treatments into existing malting bed airflow channels. This should allow the technology to seamlessly integrate into the malting process without requiring expensive overhauls of current industrial practices. The ultimate goal of this project is to improve the quality and safety of American malt.
