Cereal Grains Testing: Here Are Some of the New Methods Emerging for Rapid Detection

A successful business relies on developing and maintaining consumer trust and confidence in the products they buy. For food manufacturers, building this trusting relationship is even more essential, given the primary importance of food to health and well-being. A product contaminated with microorganisms or toxins that may cause foodborne illness can taint consumer confidence far beyond the product recall.

As a staple ingredient in many food products, cereal grains play a prominent role in the food supply chain. Corn, wheat, barley, rice, oats, rye, millet, and sorghum are the main cereal grains used worldwide as the raw materials for many food products, such as flours, cornmeal, breads, pasta, breakfast cereal, cakes, and tortillas, and for beverages such as beer. Over the past 50 years, worldwide production and yield of these grains has increased to meet the needs of a growing population.

Given the critical and growing reliance on these grains worldwide, ensuring their quality and safety is vital for a strong and reliable food supply chain. The safety of these grains has come under particular scrutiny over the past years due to outbreaks of foodborne illness and recalls attributed to contaminated wheat flour. A 2019 study, published in the Journal of Food Protection, was conducted to assess a baseline level of contamination of pathogens in more than 5,000 raw wheat samples prior to milling and found the prevalence of Salmonella (1.23% of the samples), Escherichia coli (0.44%), and Listeria spp (0.08%) was sufficiently high to indicate a risk for foodborne illness. Along with the health risk, the investigators underscored the potential subsequent loss of revenue for food manufacturers, and a subsequent dent in consumer confidence (J Food Protection. 2019;82:1022–1027).

Understanding the ways in which cereal grains can be contaminated, the types of tests used to mitigate that risk, and gaps and vulnerabilities that persist in ensuring the safety and quality of cereal grains is important for food manufacturers, who must know their food supply chain. “Knowing the origin of the bulk commodity and understanding the processing interventions used by the supply chain to ensure food safety is important, as you can predict some of the quality and safety defects that might occur,” says Douglas L. Marshall, PhD, CFS, the chief scientific officer for Eurofins Microbiology Laboratories in Fort Collins, Colo. “Testing for both desirable quality attributes and for detrimental food safety hazards improves trust in the supply chain and keeps everyone honest.”

Newer Tests for Safety and Quality

Infectious microorganisms such as Salmonella and E. coli are considered major types of biological hazards to food safety associated with grains. Mycotoxins are another type of biological hazard. Along with these, cereals can also be contaminated by chemical and physical hazards (See “Table 1. Potential Contaminants of Cereal Grains”).

Much of the testing for safety of cereal grain is focused on biological contaminants, as these can occur throughout the grain supply chain—from crop growth through harvesting and post-harvesting drying and storage—and may directly affect the quality and safety of the grains used for milling and food production.

“[Cereal grains] are biological materials, living and breathing materials that continue to respire after harvest,” says Gerardo Morantes, PhD, director of food safety at Plymouth, Minn.-based Bühler, a food processing and manufacturing technology group. “Best agricultural practices, weather events, and supply–demand cycles will have an effect on every single crop produced.” Food processors, he adds, should keep this in mind when sourcing these grains, as the quality and food safety challenges faced throughout the food supply chain are directly related to these factors.

Dr. Morantes describes mycotoxins as a universal hazard addressed by all supply chains worldwide. More recent attention and allocation of resources, he says, are focused on infectious microorganisms, such as Salmonella, to better understand alternatives in risk mitigation to prevent foodborne outbreaks such as those recently caused by contaminated raw flour.