Validating Heat-Treated Flour

Many of us have had to resist the urge to lick the bowl of the brownie mix or sneak a bite of cookie dough but many don’t resist the urge. The growth of ready-to-eat (RTE) flour can be traced to multiple food safety recalls, most recently in 2016, when the FDA investigated a multistate outbreak of Shiga toxin-producing E. coli infections linked to large domestic producer of flour. The impetus for these recalls stems from consumers consuming a not-RTE product (flour) prior to the kill step. After months of extensive testing, the pathogens E. coli O121 and E. coli 026 were detected in laboratory samples.

The risk of foodborne pathogens is increasing in grain products. U.S. wheat production is concentrated in the Midwest where livestock and poultry operations are also important to the agricultural economy. Farms and wild animals serve as a reservoir for these pathogens and with such close proximity, Salmonella or E. coli can be introduced into wheat fields and thus into wheat operations.

In his recent newsletter article, David Acheson, MD, founder and CEO of The Acheson Group, he noted that, “Flour has never been considered to be a ready-to-eat food. It is not treated as such in the field, in production, or at the consumer’s home. But with the regular flow of recalls caused by consumer consumption of raw flour, that may be about to change.” Dr. Acheson adds, “Will this impact regulation? Very likely. Eventually. But at the speed that regulation flows, I would recommend that, for both consumer and brand protection, any company selling a raw product to consumers take steps to determine if it is cost effective to add a viable kill step that would not compromise the product, and look for other cost-effective ways to reduce the risk through supply chain and processing controls.”

The grain products industry is adapting to environmental and consumer behavior induced risk. With a series of food illness outbreaks associated with low-water activity foods, the long-held belief that low-moisture foods are not a food safety risk is no longer valid in today’s world. The need to protect consumers and the corporate brand from the increasing risk has created a need to treat flour with a process that applies a kill step as a preventive control for foodborne pathogens like Salmonella or E. coli.

Treated Flour and Pregelatinized Flour

Treated flour is the result of heat, stress, and shear to reduce the risk of foodborne pathogens. Treated flour is used primarily as a RTE ingredient in products containing flour that might be consumed prior to cooking, such as cookie dough, ice-cream additives, mixes, seasoning blends, etc.

Pregelatinized flour serves a nutritional and process efficiency requirement that is also the result of heat, stress, and shear but not categorically enough to be considered a RTE product. The heat, stress, and shear required to create pregelatinized flours is very specific to break down the starch molecules with water and heat.

Pregelatinized flours perform well in cold water applications, thus enabling quicker mixing methods and they can gel without high heat. Pregelatinized flours can improve dough performance, increase viscosity, and suspend ingredients and are used in prepared and frozen products, sauces, many food preparations, baby foods, yeast products, ice cream, etc.

Treating Flour with Thermal Stress

Extrusion and radio frequency (RF) are examples of two processes used to further treat flour and provide a RTE ingredient.

By nature, extrusion is a continuous process where a food material is forced to flow through a die by a combination of mixing, shear force, and/or heat. A versatile technology with origins in the plastic industry, extrusion is a short-term, high-temperature process, used in a wide variety of products including flour, cereals, snacks, pasta, pet food, and livestock feed. When flour is heated by barrel heat, internal friction, and plastic flows of the product, (if validated) this process can be a preventive control step.