Bakers need to be careful about testing their products for soy because a significant portion of wheat flour in America may have traces of soy residue in it. That’s because of agricultural commingling where wheat and soy flour are harvested using the same equipment, stored in shared systems or transported in common trucks or rail cars.

“We don’t think they have to label it in flour, nor do we think it’s hazardous because soybeans are not as potent of an allergen compared to others such as peanut ingredients based on the emerging clinical data,” said Steve Taylor, Ph.D., co-director of the Food Allergy Research and Resource Program (FARRP).

When testing finished products, positive results prompt some bakeries to assume that there is undeclared soy remaining on their shared lines, but often it’s miniscule amounts from commingling.

In 2016, the Food and Drug Administration investigated how low traces of peanut residue were found in soft wheat flour. Such an incident is rare, according to Joe Baumert, Ph.D., FARRP co-director.

“Commingling of peanuts is less likely to occur because the processors use a closed system for harvesting and processing,” he said.

FARRP recommends evaluating commingling on a risk-based assessment to determine if minute traces of allergen residues have a public health and safety impact.

“We don’t advocate labeling for soy residue in flour as this would lead to a decrease in the food choices for soy-allergic individuals and would have minimal effect in increasing food safety,” Dr. Taylor said.