Swab tests and plate counts reveal the presence of problem microorganisms.

Combating microbial problems

For Dr. Miller, who has a background in milling and previously taught milling science courses at Kansas State University in the Department of Grain Science and Industry, control starts at the mill. “Keeping mycotoxins out of the food supply is not so much the baker’s concern as the miller’s,” he said. “The mill has the responsibility to reject contaminated grain supplies; the baker wouldn’t see that risk.”

Testing for the presence of these issues involves separate techniques, and their use by millers depends on the bakery customer’s specs and the application for the flour supplied by the mill. “Obviously, baby food would have zero tolerance,” Dr. Miller noted.

The presence of bacteria is determined by plate counts that measure the number of colony forming units (CFU) of aerobic bacteria present in the flour. “Taking this measurement is common practice,” Dr. Miller observed, “and these bacteria are mostly the normal ‘good’ bacteria living in nature.”

Mycotoxins, however, present a different scenario, he noted. The grain is tested at its receiving point. Strict ppm and ppb limits set by FDA determine whether or not the grain will be accepted. “Some years present more problems than others,” Dr. Miller said. “Some growing seasons produce conditions that make it nearly impossible to find mycotoxin-free grains.”

Well-conceived environmental monitoring programs can mitigate problems, but Dr. Channaiah cautioned, “Having an environmental monitoring program does not make food safe. You have to come up with practical actions, and you have to act in a timely manner once you need a correction.”

As the food industry readies itself for regulations under the Food Safety Modernization Act of 2010 (FSMA), the kill step required by law is a simple concept, but a potential hot potato. The kill step is the point in the process that sterilizes the food, killing any microorganisms present.

The miller and the baker are partners in producing grain-based foods, but their circumstances are different. “The miller does not have a kill step, nor is one required by FSMA because the miller’s product — flour — is an ingredient of a further process and not eaten raw by humans,” Dr. Miller explained. “It is only consumed in finished products, and it is generally accepted in the industry that the baker will perform the kill step.

“The microbial load of a loaf of bread coming out of the oven is close to zero,” he continued. “Most are baked off, killed in the process.”

That said, it’s essential that every food manufacturer — every baker, every snack food maker — have a robust hazard analysis critical control points (HACCP) program, according to Dr. Plimpton. In fact, FSMA rules turn the HACCP discipline into an even stronger protocol: hazard analysis and risk-based preventative controls (HARPC). “These controls start with hazard analysis and move from there through inventoried materials and their contribution to the safety of manufactured foods,” Dr. Plimpton explained.

“And while you have to be able to trust the certificate of analysis (COA) you get from your supplier, you also have to test first and test again,” she added.

Avoiding microbial contamination, Dr. Plimpton noted, involves not only how ingredients are stored and handled but also how foot traffic moves through the plant. “There is no food manufacturer out there that wants microbial problems in the plant,” she said.