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Consumers need wake-up call about potential dangers of flour



She’s in the kitchen happily making some chocolate chip cookies. Happy because her family loves them but also happy because she loves nibbling on some of the raw cookie dough. It’s something she’s done ever since she was old enough to start baking.

When a friend advises her that the flour in raw cookie dough can contain dangerous bacteria that can get her sick, she shrugs off the advice, saying it’s one of the pleasures in life she doesn’t intend to give up. Besides which, she tells her friend, she’s never had any problems with eating raw cookie dough, nor has anyone in her family or anyone she knows.

In another kitchen, a mom is making a cake for her son’s birthday. Once she’s done beating the batter and pouring it into the cake pans, she hands the bowl and mixing spoon to her son and daughter, who happily lick them clean. She would be surprised indeed to learn that this time-honored baking tradition could actually get them sick, especially since her mother always let her and her sister lick the spoon and bowl when she was finished beating the batter.

Her friend chuckles and tells her that she always leaves some extra batter in the bowl so there’s more for her to “lick clean.”

But wait. What about this warning from the FDA: “Because uncooked flour can be contaminated with a variety of disease-causing germs, including E. coli, Salmonella and Listeria, eating uncooked dough or batter, whether for bread, cookies, pie crust, pizza and tortillas can cause illness.”

Or this warning from James E. Rogers, director of food safety research and testing at Consumer Reports: “Consumers should resist the temptation to eat raw dough or batter. “Bacteria that can cause foodborne illness can lurk in both uncooked flour and raw eggs.”
A look at just some of the recalls of flour are proof of that.

Cookies figured in a 2009 E. coli-related recall when raw, prepackaged Nestle cookie dough were linked to food-borne illnesses in 77 people. That likely happened when some of the people baking the cookies nibbled on some of the raw cookie dough. In that outbreak, 35 people had to be hospitalized and 10 developed kidney failure. At first, the likely culprit seemed to be eggs. But researchers subsequently pointed to flour. That led Nestle to switch to heat-treated flour for its refrigerated cookie dough.

In 2015, General Mills recalled 45 million tons of flour and other companies issued secondary recalls because they used the flour to produce their foods. Included in the recall, were products ranging from bread and pancake mixes to meat and poultry products. At least 46 people, 13 of whom needed to be hospitalized, were sickened. Three main brands of flour: Gold Medal, Signature Kitchens and Wondra, were named.

Just recently, as of July 11, 2019, flour contaminated with E. coli O26 sickened 21 people from 9 states.

Illnesses started on dates ranging from Dec. 11, 2018 to May 21, 2019. Ill people ranged in age from 7 to 86 years, with a median age of 24. Seventy-one percent of ill people were female. Of 20 people with information available, three, for roughly 15 percent, were hospitalized. No deaths were reported.

Epidemiologic and laboratory evidence, supported by product distribution records, indicated that flour was the likely source of this outbreak.

Trusted brand names, among them, Gold Medal, Pillsbury and General Mills were named in the recalls. In the case of General Mills, the recall was based on the potential contamination with salmonella.

What’s going on here?

As a starter, flour is made from wheat, and wheat fields attract all sorts of critters among them insects, wildlife such as deer and rodents, stray livestock, and even birds that fly overhead to get from place to place.

As the FDA puts it: “If an animal heeds the call of nature in the field, bacteria from the animal waste could contaminate the grain, which is then harvested and milled into flour.”

And therein lies the problem — at least when it comes to food safety. Animals can carry E. coli, salmonella, listeria and other pathogens that can contaminate human foods via a variety of routes.

Driving along country roads in wheat country is proof enough of how much potential there is for bacteria from livestock and wildlife to contaminate the wheat. The fields, a picture-perfect photographer’s dream, often extend for miles and miles.

Yet many people don’t equate the flour they use to make such products as breads, cakes, muffins and tortillas with the wheat fields they may have driven past.

But isn’t wheat cleaned?

From the wheat field to the finished product, flour, for the most part, is not treated to kill microbiological bacteria such as E. coli, Salmonella and Listeria. That, even though food-safety steps such as making sure the equipment and trucks transporting the product are clean and that workers are trained to follow basic food-safety practices.

Once the fields are harvested and the wheat kernels are taken to a mill, they are cleaned, milled and then sifted. The goal of this process is to remove the outer layer of the what kernel and grind the interior endosperm into flour.

Cleaning the wheat comes down to removing unwanted objects such as stones, pieces of metal and wheat kernels with color differences.

In other words, milling is a simple mechanical process that doesn’t address microbial pathogens, said Ronald Burke of Ardent Mills. And General Mills warns people that flour is made from wheat that is grown outdoors where bacteria are often present.

Kent Juliot, Ardent Mills vice president of research, quality and technical solutions, said during a webinar that in addition to wheat being subject to possible incursions from animals and birds, the previous use of crop land is part of the food-safety equation.

Even so, contamination rates are extremely low, he said.

CDC, meanwhile, warns the public that flour is a raw, uncooked product.

Doesn’t look raw to me

But flour doesn’t look “raw” to most consumers. In fact, flour, especially white flour, looks highly processed. After all, by the time it gets to the end user, it’s looks “pure” and is so fine it can even be sifted.

Yet, even with the potential for pathogens to be in it, raw flour rarely gets people sick for one simple reason: it’s very rarely eaten raw.

Instead, it’s added to other ingredients to make bread, pie crust, cookies, and cakes, for example. And it can be boiled, as in the case of dumplings or noodles, or fried as in the case of breading for fish and other foods.

Pure and simple, cooking raw flour puts any pathogens that might be in it through a “kill step” they can’t survive. As long as it’s cooked, it’s safe.

“When it comes time to cook, make sure to cook food thoroughly,” Consumer Reports Rogers says, because cooking will kill the bacteria. And carefully clean any prep areas, dishes, and utensils used in cooking. Wipe raw flour off countertops, and wash dishes with warm, soapy water or run them through a hot dishwasher cycle. And don’t let kids make homemade play dough with raw flour, either.

What about taking samples?

If flour can contain dangerous bacteria that can get people sick, why not take samples of the flour before it’s sold.

In a special report from Ardent Mills Food Safety Team, testing of a production lot doesn’t guarantee the entire lot is free of foodborne pathogens.

Pointing out that production lots are usually very large, the report says that only a fraction of a lot can be tested.

Pathogens generally are not homogeneously distributed throughout the lot,” says the report. Instead they tend to clump together in groups. That means that a sample that is tested for the pathogen can yield a negative result, when other areas in the lot may contain pathogens.

Can’t you zap flour with heat

As in the case of other foods, using heat to kill bacteria can make flour safe. But considering how much flour is used each year — the sheer volume of it — the actual process of heating up that much flour on a regular basis staggers the mind.

Then, too, there’s the cost, estimated at from $8 to $12 per hundred weight. Industry officials say that for more than 90 percent of the flour that’s milled in the United States, heat sanitation would not be necessary simply because flour is usually used in foods that are cooked. Exceptions would be for certain uses of flour such as spice coatings for snack chips and dehydrated infant foods.

Even so, some say that in cases such as refrigerated cookie dough mix, ready-made pie crust, and heat-and-bake rolls, heating the flour in those products would be a plus for food safety. But again, that’s because some people might nibble on those foods before cooking them, therefore putting themselves at risk of getting sick from pathogens that might be in the flour.

One of the high costs associated with heating flour is that dry products such as flour take a long time to sanitize. Compared to killing microbes in water, which takes only a matter of seconds when the water is heated to 160 degrees, it could take hours to heat the flour up to a temperature that would kill the microbes.

Heating flour can also change or destroy the properties in the flour that makes a loaf of bread rise and hold its shape.

The goal of heat treating flour is to reduce the build-up of pathogens during the shelf life of the flour. First patented in 1970, the process of heat treating flour is seen as a safer alternative to chlorination and irradiation. At this point, consumers don’t like the thought of irradiating food.

One company’s solution

Ardent Mills, a flour milling and ingredient company, has come up with a solution for flour used in ready-to-cook or ready-to-eat foods.

The company says that its SafeGuard treatment effectively kills pathogens (up to a 5-log validated pathogen reduction) and yet maintains the treated flour’s natural flavor, color, absorption, appearance and gluten functionality (which causes bread to rise and maintain its shape).

And while there have been options for treating flour for a long time, they weren’t widely adopted because of the way they affected the taste of the flour and the way the treated flour functioned when being used in baked, or other, products.

In contrast, the company says that SafeGuard-treated flour can be used in products such as refrigerated biscuit and cookie dough, pizza crusts, frozen doughs, cereals, retail packed flour, brownie/cake mixes and ready-to cook meals.

And in a first for the industry, it has also made SafeGuard flour available in bulk.

Don Trouba Sr., director of Ardent Mills’ Go-to-Market, told Food Safety News that the company can support a lot of volume. He also said the company expects to be “very competitive” thanks to the company’s production capabilities and farmer network.

Taking a holistic approach to providing “safe” flour, the company also takes all aspects of delivering Safe-Guard flour products to the customer into account. This includes cleaning and sanitizing spouting and bins, using a process that exceeds common flour-milling standards. And the company’s fleet of trailers are designed with no obstructions that could harbor microbial growth.

More positive steps

Low concentrations of microorganisms in agricultural commodities like wheat is common and complete removal is a challenge, said Kantha Channaiah, Director of Microbiology at AIB International, an information transfer center for bakers and food processors.

To help food manufacturers using flour as an ingredient validate their kill step to control potential pathogens, AIB International has partnered with the American Baking Association, The University of Georgia and Kansas State University to develop free kill step validation procedures for ten bakery products: hamburger buns, 100 percent whole wheat multi-grain pan bread, basic round top cake muffins, nut muffins, crisp cookies, soft cookies, yeast-raised doughnuts, cheesecake, flour tortillas, and fruit-filled pastry.

In addition, five of the kill step validation research findings have been published as open access in high impact peer-reviewed journals so this information is available to all bakeries. These kill step calculators can be downloaded from AIB International’s website for free and are available both in °C and °F. To date more than 5,400 kill-step calculators have been downloaded.

The best, and cheapest, way of all

In the end, it’s the consumers who can do the best job of protecting themselves from getting sick from foodborne pathogens that might be in the flour and products with flour that they bring home.


The solution is simply to make sure they cook anything that contains flour.

Consumers can’t count on labels to warn them if they should or shouldn’t eat any products that need to be cooked first. Some companies, including those that sell boxed cupcake, pancake and cake mixes, haven’t started using warning labels yet. Others have labels that are so small it’s hard to read them even with a magnifying glass. Some, however, do have labels that are obvious enough for customers to notice.

And most bags of flour have warnings that flour is a raw product and should be cooked.

Quick tips from FDA for safe food handling of flour

•Do not eat any raw cookie dough, cake mix, batter, or any other raw dough or batter product that is supposed to be cooked or baked before it is eaten.
•Follow package directions for cooking products containing flour at proper temperatures and for specified times.
•Wash hands, work surfaces, and utensils thoroughly after contact with flour and raw dough products
•Keep raw foods separate from other foods while preparing them to prevent any contamination that may be present from spreading. Be aware that flour may spread easily due to its powdery nature.
•Follow label directions to chill products containing raw dough promptly after purchase until baked.