Flour power (commentary)

It is flour this time, but generally when investigating an E. coli O157:H7 outbreak, if you look back far enough, you will probably bump into a cow.

Just when it seemed that every food that could possibly be responsible for an Escherichia coli outbreak had been identified, taking some of the heat off of beef, the Centers for Disease Control announced on June 1, 2016, that Gold Medal flour produced at General Mills’ Kansas City, Mo., facility was being recalled.

An E. coli O121 outbreak involving 38 victims in 20 states led to the conclusion that the common source was most likely flour from this facility.

When an outbreak involves several states, the CDC always takes the lead in the investigation but works closely with the respective state and/or county health departments and laboratories.

Using Pulsed Field Gel Electrophoresis (PFGE) and whole genome sequencing, CDC was able to ascertain that the outbreak shared a common source, but who would have guessed flour to be that source.

The epidemiologic investigation revealed that of the 38 infected persons, 9 reported eating raw homemade dough or batter and another 3 did the same in a restaurant.

That is nearly one-third of the victims doing what food safety experts have been advising against doing for years, eating raw dough.

Usually the warning was related to contracting salmonella from the uncooked eggs in the dough, but now it takes on a whole new meaning.

Ages ranged from 1 year to 95, and 78% were female. Ten were hospitalized, but none developed hemolytic uremic syndrome which is more commonly associated with E. coli O157:H7.

The bad actor in this outbreak, E. coli O121, is known as one of the “Big Six” non-O157 Shiga toxin–producing E. coli  (STEC), a group that was declared adulterants in raw non-intact beef by the U.S. Department of Agriculture’s Food Safety & Inspection Service (FSIS) on Sept.13, 2011.

If FSIS had not taken that bold move, going against the vocal opposition of the meat industry, one has to wonder if the recall would have occurred.

A bit of research as to the sources of STEC multistate outbreaks reveals that from 2010-2014 there were 34 STEC outbreaks involving more than one state investigated by the CDC as the lead agency.

Almost half (14 outbreaks; 41%) were linked to green leafy vegetables and 24% linked to beef with dairy products (2 outbreaks), sprouts (2) and fish (1) also linked as sources.

59% of the multistate outbreaks were caused by the serogroup O157:H7.

15% of the multistate outbreaks (18 out of the total of 120) from 2010-2014 involving all foodborne pathogens, not just STECs, were linked to imported foods. Mexico was the leading cause of these outbreaks with links to 6 of them.

STECs dwell in the intestines of ruminant animals such as cattle, sheep, deer and elk.  E. coli is normally a dweller in human intestines also, but not of the STEC variety so they are generally good actors that benefit us.

STEC infections caused by E. coli O157:H7 were first recognized in 1982.

Until the CDC created PFGE testing in 1995, and all states now have at least one laboratory doing that testing, STEC infections were generally thought to come from undercooked or mishandled beef.

As pointed out earlier, we know now that row vegetables are the most common source of STEC infections.

The pathogen has to have gotten from a ruminant’s gut to the field somehow, and often that transfer can be prevented or greatly reduced by good agricultural practices such as good staff hygiene, uses of animal waste in growing foods, separation of feed and dairy lots from row vegetables by a scientifically proven safer distance, and equipment sanitation.

Of course, none of this reduces the need for safe handling in the kitchens of our homes and restaurants and not doing things like eating raw cookie dough or milk that are just asking for trouble.

So how did the E coli 0121 actually end up in the flour in Kansas City?

A friend from my USDA days, Nancy Donley who was President of STOP at the time, has said something like;

“When investigating an E coli O157:H7 outbreak, if you look back far enough, you will probably bump into a cow.”

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