Organic Processing Vo1.9 #3

When Earthbound started the test and hold program, we were widely criticized. Much of the industry responded with comments like, “The sample size is too small given the natural level of contamination.” “The method will produce too many false positives or negatives.” These reactions justified the prevailing sentiment that testing couldn’t be effective and therefore nothing should be done. But we believed testing was crucial, so we proceeded. Today, Earthbound has amassed nearly a million data points, which is viewed by many of those same skeptics as very important to the advancement of food safety.

Improving Processing Safety. Once the product has tested negative at the raw
product test and hold hurdle, it’s then released into processing, where several en-
hancements have fortified the safety of
their processes. After the leafy greens
have been mixed, they are conveyed
over a metering belt that controls how
much product enters the processing
stream. This helps prevent the system
controls from being overwhelmed by
too much product. Next, the product
passes through a laser sorter, which
scans the product for chlorophyll and
knocks anything out that doesn’t con-

What causes mutations and new strains of pathogens like EHEC and STEC? One theory from the FDA has to do with something called “mismatch repair,” which is like a microbial spell-checker that detects and repairs errors in DNA sequences. When left unrepaired, genes do not function as nature intended, allowing the bacteria to change genetic structure much more quickly and in a more complex manner. According to Thomas Cebula, the lead researcher on the project and director of the Division for Molecular Biological Research and Evaluation at the FDA’s Center for Food Safety and Applied Nutrition, in this state, not only is there a higher mutation rate but the bug becomes more promiscuous and has the ability to rapidly scavenge DNA from other microorganisms and mutate again.

The implication of these very important findings is that it’s possible that DNA from a really dangerous pathogen can be assimilated into the DNA of E. coli. Researchers found that E. coli mutates ten times more frequently than originally believed and this may be why the hazardous strains of E. coli, such as the EHECs and STECs, are increasingly resistant to antibiotics and are more pervasive in the environment. Additionally, E. coli O157:H7 outbreak transmission data suggests that only a few hundred cells can cause illness. It is this extremely low infectious dose that makes prevention of foodborne E. coli O157:H7 infection a special challenge. 3

STECs are defined by the Centers for Disease Control and Prevention (CDC) as organisms that live in the guts of ruminant animals, including cattle, goats, sheep, deer and elk. However, the organisms have also been isolated from poultry, pork and lamb. Approximately 10 percent of the cases of infection by the STEC bacteria progress to hemolytic uremic syndrome (HUS), which is a life-threatening complication that causes acute renal failure, hemolytic anemia and severe thrombocytopenia. CDC reports that there are an

EHEC and STEC—What the HEC(K)?

By Clifford M. Coles

“Researchers found that
E. coli mutates ten times
more frequently than
originally believed.”

estimated 265,000 STEC infections annually in the United States and approximately 36 percent of these cases are caused by STEC O157 and the remainder caused by the various non- O157 STECs. 4 STEC organisms may be shed by an infected person for several weeks after the symptoms have gone away and CDC reports that some people may keep shedding these bacteria for several months. E. coli O157:H7 can be transmitted directly from person to person.

Mitigating Risks on Farms

So how does the organic grower keep STECs off the farm and how do we deal with the worldwide growers that have no idea what the heck a STEC is—nor the wherewithal to prevent STEC contamination?

Domestically, we have developed Good Agricultural Practices (GAPs) that identify the best practices to be used in growing, harvesting and transporting crops and seeds. Porta-Potties are required in the field in numbers that reflect the amount of people on the harvest crew and in accessible locations. Hand-washing stations in the harvest fields along with the liberal use of chlorine on cutting utensils and harvesting equipment is a common practice. Better upfront testing of crops for STECs before they are harvested along with pre- and postplanting farm assessments have been instituted.