Most strains of E-Coli are harmless and commonly inhabit the intestines of humans and animals. But bacteria are constantly evolving as they struggle to survive in constantly changing environments and somewhere along the line a particularly vicious strain evolved in the gut of ruminant livestock such as cattle, deer goats and sheep.
Known as E-Coli O157:H7, it has made its most recent appearance in romaine lettuce from California, but it was first identified in 1982 when contaminated hamburgers caused an outbreak of bloody diarrhea. It hit the big time in 1993 when undercooked burgers from a fast food restaurant sickened 600 people and caused the death of 4 children and again in 2012 when tainted beef from an Alberta food plant caused the largest recall of meat in Canadian history.
How is this get into the food system?
Roughly half of all cattle shed E-Coli O157:H7 in their feces and contaminate their hide as they romp through feedlots. When the hides are stripped off after slaughter, the bacteria can be transferred to the meat.
The practice of “jaccarding” meat has facilitated the distribution of bacteria into the cuts. This is tenderizing meat by piercing it with a series of needles and very sharp blades to shred the connective tissue. This allows for a more complete penetration of marinades and reduces shrinkage and cooking times. It is not hard to see why this appeals to suppliers. It makes meat “butter tender” and restaurants, caterers and retailers can satisfy customers with cheaper cuts of meat, but it also means exposing us to some nasty bacterial such as E-Coli O157:H7.
You can yourself by ensuring your meat reaches an internal temperature of 70 degrees C. At this temperature the bacteria cannot survive and release their toxins.
But this is not the only way we pick up nasty bacteria. In the United States a little girl died from a hamburger she didn’t even eat when she planted a kiss on the forehead of her infected grandfather! Another youngster became ill from E-Coli O157:H7 at a petting zoo.
And meat is not the only way we can pick up E-Coli O157:H7. There are more outbreaks caused by water than meat. The outbreak in 2000 in Walkerton, ON, where 7 people died and 2000 became infected is an example. This one was traced to manure for nearby farms polluting the water supply.
We have seen outbreaks caused by spinach, unpasteurized apple juice and spouts. Since manure is commonly used as a fertilizer, and fruit or vegetable that has been exposed, particularly if eaten raw, is a hazard.
Obviously, it is really important to wash all fruits and vegetables really well – even cantaloupes because bacteria on the skin can be transferred to the edible portion when cut with a knife. This is not fear-mongering. In 2011 33 people died after eating cantaloupes contaminated with listeria monocytogenes.
And there isn’t space here to talk about fish from China which are partly fed on feces from pigs and geese, shrimp farmers in Vietnam who use ice made from bacteria laden water, or grape tomato pickers who wipe their hands on their pants after answering nature’s call in the field.
Still worried about smart meters giving off dangerous radiation, artificial sweeteners, or trace chemicals leaching out of water bottles?
Source: Schwarcz, Dr. Joe, Monkeys, Myths, and Molecules, ECW Press, 2015