Sometimes it feels as if humans are under assault by their food supply. Forever. Food and water borne illnesses have been killing humans since the beginnings of humanity. Sometimes you might think bacteria run the world, and there are as many microbe cells in your body as human and each person interacts with a unique microbiome.
In a world of so many microbes, some of which evolve rapidly, most of the microbes do us no harm, and are often critical to our survival. Some strains are highly dangerous for humans and other forms of life, and some strains only become dangerous in high concentrations.
Ever since people invented cities, these concentrations of people have been home to epidemics caused by concentrations of microbes ultimately eating human food and wastes. It was not until the invention of modern sewer systems and protected water supplies that cities could grow in population from births over deaths. Until then only immigration was able to overcome the high death rates from diarrhea. Immigration from the farms in low density communities that did not have the concentrations of the water borne bacterial illnesses. In other words places with clean drinking water with no one pooping in it.
The birth of cities coincides with the birth of mass scale agriculture. From the fields of Mesopotamia to the miracle of California’s Central Valley is not that big a step. In 1977 I irrigated fields in Idaho with a technology every Mesopotamian farmer would understand. And just as Mesopotamian cities and farming towns mismanaged their fecal wastes, human and animal, resulting in large disease burdens, their only excuse for mismanagement being that they did not have a germ theory of disease and microscopes to see what was happening, the agriculture practiced in 21st Century America (which has no excuse, we know where the crap flows) is still plagued by bacteria, in addition to diseases caused by modern chemicals.
2018 saw outbreaks of two kinds of bacterial diseases. Diseases caused by various strains of Salmonella found in various meat products and diseases caused by Escherichia coli, also known as E. coli, a bacterial species that is common in the intestinal tracts of nearly every mammal. Both cause serious and occasionally fatal bouts of diarrhea and other gastro intestinal symptoms. Children, the elderly, and those with compromised immune systems are most at risk. This past year the strain found in the Romaine Lettuce outbreaks was E. coli O157:H7. This is a particularly nasty strain of E. Coli.
Both of these bacteria, Salmonella and E. Coli, are killed by heat, and therefore thoroughly cooking food kills them and makes the food safe to eat. There are some food borne bacteria that generate toxins that are not destroyed by heat, but that does not apply here.
Salmonella seems to be a problem because in high density industrial animal feedlot farming, poop is everywhere. Meaning Salmonella is everywhere. Cleanliness really counts, but it is expected that there will be some Salmonella in all industrial meats. And therefore cleanliness really counts at home too. Outbreaks this year were from turkey with high Salmonella counts being handled. Not from the post cooking eating. But with the huge demand for food from the growing global middle class we may not be able to raise enough food in the near term without industrial facilities. If you have enough money you can find healthier meats closer to home, but mass demand will be met in ways that make Salmonella outbreaks nearly inevitable maybe even after we truly clean up and green agriculture.
The story about the Romaine lettuce is even more devious. First you have the particular strain of bacteria E. coli O157:H7. In addition to being nasty it appears to be specifically adapted to living on Romaine Lettuce and further attracted to the extra sugars produced as lettuce is cut up for inclusion in prepackaged salads. In both the California Outbreak and the Arizona outbreak the E. coli appears to have reached the lettuce fields via contaminated irrigation water. Irrigation water is simply untreated river water that is channeled into canals and flows for miles and miles until it reaches the field where it will be used to irrigate. Do cattle graze near any of the tributaries? Did dog poop get washed in during the spring melt in the mountains? Did a cat drown? How do you keep everything away from miles and miles of open canals, including some running through farms and some running through cities.
This same irrigation water, this same contaminated irrigation water, is used on a variety of crops, most of which do not cause disease outbreaks. Much of the difference is cooking. Cooking kills E.coli. But we do not cook lettuce. Unfortunately washing seems to have no affect on this pathogen. It does not wash off, and thrives in the wet conditions amongst the leaves. Yikes.
People are going to continue to eat irrigated lettuce. The government is going to continue to provide laxer and laxer standards of cleanliness in the agribusiness world due to the pressure of corporate campaign contributions and lobbying. Bacteria are going to continue to evolve; with new strains taking advantage of all the imbalances we create feeding 8 billion of us. And maybe it is not fair to single out Romaine lettuce, though E. coli O157:H7 has, but if are not going to avoid it entirely, I would cast a wide net checking for disease outbreaks associated with it, as the rate of them seems likely to increase.