Dr. Stephen Robertson, Ecdysis Fellow
March 30, 2022
A lot of folks who consider regenerative agriculture, incorporating livestock into their systems, and using livestock wastes as a replacement for synthetic fertilizers have the concern of introducing foodborne pathogens into their produce.
It is a legitimate and logical concern. I mean, those pathogens that cause human illness, like Escherichia (E.) coli and Salmonella enterica, are prominent and normal gut bacteria of livestock (and humans). Spreading animal wastes is certainly spreading those pathogens near your food production systems. If you weren’t concerned about it, I’d be worried you didn’t care at all.
There is a lot more going on, though. Pee and poop are packed with organic matter, nitrogen, phosphorus, potassium, and loads of other plant goodies. Plants have incredible associations with soil microbes (like bacteria and fungi) that help break down waste materials and make those nutrients available to the plants. I dare say, plants WANT the poop.
This cycle (animals eat plants and/or other animals and excrete wastes, bacteria/fungi help further break that waste down, and plants absorb the nutrients necessary for growth) has fueled global life for millions of years. Using waste material to feed plants is very much leaning into natural processes. Soils are built of poop [and poop made from poop]. Whether that poop be bacterial, protistal, fungal, or animal, life breaks down other life into more fundamental components, and rebuilding soils demands inputs of those poops.
So, what about “bad” microbes? First, I’d like to share the opinion that there is no such thing as “good” or “bad” microbes. They just are. They all serve a purpose, and even the ones perceived as “bad” have important roles to play. Do some of them make humans sick? Of course! Should we control them in ways that prevent us from getting sick? Absolutely.
When it comes to pesky foodborne bacteria, much of the control we need is provided by diverse communities of soil bacteria. It’s important to remember that even microbes, being life forms, are competitive for space and resources. They all have ways of helping them win out against others, which often means aggressively preventing others from invading their space (which is precisely the reason why penicillin and related antibiotics exist to begin with). It should be no surprise that science has shown us time and time again that a diverse soil community can prevent the establishment of pathogenic bacteria.
Many conventional agriculture practices kill much of the life in the soil, and soils with simplified communities of bacteria and fungi are wide open to colonization by human pathogens. Space and nutrients with little or no competition. Perfect. In this way, it is more likely that pathogenic bacteria will invade and establish themselves in conventionally managed soils than in those that maintain healthy, diverse soil communities.
Livestock are critical to regenerative systems. You simply cannot attain the full potential of a crop field without livestock integration. If maximizing soil health by supporting diverse communities of microbes is important to fighting foodborne pathogens and livestock are essential to rebuilding soils, maximizing soil health, and supporting microbial communities, then logically livestock integration and food health go hand-in-hand.
Regenerative agriculture says use the poops. Incorporate the livestock. Encourage healthy pant growth while revitalizing and rebuilding soils in ways that plants and microbial communities—truly, entire ecosystems—are evolved to. A healthy and diverse soil will reduce foodborne illnesses far better than a sterile soil ever can.