Friday, April 20, 2012

Fertility is the opposite of sterility

I was listening to an interview today.  A huge farm that grows thousands of acres of lettuce, organically, had a big problem.  In 2006 they had a bacterial outbreak in spinach that they produced, and many people got sick, and at least one died. 

One of the people who work for this farm (for this company, ) talked about the fact that they really didn't know how the infection got to their lettuce; that wild pigs a mile away had tested positive for it and that it had been found at a supplier to their farm, but the couldn't figure out how the infection had gotten to their field. 

They went on to say that they had taken all sorts of measures to try to reduce the contamination; they have raked bare dirt areas around their field so that they can detect animal tracks; they don't plant under powerlines because birds like to roost there; they don't harvest anything within (5, 25, 50') of any suspected animal contact, and so on, and at the end, they admitted that there wasn't really anything that they could do.  At some point, unless they grow the food indoors; that would reduce the chance of contamination. 

A few months ago I was talking to a cherry grower in eastern Washington.   He had an equipment trailer that I was interested in, and I drove out to his orchard to take a look at it.   As I looked over the trailer and the tires and thought about it, I asked him about an odd fence that I'd see around some of his cherry trees. 

The fence was high -- maybe 8' high, but it was only around some trees.  Why was that? 

He explained that he'd put it up a few years ago because deer were coming into his orchard to eat the cherry trees, and then explained that he should have taken it down, but he hadn't gotten around to it. 

Why?  Are deer no longer a problem?  "No", he said, "I was required by the company that buys my cherries to exclude all animals from my entire orchard, so I built a fence around my entire property.  "

What do you mean, animals?  Deer -- anything else?  "All animals, " he said "I can't even let my dog run through the orchard; we can't graze cattle there anymore, and in fact we're required to keep records of animal contacts".  

I visited a containment hog farm in Nebraska in the early 2000s; and I was required to change my clothes, shoes, and wash before I could enter.  It was almost an operating room sort of situation.  "We have good biosecurity here! " the farmer explained, and said because the immune systems of the pigs he was raising had not been challenged that his growth rates were between 10 and 15% better than similar pigs with immune challenges.  But the other side of this was that if ANYTHING got into that barn, nothing would have any resistance to it at all, and there would be terrible consequences.  So he scrubbed in and out each day to maintain that sterility. 

In the first two examples here I talked about our food system being modified to remove "challenges" from our diet; sources of contamination that might cause illness or death. 

In the third example I talked about a system that has reached that nirvana of naivete; a confinement pig operation, where none of the animals were bothered by contagion or challenge of any sort. 

When we as a species get to the point where we are too clean, there are unexpected results.  I'm going to point to Polio as a good example of that. 

Polio is an extremely ancient disease; it's been around for a very long time.  At the start of the 20th century we had a population that became the cleanest, most hygienic that the world had ever seen, and Polio was  major scourge.     It struck with more frequency, and with more ferocity, than it had ever before in history.  Polio had mutated...

Or had it?  "Polio is a disease of cleanliness"; it turns out that the virus was present virtually everywhere, and prior to modern cleanliness standards, most children got it very young, as an unexplained fever which quickly left, and left little or no permanent damage. 

When we get too clean we are the pigs in that barn in Nebraska.  We become susceptible to things that people who aren't quite as clean just shrug off. 

It turns out that if your immune system is exposed to challenges at a young age it is much more robust than it is if it is exposed to the same stimulus at a later age, and in fact, it never matches the immune system of earlier exposed individuals. 

Fertility is the opposite of sterility.  The next time you see your child covered in mud, smile and know that asthma is being held at bay.  If you see a little dirt on that carrot -- accept it.

If you see a recall of spinach... well...

Accept fertility.   It's a natural part  of our existence.  Accept the risks that are included, too. 

1 comment:

Joanne said...

Good article Bruce. And too true. There's definitely such a thing as being too clean.

That cherry farmer is no doubt selling to someone/company that is signatory to the Leafy Greens Marketing Agreement, which is something designed to limit risk and liability in produce. A lot of the big distributors are signatoriies and if you're marketing through them you have to sign as well.