Why We’ve Got Salmonella In Our Tomatoes

attack-of-the-killer-tomatoesAfter feeling all smug and superior about eating vegan these last few months (meat recall here, meat recall there), wham! tomatoes are infected with Salmonella. I wasn't planning on writing a post on this topic because it's all over the place, but today, instead of more stories about who's not carrying tomatoes, and what variety is infected, I read an explanation as to why this is happening. So here is the executive summary of the article I read in New Scientist Magazine.

Bottom line, it appears our groundwater is contaminated with animal feces. The water is used to propogate the tomatoes which then act as an "incubator" for the Salmonella.

A recent census of produce outbreaks between 1996 and 2007 counted no fewer than 33 epidemics from Salmonella-contaminated fruits and vegetables. In five of them, tomatoes were the culprit. Cantaloupe melons and sprouted seeds, such as clover and alfalfa, were also common victims. Animal pathogens tend to infect only a limited range of plants.

Yikes! And yet another reason not to eat meat! (Less meat consumed = less production = less groundwater pollution.)

Scientists postulate that since fresh vegetables are increasingly packaged and shipped in centralized locations, nationwide epidemics are becoming more prevalent. Interestingly, "cleaner" produce isn't necessarily the solution either. Harmless bacteria coat tomatoes and other produce, and that could be killed off by more thorough washing. These bacteria compete against pathogens like Salmonella. One lab found that tomatoes coated with a harmless form of a bug called Enterobacter were less likely to test positive for Salmonella. Salmonella seems to like it when there's no competitor.

So, our groundwater is contaminated by animal feces, and our crops are being propagated with this polluted water. Well, if we're processing ten billion animals annually for food here in the US, that's a lot of poop to process! It certainly stands to reason that not all of that poop is being processed effectively. According to the UN Report, Livestock's Long Shadow (pages 140-142):

the most important water-borne bacterial and viral pathogens that are of primary importance to public health and veterinary public health are:

  • Campylobacter SPP
  • Escherichia Coli 0157:H7 (this is responsible for last year's spinach recall)
  • Salmonella SPP*
  • Clostridium botulinum
  • Giardia lamblia
  • Viral diseases (ie - foot and mouth, swine fever)
  • Livestock Parasitic Diseases
  • Cryptosporidium parvum
  • Microsporidia SPP
  • Fasciola SPP

* This is the variety of salmonella which is responsible for the current tomato recall. Salmonella spp is present in 41% of turkeys tested in California and 50% of chickens tested in Massachusetts.

The Sierra Club reports that factory farms produce 500 million tons of animal waste per year.

According to the Environmental Protection Agency, hog, chicken and cattle waste has polluted 35,000 miles of rivers in 22 states and contaminated groundwater in 17 states.

Clearly, we have a problem. If you'd like more information, Livestock's Long Shadow has in depth details on water pollution -- pages 144-162.


  1. You mean *ten* billion animals killed for food each year in the U.S. Which gets me to thinking about the 50 billion (and rising) figure worldwide. As populations in developing countries try to emulate the Standard American Diet, not only will they get more heart attacks, cancer, and diabetes, they’ll also likely get more contamination of vegetables. Our leading “export” may be disease.

  2. We have a backyard garden and are growing organic tomatoes, herbs and vegetables. It’s only in the past year that I’ve considered the thousands of miles our produce travels to get to our tables, spreading poopy germs across the nation.

  3. As a life member of the Sierra Club, I am VERY concerned about factory farms. They are a big problem. What I don’t see emphasized in this story, though, is the larger issue of depleted sources of groundwater.

    All of the other statements are true but we’re finding infection and contamination rates higher because the fecal matter which finds its way into the water table does so at much higher densities but also splashes into less water – thus less opportunity for dilution.

  4. Hi Gary, Thanks for pointing out the error, I’ve corrected it in the post. That’s what I get for writing my posts before bed!
    Yes, it’s really unfortunate that we’re exporting our diet, but there is a pervasive ideology that eating meat = affluence. It’s going to be an uphill struggle to get that thought process changed.

    Hi Bea, Well the media certainly knows who butters their bread. If you’re interested, Livestock’s Long Shadow (link above) goes into quite a bit of detail on how processing both poisons and depletes our freshwater reserves. It’s quite horrific.

    Hi Kendra,
    There are so many facets to this. Eating locally helps, growing your own organic produce at home, buying from the farmers markets… And, eating vegan!

    Hi Alex,
    Scary isn’t it? The bacteria actually mutates on the plant so it’s not the same strain, but it comes from fecal matter, and that fecal matter is in our groundwater!

    Hi Teasas,
    I couldn’t believe it either. I assumed the ecoli/spinach problems last year were some how related to people not washing their hands which was disgusting enough to consider. This is really awful because the extent of the pollution is so much greater.

    Hi Mr. Sustainable,
    No I didn’t talk about the other issues involved with factory farming, simply because this post was about the Salmonella outbreak, and long enough as it stands. The Sierra Club article I linked to touches on this and Livestock’s Long Shadow goes into great detail.

    Hi Elaine,
    Thank you for the link. We’re glad you found the post informative.

  5. Hi David,
    Yup. Just wait until we’ve had a bit more experience with some of the genetically modified crops. I’m not saying they’re all going to be horrors, but I do expect there will be a few problems down the line.

  6. Ok ok, although I am not a vegan, I do agree with not eating so much meat. Actually I don’t eat much meat at all.

    For the health of our bodies, and now obviously the “fruit of the land” we need to back off the meat.

    Thanks for the great info about this salmonella break out.


  7. Lane…. “Livestock’s Long Shadow” – I know it well – and refer many non-believers to it often.

    Kenney: Sounds like you’re almost there….. just a few easy and delicious (and safe) meal replacements and Eureka!…. you’re Vegan!

    And just to throw out a “conspiracy theory” – could it be that it’s not the tomatos at all? Perhaps these many people getting ill have eaten tomato with something….. like a burger, “chicken” sandwich, or other meat product? I distrust the meat industry and government enough to belive it would distort, hide, and mis-inform the public to save themselves from yet another black-eye. Just a thought…..

  8. Hi Kenney,
    Glad we could provide information you find valuable. As for your consumption… that’s your choice. Although we believe in a vegan diet as the solution to a whole host of problems, including food shortages and environmental issues, we do believe that it is your choice what you eat. Ultimately, what we would like to see happen is a reform in the way that animals are treated and a significant reduction in meat consumption overall.

    Hi Bea,
    Between “Livestock’s Long Shadow” and “The China Study” there’s no chance of staying omnivorous, is there?
    As for the conspiracy… well yes, there is. How do you think all that waste gets into the water in the first place? Someone is turning their head!

  9. What a super-interesting article! Thanks so much for explaining this to me…I was wondering how that all worked to get bacteria of this sort in our veggies…

    Wow…it’s a crazy thing that we have gotten ourselves into on our planet…We can be so careless!

    Kimberly Edwards

  10. Hi Kim,
    Yes, we are so careless. I just read something about how much waste were creating by upgrading our computers ever few years…

  11. This is why the FDA will not release the information of where the tainted tomatos are coming from, we learn later that they are grown in Florida and Mexico. Polluted water, polluted land, where does it end?

  12. Hi Teri,
    It may never end. A large part of the problem is we often act in an unthinking manner. We’re all about free trade, sometimes forgetting that the corporations are motivated by the bottom line, not the best interests of the world…

  13. Hi Elaine,
    That is almost unbelievable. The fact that the state department of natural resources is allowing the cafo’s to spray waste onto the fields to help preserve the waste lagoons is frightening. I understand the need to preserve the integrity of the lagoons (it would be far worse for them to collapse). But this doesn’t seem like the best answer either. Thanks for pointing out the story.

  14. In general I have a great dis-trust of the FDA and the news it does (or doesn’t) let the media report.

    Obviously flood waters are filled with icky stuff on it’s own….. add volumes of animal waste and it’s a real mess. The Veterinary Disaster Preparedness and Response Animal Care and Handling TAB F SECTION 5
    “Unsanitary conditions may develop. Enteropathogens, especially Salmonella, can be a problem.”

    I also wonder – (suspiciously) – that perhaps it is in the meat….. and the industry just can’t take another negative hit? There has been some e-coli illnesses prompting a recent ground-beef recall: http://news.google.com/news?hl=en&rls=com.microsoft:en-us:IE-Address&rlz=1I7GGIH&pwst=1&revid=1684643671&resnum=0&ie=UTF-8&resnum=11&ncl=1224101580

    Aren’t the symptoms of e-coli and salmonella similar? And if so….. is it possible for such a switcheroo cover-up to occur?

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