How Does Salmonella Get Into Peanut Butter? Bird Feces.

Here’s something you probably don’t want to know, but we’re going to tell you anyway. Scientific American interviewed Michael Doyle, director of the Center for Food Safety at the University of Georgia to find out how salmonella got into peanut butter in the first place. His theory? Bird Feces.

How does salmonella get into peanut butter?

Feces from some animal is a strong possibility. A leak in the roof, for example, caused one of the early outbreaks. How salmonella got into the water that was on the roof, no one knows for sure. Maybe birds, for instance, which accumulate around peanut butter processing plants.

The roasting of peanuts is the only step that will kill the salmonella. If contamination occurs after the roasting process, the game is over and salmonella is going to survive. Studies have shown that salmonella can survive for many months in peanut butter once it’s present. Fatty foods are also more protective of salmonella, so when it gets into the acid of the stomach — which is our first line of defense — it may not get destroyed. Peanut butter, being a highly fatty food, could survive better.

Peanut Problems In A Nutshell [CR]
How does salmonella get into peanut butter? And can you kill it once it’s there? [Scientific American]


Edit Your Comment

  1. springboks says:

    I’m sure the above is only one of many things that happens in the making of our processed foods.

  2. zarex42 says:

    Yep. The goal of zero contaminants in food is unrealistic, so processors just have to make sure contaminants are minimized, and not dangerous.

    No one wants to think about it, but there is all sorts of “gross” stuff in everyday food, but it’s rarely dangerous.

    • sirwired says:

      @zarex42: So true. The idea of avoiding all contamination prior to a product being prepared is completely unreasonable. There is no federal rule or sanitation practice that is going to keep a bird from taking a dump on a pile of peanuts (or potatoes, grapes, carrots, whatever) while they are being loaded into the truck at the farm. There is no trap, screen, or machine that can completely keep rats out of grain silos.

      The most important thing you can do to avoid food poisoning is to wash and/or cook all foods before eating. (A simple water wash almost always suffices for fresh produce.) Also important is to avoid cross-contamination in your kitchen. (i.e. Wipe down the counter with hot, soapy, water after cutting up a chicken.) Once foods are cooked, they must be stored in a way that prevents spoilage or contamination. (This is where PCA screwed up…)

      • TechnoDestructo says:


        I am envisioning a heat and motion sensitive camera guiding lasers to perforate any bird or rodent that comes within 50 feet of the pile of agricultural products. It may not be possible now, but one day…

      • Wormfather is Wormfather says:

        @sirwired: Me, I pee on all my food stuffs. The urine kills the bacteria.

    • Eyebrows McGee (now with double the baby!) says:

      @zarex42: I’ve gotten way more tolerant of standard ickies since I started growing a lot of my own veggies, and discovered JUST HOW MANY bugs are camping out in your average head of lettuce. Frankly I’m impressed the supermarket does so well getting rid of them.

      Let’s not even talk about morel mushrooms!

      • downwithmonstercable says:

        @Eyebrows McGee: I can deal with hearing about gross stuff, but when I grab a head of lettuce and see a beetle or earwig on it, I practically stop eating produce for a while… but if I don’t see it, it’s cool.

        • Pink Puppet says:

          @downwithmonstercable: I take that feeling in a different direction. I get creeped out baaad if I find bugs in my grocery store produce, but it hardly bothers me at all if I got it from someone’s garden locally.

          I recognize that it’s all psychological, but at least I can think that they’re my bugs. Not, like, creepy imported alien bugs of rawr.

          • downwithmonstercable says:

            @Pink Puppet: LOL. I’m on the esame page – I meant if I pick up a head of lettuce in the store. It’s almost like bugs from the garden are organic and natural or something, while the ones in the store are like you said.

        • HogwartsAlum says:

          I can handle the beetle, but earwigs absolutely FREAK ME OUT.

          • TechnoDestructo says:


            Hahah. I had a classmate one day start freaking out in class. He’d been kind of stuffed up that day, and he had just blown his nose. He starts yelling “OH MY GOD! OH MY GOD!” and going around showing people the tissue.

            In it was a great big fat old earwig, writhing around, obviously the worse for wear, but still alive…maybe an inch and a half long.

            It had been stuck up his nose all day. It had probably crawled in there while he slept.

      • outoftheblew says:

        @Eyebrows McGee: That’s why I worry about all the pesticides that must be on all that stuff. So I use a vegetable wash, and hope for the best.

        • Eyebrows McGee (now with double the baby!) says:

          @outoftheblew: Dammit, now you’ve prevented me from ever buying conventional lettuce again! And my organic habit is already expensive.

    • orlo says:

      @zarex42: So untrue. Zero pathological contamination is entirely possible, but it costs money. It takes a commitment towards producing a quality product, which is totally alien to modern corporations. A rat-proof silo is possible as is fixing the goddamn roof when you notice runoff pouring onto food being packaged. If this is too expensive, and testing and disposing of noxious batches is inconvenient, there is a process called pasteurization that was developed a quarter of a millennium ago that will allow corporations to bottle sewage so that it can safely consumed.

      • lemonchar says:

        @orlo: THANK YOU. My President’s Day wish was that this peanut business might cause other manufacturers to wake up and see what happens when you cut corners.

      • Keavy_Rain says:

        @orlo: The law of diminishing returns comes into play here. Its something I learned about in an environmental ethics class.

        Basically you can reduce any contamination to zero but there is a point where you’re spending an extremely large amount of money to remove a minuscule contamination.

        I imagine the same applies here. While it would be nice to have food that is completely free of contamination its also nice not having to work three jobs just to feed myself.

      • sirwired says:

        @orlo: Complete prevention of dangerous pathological contamination is certainly possible. Zero contamination (even ones that would be dangerous in larger quantities) is not possible. There are simply too many opportunities for contamination to enter the system.

        Rats are notorious for their affinity for grain, and their teeth can chew through steel, concrete and iron. (Not quickly, but chew they do.) Extensive use of traps and poison can almost completely prevent infestation of prepared product (which is typically stored in smaller quantities, and where contamination is easy to spot), but not warehouse or grain-elevator-sized storage facilities the size of an oil tanker. (Rats and most of their droppings can be removed during packaging through the simple expedient of sifting.)

        Yes, certainly the PCA episode is shameful and 100% preventable. That said, it is unreasonable to extrapolate obvious errors by the company in storing prepared product into required the prevention of all contamination, especially of unprepared, unprocessed, unpackaged product.

        I’ll repeat this: Dangerous contamination can be prevented, but not all contamination is dangerous, nor is all non-dangerous contamination preventable. (How do you keep a bird from crapping on a field of lettuce? You don’t. You wash the stuff before eating. How do you prevent dangerous organisms from coating a potato, a food that is sold with clumps of dirt still attached? You don’t. You rinse them off and cook them.

        BTW, Not all foods are suitable for pasteurization, nor does it allow you to drink substances with extremely heavy bacterial contamination. That would be canning, not pasteurization. And it’s only 150 years old, not 250.

  3. Anonymous says:

    “Food Defects” are avoidable! Grow your own food, wash it and process it in a clean kitchen without any birds, bugs or rodents. Sound like a lot of work? Check out what the feds ALLOW to be in your food:

  4. Josue Ramirez says:

    oh gross.

    I don’t think I’ll be having anything with peanut butter for another year.

    • smashedpotats says:

      @Josue Ramirez: Man up!

      There are tons of contaminates in the food we eat. Stay away from any canned fruits/vegetables if a little extra scares you.

    • Traveshamockery says:

      @Josue Ramirez: That’s what your immune system is for!

    • trujunglist says:

      @Josue Ramirez:

      The more I think about things like this, the more afraid I am of becoming OCD or something. Imagine if you were worried about contamination all day long. You basically could not use public ANYTHING. For example, you could go to a store and be touching 100 penis’ and vaginas just by opening the door. So that’s out. You can’t really eat at your computer, because the keyboard is fucking filthy from touching 100 penis’ and vaginas when you went to get your subway sandwich… and if you haven’t noticed, they don’t always wear hair nets at subway, and they sometimes forget to separate the non-food handling from the food handling. Yeah, I guess I am kind of OCD for even noticing or thinking about these things at all, but I try to put it into perspective, ya know? These are just the things I KNOW about…

  5. aak7268 says:

    Haberdasher 1: “You got feces in my peanut butter!”

    Haberdasher 2: “You got peanut butter in my feces!”

    Together: “Heyyyyyyyyyy!” (lightbulb effect)

  6. RenRen says:

    If only the American public was not terrified of the prospect of irradiating foods before they hit the distributors…

    I like to dream.

    • Applekid ┬──┬ ノ( ã‚œ-゜ノ) says:

      @RenRen: Yuck… then there’d be even less incentive to keep the food clean to begin with.

      • TVarmy says:

        @Applekid: Yeah, I’m torn on that. It’d get real gross really fast, but the food would also be “safer” in terms of infectious disease.

        Plus, there’s the issue of safety for the workers. In large food processing plants, many of the workers don’t speak English as a first language, so using a powerful piece of equipment like an irradiation machine could be misused due to a language barrier if they aren’t careful to make it extremely safe and dual labeled.

    • snowburnt says:

      @RenRen: Peanut Butter, Salmonella free! Extra skin sloughing!

    • WorldHarmony says:

      @RenRen: irradiation causes the loss of nutrients, unfortunately. These losses add up, considering that we lose nutrients already through cooking or freezing. An additional source of nutrient loss before food even reaches the consumer is not a good thing.

      • RenRen says:

        @WorldHarmony: We’re not THAT nutritionally deprived. Not enough folks eat fresh fruits and veggies. And, yes, there are safety and other concerns.

        Then again, I had to investigate more flu cases so far this year than there were Salmonella cases in the last ten.

        Many flu cases are fatal. Priorities, anyone?

        • ShikhaCadimillac says:

          @RenRen: Pshhh… Right. Priorities are lost on today’s sensationalized media, and therefore lost on our government and the general population.

          Millions of people die each year in the world from Malaria and tens of thousands die from the common influenza virus, but what do we hear about on TV?

          Bird Flu, SARS, eColi, Salmonella, or whatever the ‘Great Scare’ of the day is.

          It’s disgusting. It seems that the only high profile person that gives even a hoot about the millions dieing yearly from Malaria is Bill Gates and his foundation.

      • LandruBek says:

        @AD8BC: Marshmallow fluff? ew gross, HFCS!

    • samurailynn says:

      @RenRen: Mmm… radiation. I think I’ll play Fallout when I get home tonight.

  7. JGKojak says:

    Comment of the day.

  8. JGKojak says:

    “No one wants to think about it, but there is all sorts of “gross” stuff in everyday food, but it’s rarely dangerous. “

    Point is, it IS dangerous– and if there is, say, a roof leak over the post-production area, then that is highly preventable.

  9. AD8BC says:

    During the bird flu scare Glenn Beck did a funny video about avoiding bird feces on his Headline News show. I can’t get videos on the internet at work but google it if you have a chance, it’s hilarious when the bird flying overhead poops on a guy’s sandwich and he keeps eating it (it was actually marshmallow fluff)

  10. B says:

    First they go after our planes, now they’re putting salmonella in our peanut butter. Next, they’ll be poking out our eyes to feast on the delicious nectar within.

    • downwithmonstercable says:

      @B: “As I bit into the nectarine, it had a crisp juiciness about it that was very pleasurable – until I realized it wasn’t a nectarine at all, but A HUMAN HEAD!”
      -Jack Handey

  11. Trai_Dep says:

    Missed marketing opportunity: “Now extra-fortified with essential* minerals” labels.

    * Okay, and some unessential ones too.

    You know, if cats ruled the world, none of this would have happened.

  12. admiral_stabbin says:

    I smell the plot to a perfect sequel of the classic movie “The Birds”…

  13. cametall says:

    So peanut butter is the food of the devil?

    Damn that Planter’s Peanut dude!

  14. jc364 says:

    Am I the only one amused by the picture? Its like the middle bird is saying, “Go find your own peanut plant to poop on.”

  15. pirate_eggie says:

    Never thought my extreme dislike of peanut butter would ever do me any good.

  16. tworld says:

    Ugh, if everyone saw how our food is processed, or got a good look inside the kitchen of their favorite restaurant, we’d all be as skinny as Twiggy.