How Unscrupulous Food Manufacturers Manipulate Lab Tests

In yesterday’s Peanut Corp. post, our commenter microguy07828 left a detailed explanation of how food manufacturers sometimes play dirty when it comes to getting the lab results they want on a product. We though it deserved more visibility in light of yesterday’s accusation that the Peanut Corp. of America knowingly shipped tainted peanut butter. As microguy07828 puts it, it “happens more often than you would think.”

As someone who has worked in Industrial Microbiology for over 16 years, I can tell you that the situation described here happens more often than you would think.

The main goal of any manufacturing plant is to get the product out the door, so that they can get paid by their customer. Some manufacturing plants will do whatever they can to get microbiologically failing product to market and cover their butts in the process. From my experience, some of the most common tricks dishonest manufacturers try to pull are as follows.

1) Test to Compliance – Microbiological contamination is often not evenly distributed throughout a product. That means that it is possible that if you retest a sample, test another container or another part of the batch, you may not pick up the objectionable organism. If you are testing for overall bacterial or fungal count, it is possible the count on the retest may be lower. Some companies with failing products will continue to send in samples of the same product until they get passing data. They then destroy all of the failing data and are left with a lab report showing that their product is acceptable.

2) Combining Failing Batches with Passing Batches – If a batch is failing for overall bacteria or fungal count, some companies will blend the failing product into passing product to dilute the microbiological contamination to acceptable levels. Lot numbers for the product are then altered to cover their tracks. They then destroy all of the failing data and are left with a lab report showing that their product is microbiologically acceptable.

3) They Purposely Mislabel Samples – If a product fails microbiological testing, some companies will remove the failing product from the sample package and substitute passing product. Now the sample that is sent to the lab has the failing product’s lot number on it, but the sample material inside is passing product. Once the testing is complete, the company receives a lab report showing that the failing product passed testing. They then destroy all of the failing data and are left with a lab report showing that their product is acceptable.

4) They Use a Different Laboratory – All contract microbiology laboratories are not created equal. They run the gamut from a state-of-the-art building with tens of thousands of square feet of work space to a mom and pop operation operating in a two room suite in an office complex. The quality of work these laboratories perform and the reliability of data they produce can vary greatly. If a product is failing at one laboratory, some manufacturers will just send their samples to other laboratories until they get results that they like. The big question is always “Does the manufacturer want the best quality data or do they want passing data?” The truthful answer is that it depends on the customer.

5) They Use Their “Alternate” Laboratory – If I told you that there were microbiology laboratories out in the world that accepts samples, never tests them and then issues passing reports, would you believe it?

6) They Mislead Their Microbiology Laboratory – Sometimes companies will request that their microbiology laboratory change lot numbers on reports, claiming they mistakenly wrote incorrect lot numbers on the incoming sample submission sheets. The microbiology laboratory may innocently and unknowingly provide documentation that allows failing product to ship.

7) They Bully the Microbiology Laboratory – Sometimes manufacturers with failing product request that the microbiology laboratory provide them with a report indicating passing data. Sometimes they remind the laboratory of how much revenue they generate for them. They even may threaten to pull their business is the microbiology laboratory refuses to comply. Money can be a powerful motivator.

8) They Find Another Laboratory – If the microbiology laboratory a manufacturer is using refuses to cave in and help them cover their tracks, the manufacturer may just find another laboratory that will “play ball” with them.

Now my disclaimer: What I have listed above represents my opinion and experience. The vast majority of manufacturers and microbiology laboratories are honest and work hard to do the right things. However, money is a powerful motivator. With product batches that can be worth tens or even hundreds of thousands of dollars, some rouge companies will do whatever they can to prevent product loss. Some are even willing to put the health and well-being of the public at risk.

I do not mean in any way to imply that The Peanut Corporation of America engaged in any type of wrongdoing. Everyone is presumed innocent until proven guilty. I have no doubt that the FDA will determine the root cause of this situation and take any necessary corrective action.

(Photo: adamjtaylor)


Edit Your Comment

  1. AlteredBeast (blaming the OP one article at a time.) says:

    I am now afraid to eat anything.

    Thank you.

    • OmniZero says:

      @AlteredBeast: Seriously. You don’t know which companies use these sneaky tactics. Maybe I’ll have to get that UV Water Purifier and use it on all my food. If that isn’t strong enough I’ll throw my food in a tanning bed.

  2. mdoublej says:

    I think China was saying they want some peanut butter!

  3. boomersix says:

    Amen to that. Im growing my own from now on. Looks like I’ll be hungry till the fall….

    • ceez says:

      @boomersix: good idea, but are your seeds safe?!??! god know where they came from….

    • polymer girl says:

      This is a great reason to join a CSA. With community supported agriculture, you have a relationship with the farm and the people growing your food. You end up eating more healthfully, and locally. When you know the farmers and they know you, there is a much better chance that they aren’t going to screw you over with tainted food.

  4. Tom_Servo says:

    Very interesting.

  5. nataku8_e30 says:

    One of the advantages of home ownership that’s often overlooked is the ability to grow some of your own food. Sure, you won’t be able to grow enough to live off of completely, but if you could reduce the amount of groceries you buy by even as much as 25%, there’s that much less risk you’ll be exposed to sub-par food. Making things like bread from scratch (buying flour, yeast, etc…) is also a good way to avoid the risks of processed foods and heightened levels of preservatives.

    • Josh_G says:


      I could grow enough food to live off of completely, but if I did I would pretty much have to quit my job or at least switch to limited part-time. Add in canning and preserving the crops all of that food raising would take up massive amounts of time throughout the year.

    • Yan Grinshteyn says:


      I’m almost certain that people who rent can also make their own bread.

      • nataku8_e30 says:

        @Yan Grinshteyn: Yan – I apologize for not creating a separate post saying “also, you could make bread from scratch!” Clearly, it is only possible to express a single thought in a single post, so I must have meant that you need to own your own house to be able to bake bread…

    • floraposte says:

      @nataku83: Of course, home canning used to be the big source of botulism, so there’s still that to look forward to.

      • jamar0303 says:

        @lemonchar: But people pay money for botulism these days, don’t they? Not that I would ever pay money to have that injected into my face, but lots of rich vain women do.

    • magic8ball says:

      @nataku83: Well, I tried to grow a peanut-butter tree in my back yard, but it didn’t work … maybe I over-watered.

    • BrazDane says:

      @nataku83: I don’t mean to scare anyone, but before you lay out a big vegetable garden, check what is in the ground first. Did the previous owner store an old car leaking oil and fuel on this spot? Were the remains of a repaving of the driveway stored here (esp. bad if it is old asphalt)? Did the old owner use to do his weeding with old motor oil – seriously, back in the day my dad told me how his dad used waste oil to weed his driveway – back before environmental conscience and knowledge about chemicals reached the general public.
      I am not saying you need a lab test of the dirt, but at least dig around a bit and maybe smell the dirt to see if you pick up the smell of any common chemicals, such as oil or gas.
      this comes from personal experience. my dad bought a property the city had used as a dump for road resurfacing w3aste and the dirt had a lot of chemicals in it from the old asphalt – he had the city pay for removing the top 3-4 feet of soil and put in fresh, clean soil.

      • nataku8_e30 says:

        @BrazDane: Along those lines, you also want to avoid watering your garden with rain water that came off your roof (for example, if you use a gutter / rainwater storage system). Many roofs leech chemicals into that water which you don’t want your food to absorb.

        @magic8ball: You actually could grow peanuts and then grind them yourself – nice, natural organic peanut butter and you can make a little bit at a time so you don’t have to worry about the oil separation issues you normally have. I remember growing peanut plants as a kid, they came in a kit with yarn to plant it in to get it started. There definitely are products you won’t be able to replace, but I seem to remember a tomato / jalapeno scare over the summer that could be avoided pretty easily with fresh vegetables. This solution isn’t for everyone, particularly people who are lazy and / or wise-asses. It’s also a bit more effective in the southern climate where you have a longer growing season and you have less need of canning.

        • trujunglist says:


          I live in an apartment and have had some success with growing my own tomatoes, peppers, and other smaller veggies and herbs that are suitable for containers. I had a serrano pepper plant that yielded about 50 peppers total. Not bad for a tiny pot! The herbs were the most helpful though by far; no more paying for fresh basil! I highly recommend a small container garden for everyone, at least for herbs, they really make boring meals a little less boring. I even add extra stuff to packaged food to give it some extra flavor. I did have a small balcony to put the containers on and I live in a great climate, but I know that many herbs are good as window plants, so try it sometime.

      • Jubilance22 says:

        @BrazDane: Very good point.

        I work for a large company & I heard lots of stories about the stuff we used to dump outside in the back. Now of course we’ve sold that land off to unsuspecting developers, who are then selling it off to unsuspecting families. And then of course, there’s the subdivision in Orlando where folks are finding old Army munitions buried in their backyards.

        Always check out your dirt folks.

    • Mistrez_Mish says:

      @nataku83: I hear you on growing at least some of your own food. I rent an apt, so it might not be glamorous, but I love my little window sil garden. I grow herbs, wee tomatoes, mini grapes, and mushrooms (no, not that kind…. shiitake and those little guys are in the kitchen… don’t take kindly to a lot of direct sunlight).

  6. talonscar says:

    If this was china, the owner/operators would be sentenced to death. Not a bad idea.

  7. lemonchar says:

    I wish more people knew about this stuff/cared at all. If I’m about to throw away a dented can of soup, my roommates tell me “it’s not going to kill you,” but what about going to the hospital? What about being sick for a week?

    I guess Americans are less concerned with diarrhea and cancer and premature puberty (thanks, growth hormones!) and more concerned with cheap, easy, tasty food products. So it’s a win-win with manufacturers. Nice.

  8. valarmorghulis says:

    Upton Sinclair eat your heart out.

  9. Burgandy says:

    This is my new diet, this post. Looks like no eating until the garden says I can.

  10. ColoradoShark says:

    This is just like all publicly traded companies picking and paying for their own auditors. If the auditing company doesn’t OK the books or charges too much, a new auditing company is brought in.

    Wasn’t there some airline company that got the FAA to remove an inspector they didn’t like?

    Companies should not be picking who inspects them.

  11. whitecat says:

    Peanuts are easy to grow, I hear.

  12. Trai_Dep says:

    If there was a law mandating that labs had to publish ALL their results (and that mfrs had to pay up before getting the results), wouldn’t that reduce the lab-shopping? Seems like it’d be a relatively easy law to write and administer…

    • ExtraCelestial says:

      @Trai_Dep: I think another post was pointing out that they didn’t force results to be published so that they would actually do the tests? I don’t know. I used to work in biotech and NONE of this kind of stuff ever occured. At least our meds are safe!!

  13. Odiase says:

    In a world were we spend 8-10 hours working. Almost 2 hours commuting, and several hours dealing with the stress of everyday life who has the time to manage a garden and make foods like bread from scratch?

  14. spittingangels says:


    The FDA has already reported that the Peanut Corporation of America found Salmonella in their product through testing, retested and shipped anyway. So I think we can safely imply their wrongdoing.

    Of course, with the protections given to corporations in the US, they’ll likely get a paltry fine and that will be the end of it. Someone needs to go on trial for murder here.

    This is a section of government that needs serious reform as the FDA has no true power over the businesses it’s supposed to regulate.

    • yasth says:

      @spittingangels: Eh with that finding the company is pretty much toast. The FDA may/may not get them, but the civil suits will destroy them. Lab shopping makes them insanely culpable for the illness and the death. Not only that but their suppliers will bill them for the loss which is likely to be massive.

  15. redskull says:

    @lemonchar: I used to work in a grocery store, and one time a lady asked me if we had any non-dented cans of corn in the back. I assumed she was freaked out about the dented cans because of potential botulism, but no… she claimed that there was less food in a dented can, and wanted to make sure she got her money’s worth.

    I guess she thought when a can got dented that half the ingredients squirted out somewhere?

  16. tator says:

    Buy less processed food. Grinding peanuts into butter doesn’t require secret recipes or exotic equipment. The more fresh local food, the less risk of contamination and the addition of who knows what. I use the local farmers market several times per week.

  17. Sunflower1970 says:

    The little confidence I had left in regards to food manufacturers has now been depleted to close to zero. Luckily, I began changing my diet a few years ago to remove as much processed food as possible and make as much as I can from scratch.


  18. Deleriumb32 says:

    Eww. I worked at the U.S.D.A. testing meat and poultry for salmonella and e. coli. It is exactly for the reasons above that the U.S.D.A. requires the government to conduct independent tests of the products. We also tested meat samples to ensure that they were labeled properly. Most frequently, beef contained beef and chicken contained chicken. There were times, though, that the beef in beef stew was really venison, or that the “fish” in “fish balls” from China was actually beef (which is illegal due to mad cow). Although government regulation is often abhorred, I think the way to prevent these outbreaks is to greatly increase funding in order to enforce the safe food standards that are already in place.

  19. Applekid ┬──┬ ノ( ゜-゜ノ) says:

    Wow, FDA requirements expressly forbid this one:

    2) Combining Failing Batches with Passing Batches

    Instead of posting here, microguy, be a whistleblower and usher in a new age with The Jungle 2: The Sequel

    • CrazyRedd says:

      @Applekid: Can we call it ‘Return to the Jungle” and subsequent food contamination/safety practice exposes called “J3: Call of the Wild” or like “Son of The Jungle”?

  20. HarcourtArmstrong says:

    When I worked in the automotive world, our quality auditors would have to be mutually agreed upon by us and our suppliers. Our suppliers then paid half of the cost of the audit. This was to ensure these kinds of shenanigans didn’t happen.

  21. LabanDenter says:

    “We Fail All Lab”

    Thats the kind of lab people around here seem to want.

    Why dont we have companies shop around until they find a sample that fail.

  22. Eryn DeLille Cobb says:

    That is frightening, and I easily believe it is all true.

    I do have a question though:

    How do you avoid the risk of contaminated products? With all of the recent contamination, is eating anything safe? Are we just playing “Russian Roulette” every time we eat a salad or a peanut butter sandwich?

    Is the answer to go organic? Are organic products any safer?

    • Joanne Rigutto says:

      @Eryn DeLille Cobb:

      I think the thing is not so much can you completely avoid contamination, although that always needs to be the goal.

      The problems I see with the industrial food system as it is now is the fact that in so many instances you have lots of raw material from many sources that are being funneled into a very small number of processors, and often what that processor producess goes into many other products, some of which will continue on to still other products before the finished product hits the store shelves.

      That kind of production produces bottlenecks which can not only cause lots of people to be sickened all over the country, but can cause one farm in a thousand to contaminate a whole season’s production. It also means that one plant processing everything, can contaminate a lot of product if the contamination happens at the plant.

      That’s the advantage of small locally sourced ag. If someone gets sick from the tomatoes produced on my farm, I’ll effect people within 20 miles of my home. If I ship contaminated tomatoes to a big processor, I can make people all over the country sick. Which is why I don’t intend for my farm to get too big. Besides, there’s more proffit in selling locally.

  23. savdavid says:

    Anyone against government testing and consumer protection ought to think long and hard about this. Remember, there is NO such this as a free market as companies work to protect profits, not people. There is also laws written by lobbies for the Congress to pass to protect their industries (after they pay off the politicians, of course)

  24. microguy07828 says:

    I posted a few comments to another article few days ago, but I would like to re-post them here. Below describes some of my experiences with manufacturers when dealing with GMP violations/potential microbiological contamination issues in manufacturing plants.

    It has been my experience that many companies do not take potential microbiological contamination issues seriously. It mostly has to do with the fact that microbiological organisms are not visible to the naked eye. After all, it’s hard to convince someone that a problem exists if they can’t physically see it. You’ll have a much easier time getting a crooked label issue fixed right away (something they can see), than getting cleaning and sanitization issues addressed (something they cannot see the consequences of at that moment).

    The goal in any manufacturing plant is to get the product out of the door, so that the company can get paid by its customer. A microbiologist (or trained microbiology representative) that raises Good Manufacturing Practice (GMP) issues is often thought of as an individual who is “throwing a wrench in the works”, slowing production. It’s often difficult to get management to take GMP issues seriously, especially if the plant has not had costly microbiological issues before. After all, everything was running just fine until the microbiologist showed up.

    Don’t get me wrong, there are a lot of great companies out there who are working hard to produce a quality product, but from my experience, many companies do not take GMP violations or potential microbiological issues seriously until it affects the bottom line. Unfortunately, by the time some companies decide to take GMPs seriously, it’s too late.

  25. sonneillon says:

    Also when inspectors come it is not uncommon to repack newer material in older lots to make sure that those lots pass inspection then use the older stuff.

  26. Phexerian says:

    #2 is quite well known in the peanut world. When peanut farmers test their batches for aflatoxin B1 and find high amounts of it, they don’t throw away their batch. Instead the mix it with another batch that was tested with low amounts and thus both batches are now below the legal requirement. They have been doing this for years. The FDA knows it as well but doesn’t seem to care.


    This site gives a little more information.

    -3rd Year PharmD/MBA Candidate

  27. OneQuietDave says:

    Ask anyone in the processed food industry if they eat the food that they produce. Most have experiences that put them off their company’s products forever.

  28. zimmi88 says:

    I like to think of myself as an optimist… thinking that humanity is, all in all, good.

    Then I read articles like this. And my faith in humanity dies a little.

  29. ceez says:


    yeap,the world of fast, high paying cold hard cash is going to bring humanity to its knees!

    tainted toys, bad, but children can live without

    tainted food, really really bad, cant live without food.

    grow your own….that bag of dirt….how safe is it? is your land infected already? using pots? are the pots tainted?!?!

    oh we’re all so doomed.

    thank you greedy world!

  30. TrueBlue63 says:

    Read The Jungle by Upton Sinclair, you don’t need to read the whole book, but the parts about meat processing will inform on what food processing was like around 1900.

    Laws were passed to correct much of this, but its been 100 years, they manufacturers have a whole new bunch of tricks up their sleeves.

    Whenever possible, Buy Local, Buy Small, make your own, and remember eat in season.

  31. synergy says:

    Having worked briefly (3 months) in a food safety lab, I agree from what I saw back then (over 7 yrs ago) that these things are very possible.