Mouse in a Can

Case Description

These are real cases, but they sound like an urban legend. Somebody buys a canned drink or packaged food. They go to their car or home, open the product, consume part of it, then get a nasty surprise. Maybe it was a mouse in a beverage can. Maybe it was a bit of plastic or metal in a food product. Either way, a foreign object has somehow found a way into a packaged food product, and everybody wants to know: How did it get there?   Cases like this tend to capture the public imagination, and they also have historic importance. One of the most important cases in modern product liability is 1932 Donahue v Stevenson, or the “Paisley Snail”, where a woman in Paisley, Scotland claimed to have fallen ill after consuming a bottle of ginger beer that contained a snail.  

Steps Taken

Every foreign object in food case is unique, and ARCCA experts tailor their approach to the claims made in the case and the evidence available. Depending on the information and evidence available, the expert has different strategies they can employ:
  • A forensic analysis where the expert examines the foreign object, food product, and packaging to find evidence of their history.
  • An engineering analysis where the expert assesses the manufacturer’s facilities and production processes in order to determine if and how a foreign objection would be able to get into the product.
  • A scientific analysis where the expert designs experiments based on the specific claims in the case and determine whether the available evidence is consistent with the claims.
The forensic, engineering, and scientific approaches all have advantages in different situations. However, the forensic approach requires access to well-preserved evidence (often not available in food cases) and the engineering analysis can be difficult to tailor to address the specific claims made in the case. The scientific approach is typically the best choice, because it addresses specific questions in the can and can still work with limited information provided by a claimant. For example, ARCCA has investigated several claims involving rodents found inside of beverage cans. For these cases, the ARCCA expert used the claims to develop a hypothesis to test:
  • A rodent was somehow introduced during the canning process.
  • The rodent and beverage were sealed in the can for a certain amount of time.
  • The claimant found the rodent inside the can, took photos, and used the photos to support a claim.
In some recent cases that went viral on social media, expert or amateur investigators would put a mouse carcass into a container with some beverage, wait for a while, and note that the mouse would deteriorate dramatically. This led to headlines like “Mountain Dew Melts Mice” or “Pepsi Says Mountain Dew Can Dissolve a Mouse Carcass”. However, those experiments did not actually match the claims made, and the headlines reflect a misunderstanding of what would actually happen to a mouse if it somehow found its way into a can. The real question, in these cases, was not whether the Mountain Dew would dissolve a mouse. The question, based on the fact that the mouse carcass was in excellent condition, should have been: “Does Mountain Dew preserve the mouse and prevent it from decomposing or changing?” The experiments demonstrated that the Mountain Dew is a poor preservative for dead mice. Additionally, the experiment should not have been to simply dump a mouse into some Mountain Dew – because that did not actually match the claim. The claim was that the mouse got into the can during the canning process, and industrial canning processes involve much more than just filling and sealing cans. In ARCCA’s past cases, the ARCCA expert replicated the industrial packaging process for the product and foreign object involved the claim. Depending on the case, this would involve steps like pasteurizing a beverage, carbonation, filling the can or package, purging with nitrogen, seaming the can, cooling the sealed can at a certain rate, then storage and distribution of the finished product. Each step of the packaging process could have an effect on a foreign object. By designing and executing an experiment, the ARCCA expert learned about those effects and compared them to the object involved in the claim.

Materials and Biochemistry

Collagen Chain ARCCA experts have documented a wide variety of biological, chemical, and mechanical changes in rodent carcasses subjected to an industrial canning process. One of the most important changes is denaturation of collagen. Collagen is a protein, and it is the material that gives most mammalian tissue its strength and resilience. Collagen forms strong fibers, which are a crucial component of skin, bone, tendons, ligaments, cartilage, etc. However, under certain conditions collagen loses its structure and breaks down, or denatures, which transforms the strong collagen fibers into soft, mushy gelatin. This denaturation process is familiar to most people because it is part of many cooking techniques. Slow-cooking and sous vide cooking tenderize meat by denaturing collagen using heat. Ceviche “cooks” raw seafood by denaturing collagen chemically with citric acid.  

Final Findings

  ARCCA experts have found that heat from pasteurization tends to denature the collagen in any rodents that are added during the canning process. Depending on the product involved, citric acid (citrus), carbonic acid (carbonation), acetic acid (vinegar), or other compounds could also have chemical denaturation effects. During the canning process, the rodent’s body usually becomes extremely delicate and falls apart unless the can is handled gently. Using this information, alongside other physical and chemical changes found in experiments, the ARCCA experts were able to determine whether or not the rodents from claims could plausibly have entered the can during the canning process, or if they entered the can after the it had already been opened by the consumer.
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