The media sure knows how to drum up a frenzy.
Not long after a World Health Organization report came out stating that red meats can contain carcinogens (as if that weren’t know already), Clear Food published a report of a study they performed on hot dogs. They found that “some” hot dogs contain human DNA.
Is their work correct? I don’t know.
How seriously should we take their report? I would say, “Not very.”
Clear Food analyzed 345 samples of sausages from 75 brands from 10 retailers. They found that a total of 6 of the samples contained human DNA. Cannibalism is a big deal, so it is important to ask what that means. How much of the hot dog is made from humans? Is it material like hair and dead skin cells (things we inadvertently eat all of the time)? How do we know that the hot dogs weren’t contaminated with human DNA during their testing? Furthermore, how accurate is their equipment? Does anything they identified as a positive match fall within the error range of their equipment?
Speaking of their equipment, what exactly did they use to perform the tests? What methods did they use? Has Clear Food published their exact procedures for their tests so that someone else can repeat it and get the same results? Testing is all about repeatability. If it’s not repeatable, then no conclusions can be drawn from it.
As I said before, they picked 345 samples from 75 brands. Was it 345 varieties or fewer varieties and multiple samples of each? Did they get enough samples to ensure that multiple batches of the same product were represented? Are 345 samples enough? Did they detect human DNA in a single sample and declare that brand and variety to have human DNA in it?
Interestingly, Clear Food has not published with hot dog brands contain human DNA. Why not? As a consumer advocacy group, wouldn’t their goal be to alert consumers of those bad companies? My suspicion is that they do not have enough evidence to prevent their study from being disproven.
My point is not that independent testing is bad. It is excellent and necessary. But the scientific method and proper statistical analysis cannot be ignored. If someone else repeats the testing with the same results, Clear Food gains credibility in my eyes.