It is not bacteria on the probe but bacteria on the surface of the meat that is being pushed into the meat. Read through the BBQ forums and you we see reference to it.
I prefer to look at science resources for information regarding risks of cooking and methods and avoid repeating what people believe is "common knowledge" touted on forums re: health and science issues. That being said, i'm going to post some science links about that subject ON THESE FORUMS!
What i know of microbiology and innoculation of media provides me with a fairly high certainty that this is not a problem. If anyone got sick from such an occurrence, it is likely more probable causes were not ruled out.
For example, one has to assume that surface bacteria is in sufficient quantity such that a pen tip sized probe can 'push' enough into the centre of the meat such that a person will ingest a quantity sufficient to cause sickness. Animals are capable of withstanding the ingestion of various amounts of bacteria before it makes one feel sick.
Second, the surface of the meat cooks faster than the inside, so killing of surface bacteria has already begun by the time anyone would put a probe into the meat.
Third, what "surface" bacteria are we talking about?
The bacteria most common to beef and chicken are found INSIDE the meat, not just on the surface. Hence, unless someone left their meat out on a counter for two days and something else started to grow, then these poisonings have zero to do with a probe insertion. If something else did grow, then that has little to do with the probe vs. poor food handling.
There are three primary reasons why meat products are cooked to certain temps. Knowing how/why these contaminants become factors in human health will provide any food preparer the knowledge that they need to prepare food safely.
Chicken - Salmonella (all types)
Beef - E.coli (only for processed products)
Pork - Trichinosis
Resources for why people get sick from these factors can be found anywhere, but many myths abound. The bbq forums are NOT good places to confirm facts. I won't go through all three, but can at least focus on pork as one example.
The very reason why people have long been told to cook pork thoroughly have been alleviated with scientific study yet many people still follow the 'old' "common knowledge" to cook pork past pink, min. 160F, etc. (Note that the 160F standard is still the guideline in Canada but the US has lowered theirs as of a few years ago).
Trichinosis are killed in less than 1 min at 140F, and are killed under freezing temperatures (USDA fact sheet).
http://www.aphis.usda.gov/vs/trichinae/docs/fact_sheet.htmSimilar info is posted at the CDC site with more on wild game meats.
http://www.cdc.gov/parasites/trichinellosis/prevent.htmlAs such, any pork you had frozen for a day before eating, you don't have to worry about eating pink and contracting Trichinosis worms. Still, the cooking guideline says to cook to 140F. Using those TWO combined methods, along with the usual "keep your hands and prep surfaces clean", pretty much eliminates any chance of problems with pork unless the meat was bad to begin with. If the pork was left out for bacteria to grow, then even after freezing and cooking, bacterial toxins...Staphylococcus aureus produces a heat stable toxins may be left behind. It wouldn't matter if Staphylococcus only grew on the surface or got pushed into the meat with a probe. That has zero to do with the fact that the heat stable toxin being left behind on any part of the meat is the cause of the sickness. The primary cause is poor food handling and prep.
If i were to guess, i would think unwashed hands is likely one of the largest reasons how people contaminate their home meat during prep.
Here is an article from the CDC about stats on foodborne illnesses from 2011. Note how they actually recommend using a probe in meat to check temperatures.
http://www.cdc.gov/Features/dsFoodborneEstimates/
