OK Guy's you are all right! Under certain circumstances...
The Black and White...
The probe will push some bacteria in.
Typically, 4 hours in the danger zone and that bacteria grew.
Cooking to 165° or 140° for 12-15 minutes would have eliminated that bacteria.
Yes some common bacteria produce toxin. Many of those toxins are destroyed or inactivated at 200°F.
Cutting away the meat about a 1/2" around the area the probe was in will remove any nasty stuff.
Sterilizing the probe removes bacteria...ON THE PROBE...It has zero affect on the bacteria at the probe site. So while a good idea, MUST be combined with eliminating the bacteria on the meat. This will happen by waiting an hour or so for the meat surface to heat before adding the probe or heating the entry point with another source like a torch or even touching the area with a very hot piece of metal, think, Branding the meat.
Now the GRAY that must be considered before throwing that expensive meat out...
Was the work surface, probe and hands clean before work began? Goes a long way toward safety. Note: Clean DRY probes are bacteria free.
Was the meat washed, carefully, no splashing other surfaces before probing? Was a Salty rub applied and allowed to be in contact 15 minutes or longer? Both of these greatly reduce or eliminate bacteria.
Does the bacteria suddenly produce huge numbers and high levels of toxin at exactly the 4 Hour mark? No, some can reach high numbers in 1 hour at 90 to 120°F, others can take more than 6-7 hours to reach any serious levels.
4 hours is NOT a magic" toss the meat number " The FDA uses 4 to 6 hours as a guideline.
Will the temps we cook brisket to have killed the bacteria making it safe. Yes. The only concern is proper cooling, storage and reheating of leftovers.
Will the amount of toxin that may have been produced have killed you? Not necessarily. Of the many types of toxin only a few are deadly. Others only are a danger to the very old, very young and those with immune system issues.
If the typical storage and clean handling techniques were used, the meat was washed and/or at least had S & P or a Rub on it, as I suspect it was and was cooked to typical Brisket temps, EVEN with the 6.5 in the danger zone, and the Probe being the only thing the broke the surface...It was extremely likely that Brisket was perfectly safe and delicious. I would have served it to my family...JJ