K, I saw your profile - he is a little piggy pop!
As far as I am aware they will not be able to digest it..as long as the guineapig gets plenty of hay and fibre to flush it out there should be no big big issue as it was a small piece and it was once.. though keep your eye out on the piggies weight and be vigilant against BLOAT. He may get bloated. The meat may have an adverse effect on the gut fauna, but if he is in a cage with his cage mates and can eat his cage mates poop this will help keep his gut fauna topped up. Make sure for the next couple of days to remove his poops if you know they are his (impossible I know but I mean if you have him out for long play times and you see him passing poo). You dont want anyone accidentally re-ingesting the meaty morsels.
Take him straight to the vets if you see anything weird happening. They may be able to prescribe some gut stimulants to help flush his system.