In the area we live, there are a big number of ants. They are almost everywhere. The food is mainly affected and they enter inside the bread. Thus, there is a chance every time during eating bread to have multiple ants eaten.
If the ants got into the bread before it was baked, the ants have simply become a little addition to the protein content of the bread. If they get in the bread after it has been baked, the answer is the same. The amount of formic acid - or other - toxin - are in vanishingly small concentrations. I wouldn't worry at all.
Where I live, in the southwestern US, certain ants have been a part of the diet since ancient times. Some kinds are roasted before eating them. Others are eaten fresh. They are quite tasty!
Consuming ants ,regardless of the amount, is not harmful at all. We should be very worry about what ants can transmitted e.g.all kind of PATHOGENS. I never forget that, in the US, ants were identified/incriminated in transfer the serious pathogen (Listeria monocytogenese) to cheese kept , during maturation period, in a refrigerator in cheese factory. B.Regards Sayed .