I don’t think the any antibiotics are intentionally put into processed food in the US. Residual antibiotics may be found in meat, because they were fed as growth enhancers to the animals. Some people are allergic to Penicillin, so one would think there would need to be warnings if it was being introduced into the food supply.
I’m going to take a stab here and say that you are confusing antimicrobials with antibiotics. Foods often have antimicrobials in them to give them longer shelf life. Some examples of antimicrobials found in food are Sodium Bisulfite, Sodium Nitrite, Sodium Nitrate, Calcium Propionate and Disodium EDTA.