kosher cheese

Question

Hello, I follow your psak with regard to cheese, i have clarified with you at least with american cheese the ingredients even in hard cheese are kosher, but the gzeirah against gvinat akum (gentile cheese)in the gemara is still valid and it forbids us from eating cheese manufactured by gentiles, no matter how kosher the ingredients. I am interested to know exactly where in the gemara it says this , and what specifically it says. I agree with you, that one doesnt ask around once social circle if things are kosher, treif assur mutar, we follow the halachah. so i am curious where is it written what does it say...we be useful in arguments. thank you again for establishing sanity in hilchot kashrut