Question: A coffee shop has a coffee machine which is only used in conjunction with coffee beans and water. The milk is placed in an external metal jug and this jug is put under a pipe which blows hot air into the milk causing it to heat up and froth. The metal milk jug and hot air pipe are cleaned between each customer.
If one asks for chalav yisroel milk (which is an option), is it permitted for the milk to be heated up/frothed in the same utensil used for non cholov-yisroel milk? (The milk appears to reach a temperature of yad soledes bo.)
Answer: It appears to be problematic to drink (coffee containing) milk that was frothed/heated up with a pipe that was previously used in conjunction with cholov akum, because the cholov yisroel milk now contains bliyos of cholov akum, and presumably it is within 24 hours of the cholov akum usage (ben yomo).