There is no safety issue with adding cold milk foam to hot coffee. Coffee aficionados recommend against adding cold mild to hot coffee, because they suggest it compromises the flavor of freshly brewed coffee. Their recommendation is that any milk, foam or not, should be warmed...but it is not a food safety issue.

There is no safety issue with adding cold milk foam to hot coffee. Coffee aficionados recommend against adding cold milk to hot coffee, because they suggest it compromises the flavor of freshly brewed coffee. Their recommendation is that any milk, foam or not, should be warmed, but it is not a food safety issue.