I have just made some cheese sauce and have used some Gruyere in it. I've just noticed on the label that it is made with raw milk, so unsuitable for pg women, those with low immune system etc. is this ok for my 9 month old ds? I am aware that he can't have Stilton type cheeses until over 1, but what about Gruyere?
listeria is sensitive to heat, so in making a cooked sauce any listeria will be killed.
In a fully healthy baby I personally wouldn't worry about giving it or stilton uncooked to a baby younger than 1, Listeria is really only particularly serious in pregnant women (where it can cause miscarriage) and those with weakened immune systems, a healthy 9 month old doesn't come under that heading for me. It's rare in any case.