All my doctors have told me to avoid mayo.

The thing to remember with listeria is that it can rear it's ugly head up til 70 days (info from the info at the midwife clinic at my hospital) after you've eaten something contaminated with it and often you don't get symptoms so you wont know you have it until it causes a problem with bubs.

I say avoid it til the birth. Having had 3 unexplained losses already I'm not taking any risks.