possible sperm in my pizza at a store

Throwaway account for this...

About 2 months ago, I ordered a pizza, which arrived late by more than 35mins past the expected delivery time and didn't have chicken when I requested double chicken. At the door, I had a huge argument with the delivery guy and I spoke to the store manager and threatened not to buy from them again and they ended up saying "keep this pizza. We will not charge you anything" and I did, but I've never ordered by phone again to that address for fear of what I think may have happened today. Fast forward a few weeks, I went to the store which is just around from my work and I ordered a pizza and had it inside the store. As I'm about to leave the store, the driver I had the argument with is about to come in and he looks at me, recognizes me and puts sort of an evil grin and continues walking. So today I went there again and ordered the usual pizza and I a slice and underneath the tomato there is this gooey substance all over the base of the pizza. The taste is not clear, but the texture that stays in the mouth is very very similar to sperm (Don't ask.)

Now, I don't know if I am being overly paranoid, but the pizzas I order are always very simple (I never change): no cheese, onion, pineapple and double-chicken and I can tell the taste and texture today could very easily be misguided by cum. I've kept the remaining slices of the pizza and I'm sort of curious to know if there is anything I can do to confirm if there was any substance in my pizza that shouldn't be there and if so how/where. In fairness, the situation is a bit complicated as I don't want to speak to anyone of my family/friends that I may have tasted someone else's sperm, as it'd be awkward to explain how I know the texture. I also don't know what type of laboratory would be able to assist me in finding out if my fears are right (if this is possible at all).

In other words, if I were to search for a lab to have the leftover pizza tested for sperm, what type of lab and price would I expect to be charged for this?

BTW, I'm based in Dublin, Ireland. I may end up revealing the pizza store name/address, but I'd rather leave that out for now as it's just me acting the paranoid.