A family we were friendly with growing up had the following happen: The mother got sick and ended up in the hospital. She was diagnosed and treated, and while explaining the illness, it came up that this particular illness come from pork. So of course she asked, well what else can it come from? The doctor said maybe if you visited a certain country. So she says, there’s got to be another way, I have never visited that country and I’ve never eaten pork. The doctor says well maybe you unknowingly ate pork. The family did a little digging and found that their housekeeper, who they also allowed to cook their meals, would often eat her pork enchilada for lunch and then handle food preparation for the family. Scary, from both a kashrus and a hygenic perspective…
That being said, there’s only so much you can do. You need only follow halacha meticulously. Chumras are ok too but you can rely on them from today until tomorrow, and there will still be a way for mishaps to happen. Do your part, but no need to drive yourself crazy with hypotheticals. Daven that Hashem should protect you from inadvertently eating non-kosher food.