My bad! A customer got sick eating our food, and the following is information we need to collect to investigate

Pretty sure food eaten elsewhere doesn’t matter to you. Also if they waited to eat the food is important, because if you gave them something that expired that day and they waited til tomorrow, that’s important. Cutlery doesn’t matter, where they work doesn’t matter. If public health notices a pattern with your workplace then they’d investigate, so you don’t need to collect info on where the person works, what else they ate at other places, what cutlery they used. Just their contact info, what they ate at your place, when they ate it, when you sold them the food, when they felt sick, did they see a doctor, and did the doctor contact public health