i think it might have been the expired mustard - i opened it up, and found it clumpy, and discoloured. like, green. the teaspoon i squeezed out looked ok, but the due date was august, 2019. so, all evidence suggests this condiment was badly degraded. i've unfortunately decided to discard it.

i used to eat salami cheese melts fairly frequently, and the mustard just got forgotten about when i moved past it.

i will get mustard powder next time, instead.