My wife's post about weird science reminded me of two different experiences I had with roommates at two school. My first quarter in college, I moved into a dorm room with a buddy I had met the year before at a summer program. We shared a mini-fridge since the hall fridge was just a good place to have food stolen. The school required that all appliances by unplugged when students were away for break, so we had to unplug the fridge. I finished finals before my roommate, so I told him just before leaving, "Hey, I know you still have food in there, so just clean it out and throw anything away, then unplug it when you go."
Somehow only that last phrase "unplug it when you go" was the only part he listened to. I came in to start the new term, plugged the fridge back in and opened it to put in a soda or something. If green smoke had come out to color the smell that hit me, I would not have been shocked. I nearly vomited right then and there, and I almost fell over. I quickly closed it back up and went into the hall to catch my breath. If I had known when my roommate would be back, I might've saved it for him to find, too, but instead I cleaned it out. That was the first time I learned that mold could be orange and yellow (on top of white and green). It was also the first time I learned that butter could grow mold.
A year and a half later, I was sharing an apartment with three other guys. Todd and I chose to use my mini-fridge and let the other two guys use the main fridge. Because of a strange set of circumstances, Todd and I ended up having the apartment to ourselves for more than a month. Because of that, we decided to finally use the main fridge, which had ignored by the vacating roommates.
What we found was pretty disgusting. In the vegetable keeper, there were blobs of things no longer distinguishable as a particular fruit or vegetable... or as food, really. Then there were the various bottled substances. I say substances because they had expiration dates from our senior year in high school, nearly three years before and a year before Todd had moved in (I joined him a year later). I'm pretty sure that means they were no longer "food" or "condiments".
I am amazed I did not die of food poisoning or some random fungal infection thanks to those two experiences. I did have a lot of breathing problems in college, which probably were not helped by the disgusting filth my roommates kept in the kitchen. So when I opened the "rice" my wife had left, at least I had dealt with such things before. Hers was mild by comparison.