You pull a jar of salsa out of the fridge. You don’t remember when you opened it up. A week ago, 2 months? maybe 3?
I used to run into this problem more than I liked. We’d throw out food because we couldn’t remember when we opened it. Having been a former Army cook and before then, an AP Bio student, I have food safety burned into my brain.
Jars, cans, pouches, vacuum packs, not to mention frozen items, they’ve got a long shelf life. But once opened, most foods have a much shorter lifespan, even with the wonders of refrigeration.
So I got the idea to write down the date when I opened up a jar (tub, resealable pouch, can, etc) before I stuck it in the fridge. I now make sure I keep a permanent marker or two in the kitchen. At first it was easy to forget to do, but after a few months it became second nature.
Until someone invents a device which automatically counts how long something has sat in your fridge, this is the simplest and most cost effective way I’ve found to track the venerability of your refrigerator denizens.
If you get into the habit of writing today’s date on it before putting it in the fridge, then you won’t have to play guessing games with the food that you put in the fridge. I don’t have any advice for your family and guests, except locking your fridge or going through even more unsociable extremes.