milk
cheese
meat
fruits
vegetables
eggs
IT does not gets spoiled because, the air tin doesn't goes into the fridge and bacteria is killed.
Something that goes into something.
Don't know about a ready made device, but, it can be easily done. All you need is a relay, the coil of which is fed from the same power supply as the refrigerator outlet. Take a feed from a different circuit than that of the refrigerator outlet (eg a fed from a lighting circuit) and wire that through the Normally Open contact of the relay and then on to a simple sounder or alarm or electric bell etc, or even a warning light. An electrican could easily whip something like this up, i would think for minimal cost. Or if your keen u could do it yourself.Another answerJust Google "refrigerator alarm" and you should get some good results. Refrigerator alarms are available from as low as $9.99
Buttermilk typically lasts for about 2-3 weeks in the refrigerator before it goes bad.
Coleslaw typically lasts for about 3-5 days in the refrigerator before it goes bad.
Tuna can last in the refrigerator for up to 3-4 days before it goes bad.
A boiled egg can last for about one week in the refrigerator before it goes bad.
Butter can typically be kept in the refrigerator for up to one month before it goes bad.
Coleslaw can typically be kept in the refrigerator for 3-5 days before it goes bad.
Tuna can be kept in the refrigerator for up to 3-4 days before it goes bad.
Parmesan cheese can last for about 6 to 12 months in the refrigerator before it goes bad.
Brie cheese typically lasts for about 1-2 weeks in the refrigerator before it goes bad.