To be totally honest I have no idea, they come 12 to a box and they last about 2 weeks.
Since I feed a whole one a day.

if you keep them in the fridge they will be some what dormant and won't eat much.
I keep mine in the door at the highest level so that is the warmest place in the fridge.
I have noticed that the "earth" gets dry so I just add a teaspoon of filtered water room temp
to the earth in the box.

and I haven't had had any die.

And if your family is totally against you putting worms in the fridge then a small dorm room fridge will do nicely. Just set it to no colder than 39-42F or you might have worm sickles LOL