The translators need to correct this. This is Beta and I guess that is to be expected.
We always wrote "Холодільник" with an "i' and not an "и".
Explanation: "Холод діляє" not "холод дилає". There's a reason behind the spelling & meaning of a word. Let's use them properly! :D
Actually, холоди́льник 'refrigerator' is related to холоди́льний 'cooling, freezing', which in turn is formed from холоди́ти 'to cool, to refrigerate, to freeze'.
Professional refrigerators (as opposed to ones for home use) can be named холоди́льна ша́фа, literally 'refrigerating cupboard'. Some places can even have a complete холоди́льна ка́мера 'refrigerating chamber', a room with low temperature.
Холоді́льник seems to be either a secondary change based on folk etymology, or a borrowing from Russian (which has холоди́льник, pronounced халаді́льнік). Anyway, холоді́льник is not used in literary Ukrainian, and therefore it's not accepted in this course.
By the way, «діляти» is also not used in literary Ukrainian. What does this word mean? Is it a variant of «діли́ти» 'to divide, to separate'? If so, then what exactly does refrigerator separate? It makes more sense to form 'regrigerator' from the adjective 'refrigerating', and from the word combination 'the cold divides', isn't it?
Is 'холодильнику' indeed Loc as Duo suggests as a hint? The inflection '-у' looks like DAT to me and, moreover, the dative case in Slavic can perform inessive functions, which btw is the case in this sentence. In contrast, what I usually associate with LOC would be something like 'холодильницi'. Has this "form" (ending in '-i' for m. gender) been lost universally or simply this is atypical example that employs dative /rather than "true locative"/ to indicate location?
Dative and Locative basically overlap in their form. It's a bit redundant. But it's easy to decide: if you see "on", "in", "at", "under" etc, use Locative, Locative has the same form as Dative (can't think of any time when it doesn't, anyway it's worth a bet), so just use Dative :D
"Food is in the fridge" sounds a little awkward.
Maybe it would be better like this:
The food is in the fridge.
There is food in the fridge
Some food is in the fridge.
I agree. Changed the default to "the food". "Food" is still accepted since I think it's grammatically correct, but yes, awkward.
In this case it's Locative, it just coincides with Dative (I can't remember any form that doesn't, actually, pretty redundant). Locative is for "in", "on", "at", "under" etc, location-related.