In German "im Abverkauf" (common expression) means that goods are being offered at a reduced price.

Here are some other examples to ease comprehension:
Ich habe mir diese Schuhe ganz günstig im Abverkauf gekauft.
Bei *Firma XY* gibt es tolle Fernsehgeräte im Abverkauf.

Your suggestion "intended for sale" is ok but it does not clearly express whether the cakes are intended for sale at regular price(Verkauf) or at lower price (Abverkauf). And it's important to stress that the goods are sold at lower prices which also explains why they can be kept for a short period of time at a temperature that is not suited for long term storage.

My suggestion would therefore be something like "for cakes on sale" which means in Am. Engl. that they are offered at a lower price.

(Reference: Native speaker living in Austria, Oxf. Adv. Learn. Dict.)

I hope this helps you.

Warm regards
Claudia