Alhumdulillah that is a good news that you got the job in the store where there is no alcohol that is the promise of Allah that who fears Him He open for him outlets and and grant him sustenance from the place he has not imagine.
There are three types of the gelatine
If it is veg(soya) it is allowed
If non veg it is not allowed if it is not written then you may consume it but still do precaution.
Pork is absolutely haram and selling of pork is haram too. Now your issue
If there is a stuff and in it gelatine then it is allowed but still ehtiyat is to refrain from selling it.