How long is it okay to marinate pork ribs for? I want to grill pork ribs for lunch on Sunday and usually I marinate them in the fridge over night (&lt;18 hours). The supermarket only had &quot;fresh&quot; ones (usually I buy pre-packaged, which are good for a couple of days), so I asked if it was okay to keep them in the fridge until I marinate them tomorrow and the guy said:

Yes, better even marinate them today to add more flavor!

I've never heard/seen anyone marinate meat for more than maybe 18 hours, let alone almost 2 days. Is that really an okay thing to do?
The marinade is: 3Tbsp ketchup, 2Tbsp apple juice, 1.5Tbsp balsamic vinegar, 1Tbsp honey, 1Tbsp BBQ sauce, 1.5tsp soy sauce, 1.5tsp mustard, 1.5tsp sugar, 1 onion and a couple of ground spices.
If it's not okay to marinate the ribs for that long, is it still okay to keep them in the bag in the fridge until tomorrow evening or should I rather freeze them now, then defrost them again in the afternoon tomorrow?
This is totally okay to do and will help flavour your ribs deeply. 48 hours is the max I would marinate for personally. If you're really skeptical about it, you should be fine to keep your unmarinated ribs in the fridge until you're ready to marinate them.