Help needed. Any tips to get rid of this ghastly smell.

In a similar situation with smells in a fridge, we do the following. Slice two lemons in half, remove some of the flesh from each half and then fill each of them with bicarbonate of soda. Place these in your case in the cupboard so they are sitting upright, you may need to sit each of them in a cup, and shut the door. Usually within a couple of days the smell will have gone and be replaced by a light lemon fragrance. If after two days the smell hasn't completely gone but is starting to fade then just repeat the process again with fresh lemons and bicarbonate of soda.

i would try baking soda.sprinkling it directly on the shelf if i had to. but that usually absorbs most foul smells.

As Scarlet woman said I would sprinkle the baking soda directly on the shelf. Baking soda and vinegar are my favorite cleaning products. I use baking soda as a carpet deodorizer and to scour sinks. Vinegar is great for sanitizing any thing. It will also kill weeds. put some baking soda down drains followed by vinegar will clean and freshen them. Baking soda is added to baked foods that have acidic ingredients and releases bubbles to cause the product to raise.

Wipe the shelf down with vinegar, or leave a bowl of it in the cupboard. Or put a little vanilla on a cotton ball and put in there. Scrub the shelf with baking soda, or put an open box there, or I have also heard of putting old coffee grounds in a dish to absorb odors.

Hmm.. Some good amount of Lysol should do the trick. But if it doesn't work, we put coals in our fridge to get rid of the smell. You could also try how carpenter's do it, they put a bowl of vinegar to get rid of the foul smell of paints, perhaps that could work.