Baking soda is the usual method to prevent odor but it may take a while to eliminate odor. Try also vanilla extract in a flat dish and just wadded up newspapers.

maybe it’s time to clean out your fridge? i would empty it out, and wash shelves and all, inside and out with warm water and vinegar, or even a mild solution of bleach and water. you may have spilled some milk, or something maybe growing in the back corner. i usually do this atlest 4 times a year.