It depends what kind of shortage we are talking about.
Fruits, meat, rice, pasta, locally produced products, washing powder (Ala, etc.), water, etc. won't be affected by shortages in my opinion.
More specific products (talking just about the French ones: Bonduelle vegetables, Maille mustard, Roquefort, Camembert Président, etc.) could indeed be affected.
Really? I've noticed over the time I've been here that the imported products seem to be significantly less affected by inflation than locally produced products; I would assume that would mean more normal reordering in a price controlled environment.
For example Grey Poupon dijon mustard (okay okay, "dijon style" ) has gone from about 23 pesos to 28 pesos on the shelves of my local coto in 3 years where as I've seen quilmes go from 3.70 to almost 9 in the same period.