I do the occasional food shot for a client of mine and the focal length I use the most is the 50mm macro (the FA 50mm f/2.8 macro and the DFA 50mm f/2.8 macro). I do use a longer macro but less so due to the narrow angle of view and working distance issue. I'm sure the DA 35 macro can work as well but at larger magnifications, the working distance can be a little too close especially when strobes are used.
The determining factor is whether the shot is to isolate the subject or to have the subject shown in relationship to a particular setting. For the most part, the requirement is for a lens with a wide enough coverage that gives a good working distance.
The reason why a 50mm macro and not a normal 50mm is because of the close focus capability and because macro lenses are flat field corrected so objects shot up close don't get distorted. For commercial shoots, a tilt shift lens might be used to tweak the plane of focus.
Some test samples:
FA 50mm macro
Sigma 90mm macro