Low-res digicams (under 20 megapixel) are pretty marginal for serious food shoots; 15-20 years ago, when I was shooting quite a lot of food professionally, even 6x7cm met with a lot of resistance and 4x5 inch was preferred. On 6x7cm I normally used 135mm; on 4x5 inch, 210mm (rough equivalents in Leica terms 65mm on full-frame, 50mm on M8).
His dictis, for web illustration I tend to use a D70 + 90/2.5 Vivitar Series 1 Macro. If I wanted to use the M8 I'd probably use a 90/4 Makro Elmar, taking care to use the UV/IR filter, or maybe the 65/3.5 Elmar and a Viso III. And I'd light it carefully...
Cheers,
R.