Tesco has been fined £7.6m for selling food past its 'use by' date.  This is a big fine which might have been reduced if the Court had allowed expert evidence in mitigation. 

I wrote an article last year on the issue of use by dates following the Court's preliminary ruling in the Tesco case which prevented reliance on such evidence: Is it time to review food use-by dates?   The Court ruled that there is a presumption that food past its use by date is unsafe for human consumption and this presumption cannot be rebutted by expert evidence to the contrary, even where a 'short' date has been used for quality purposes, rather than for reasons of safety.