I've heard that it's not good to use the same board for vegetables and meat, not only when you are making a salad but in general. Something about the bacteria in dirt and the bacteria in the meat is a bad mix.
But I'm wondering if you are making a stew of some sort, where you need to boil both meat and vegetables together, can I safely use the same board for both?
I'm thinking since it will be cooked together anyways, what danger can there be?
I understand the intent of the advice to always keep meat and vegetable preparation tools and areas separate is to establish a habit, to avoid the possibility of cross contamination in cases where you are not going to be cooking the vegetables as much or at all; and similarly in a catering environment to be able to visibly demonstrate that working practices are such that cross contamination cannot occur.
I think that it is fine to use the same chopping board if the meat and vegetables are going into the pot at the same time. However, often recipes will call for the meat to be browned first and then the vegetables added. In these cases I would recommend using a different chopping board or thoroughly cleaning the chopping board between cutting the meat and vegetables.
I agree that it is a good practice to use separate chopping boards for meat and vegetables even if both will be cooked together, particularly if children or inexperienced cooks observe you cooking and may mistakenly think that it is fine to use the same board in all circumstances.