A common question I get: how do you make food appear so fresh?
Well, I use fresh ingredients.
If fresh ingredients are not available, I go for frozen ones. Keep bowls of cold water handy and keep the vegetables in it (separated & sorted per bowl). This will keep them fresh looking for a bit longer. Make sure you get plenty to choose from & get somebody to assist you in the shoot, as things tend to get a bit messy & you need your hands clean to handle the photography gear.