A recruiting dinner is not only a great way for you to learn more about a company and it's employees, but it is also a testing ground for the company to see how you act in social situations. An important part of this test is how you present yourself, what you wear and your manners during the meal. Integral to this test is dressing properly.
Business casual attire is typically appropriate for a recruiting dinner. If the dinner is hosted at a more formal restaurant, a jacket is recommended. Wearing a darker colored shirt is also recommended in the event you spill something on yourself. Even if everything else goes well, future employers may form a bad opinion of you if you end the evening with a highly visible stain on your shirt.
Avoid white or other light color shirts that may show spilt drinks or food
Check with the restaurant ahead of time to see if a jacket is required
Consider ordering something solid so you don't spill all over your new clothes