Last time I was on SW there was one.
They do have barf bags, thanks. And I just got confirmation from my mom that no, they do not serve meals on Southwest flights. So if it's food related, it's something one of the passengers brought on-board.
Plus this:
http://www.independenttraveler.com/resources/article.cfm?AID=467&category=13
Southwest
"If your total flight itinerary includes a series of flights that each are less than two hours in duration, you will be served peanuts/pretzels on each flight segment. If your flight itinerary includes any nonstop flight longer than two hours, you will be served a packaged snack on that flight segment." The airline does not serve sandwiches or meals, however, you may bring something to eat onboard; it also serves complimentary coffee, juices, and cold drinks on all flights.