As Americans chow down on buffalo wings, beer, quesadillas, and chips, during the Super Bowl Unilever thinks it’s found a flavor that will help them swallow a serious message.

The company is sending its venerable Hellmann’s mayonnaise back into the Super Bowl ad fray in a second effort to use the Big Game to get people at home to cut back on wasting food. In the ad, linebacker Jerod Mayo tackles people getting ready to toss out old food, telling them instead they can use Hellman’s to turn potatoes into potato salad. “Saturday Night Live” cast member...