The CIW's current campaign is focused on the major grocery chains across the company. After having major successes with various restaurant chains (most notably McDonald's, Taco Bell, and Burger King), the CIW shifted their focus. Since then, 6 companies have joined (including Good Foods). Now they're focusing on other major retailers, including Kroger.
This presents an opportunity to SSU. One of the primary actions on the CIW website is printing out a letter and giving it to the manager. This, I presume, is aimed to create consumer pressure on store-level managers, agitating them enough to bring this up with regional managers, etc. Sort of like climbing the pyramid. Here's the link to the printable letter: http://www.ciw-online.org/Resources/supermarkets/manager%20letters/kroger.pdf
Other options include printing off a postcard and mailing it to Kroger HQ. We could also rally/protest/table outside a Kroger location. However, I think our best option is obtaining an educational DVD and screening it, and then presenting either post cards or manager letters at the movie presentation.
Here's the action page on the CIW website: http://sfalliance.org/action.html