What do you recommend to safely transport frozen & chilled foods?

Our nearest supermarket is at least 7 miles away. I would love to use my bike to do grocery runs, but I fear that anything frozen/chilled will get too warm before I can make it home. I estimate the trip would take about 45 minutes or so from market to home, allowing for added weight and no direct route available. Is this just not do-able with frozen/chilled cargo?

Any and all suggestions welcome, please.