I added tooltips and zoom in this visualization, you can also get the zip code when mouse hovering an area but nodes. The color is from yellow to black. Actually every single record of low risk will be yellow, moderate risk will be green and high risk will be red, since some restaurant have multiple records, so the color will from yellow to black.
In this visualization, we can see the place with the heighest density is 94102, 94104 and 94111. It make sense because there have many company and shopping store. From this map, we can see most of restaurant are low risk but still have many restaurant have a worse situation. Combine with visualization1, the area of 94121 have some problem. This area have the most population but restaurant are rare and have poor quality. Maybe the government should pay more attention to the restaurant in this place and residents should carefully consider eating out. Look at 94110 the most number of enterprises area, it looks like even there are some restaurant have high risk, people still have many good choices to eat. I think 94112 is a special area. It have relatively high population and number of enterprises. Depend on this visualization the situation is better than 94121.