Most children are familiar with Dr. Seuss and "Green Eggs and Ham." You could use some of the catchy phrases there.
Here are some children's songs about food to give you ideas. Select a tune they all know and make up some lines with the vocabulary you want to teach:
1. http://www.preschoolsings.citymax.com/foodsongs.html
2. http://www.kididdles.com/lyrics/food.html
3. http://www.everythingpreschool.com/themes/food/songs.htm
As for your 20 activities, start with something for the students to LISTEN to...you could make a short narrative with the vocabulary words. Then something where they will REPEAT. Any idea, flashcards, props, pictures for something to SEE. If you can put some pictures on the blackboard (chalk tray, for example), they can select which picture goes with what you say. A handout is good for coloring---color the eggs blue (for example). If you follow the sequence, add to the ideas I've already given you.
Sra