BioEd Online

Teacher Background

Simple precautions during food preparation can help to keep foods free of bacteria and also help to reduce the consumption of chemicals applied to fruits and vegetables. Some important food preparation tips include the following:

• Always rinse fruits and vegetables.

• Always wash hands before preparing any food and after handling raw meat, fish, or poultry.

• Always wash cooking utensils, such as knives and cutting boards, in hot, soapy water.

• Clean cutting boards and work surfaces with a 1:10 bleach and cold water solution to kill bacteria.

• Always wash cutting boards between preparing different food items.

• Cook all meats, fish, eggs, and poultry thoroughly.

• Use ground meats within 24 hours of purchase (or freeze them) and cook thoroughly.

• In home gardens, use pesticides as sparingly as possible.

• Avoid eating fish and seafood from polluted water.

This activity will allow students to observe safe food preparation practices while making a fun treat—ice cream!

Objectives and Standards

Concepts

• Simple things can be done during food preparation to reduce the risk of food contamination.

• Snacks can be nutritious and fun!

Science, Health, and Math Skills

• Measuring

• Planning a step-by-step procedure

• Making observations

Materials and Setup

Teacher Materials

• clean-up supplies

Materials per Student Team

• 6 tbs of rock salt

• 1/2 gal of ice

• clear, resealable plastic bag, freezer weight, 12 in. x 15 in. (gal size)

• measuring cups

• measuring spoons

Materials per Student

• 1/2 cup of whole milk

• 1/2 tsp of unflavored gelatin

• 1/4 cup of orange juice

• clear, resealable plastic bag, freezer weight, 4 in. x 6 in.

• plastic spoon

• tablespoon of sugar

• copy of "Good and Healthy!" sheet

Setup

1. Have students work in teams of two and share materials to freeze the ice cream. Each student, however, should prepare his or her own batch of ice cream.

2. Arrange measuring tools and ingredients along a counter, “cafeteria style.”

3. Students should practice safe food preparation procedures by using clean utensils, washing work surfaces, and washing hands before beginning. New resealable plastic bags do not need to be washed before use.

Procedure and Extensions

1. Before beginning, have students talk about ways they can keep food clean during preparation. List their ideas on the board. If necessary, mention additional points listed above to complete the discussion.

2. Tell students that they will be making one of their favorite foods—ice cream. Go over the steps they will follow to make the ice cream, as listed on the "Good and Healthy!" sheet. Have students identify which steps will require care to keep their food clean.

3. Before beginning, have students wash their hands and work areas.

4. Have each student measure the following ingredients into a small freezer-weight resealable plastic bag: 1/4 cup of orange juice, 1/2 teaspoon of gelatin, and 1 tablespoons of sugar. Have students seal then shake the bags to mix these ingredients together. Have each student add 1/2 cup whole, unflavored milk to his or her bag.

5. Have each team of two students fill a gallon-size resealable plastic bag about halfway with ice, and then add about 6 tablespoons of rock salt.

6. Direct both members of each team to place their bags inside the gallon bag with ice and seal the large bag carefully. Have students take turns shaking the gallon bags until the mixture freezes.

7. Let students remove the smaller bags, wipe or rinse off the salt water, and enjoy their sweet treat.

8. Later, have students write a paragraph describing the steps they followed to make the ice cream. Have them include descriptions of the ways they kept their food and work areas clean.

Extension

Let students bring raisins, chocolate chips, sprinkles, etc., from home to add to their ice cream. Or have them bring different kinds of fruit. A fourth-cup of mashed bananas or strawberries or another kind of juice can be substituted for the orange juice.

Handouts and Downloads