Science and Our Food Supply: Investigating Food Safety from Farm to Table

4. 

Demonstrate how to sample the water and inoculate 

agar dishes (see page 8). 

5. 

Discuss the importance of a control dish. To test for 

bacteria in the water, swab half of the control dish with 

distilled water. Leave the other half untouched. 

6. 

Review the important rules of lab safety, especially the 

handling of inoculated Petri dishes (see page 8). 

7. 

Let each team develop its own hypothesis and design its 

own experiment. 

8. 

Let the students conduct their experiments. 

3

LAB:

 OBSERVE AND RECORD RESULTS     

1. 

Have teams observe their Petri dishes and record the 

results on a data table. 

2. 

Ask each team to present their findings to the class. List 

the class results and have the students compare their  

findings to the “Most Bac” and “Least Bac” lists from  

Lab 1. (Be sure to focus the discussion on the categories 

of items rather than on specific items.) 

3. 

Pose questions to guide students through a discussion. 

For example: 

• 

How did your original lists compare to the test results? 

Were there any surprises? What are your conclusions? 

• 

Could bacteria transfer from kitchen items to your 

food? Your hands? What might happen in these cases? 

• 

Why do certain kitchen items have more bacterial 

growth than others? 

• 

How do the data you collected relate to the 4 Cs of 

Food Safety? Which of the 4 Cs? 

• 

How could you reduce the bacteria on the items you 

tested? 

• 

What are your suggestions for avoiding cross- 

contamination in the kitchen? 

• 

What advice would you give to family members to 

help them prevent the spread of foodborne bacteria? 

MODULE 4:

 RETAIL AND HOME

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