KEEPING OUR FOOD SAFE Teacher s Guide

Transcription

1 KEEPING OUR FOOD SAFE Teacher s Guide LESSON OVERVIEW: Every day we consume food; some is prepared, some is fresh, some is cooked, and some is even raw like sushi. No matter the type of food we eat, we wish to be assured of a safe and dependable food supply. Some of the most serious threats to food safety come from things we cannot see with the naked eye bacteria. Special technology is needed to quickly, effectively, and accurately detect these dangerous microbes. This lesson will explain the technology of bioassays and their use in monitoring food safety. LEARNING OBJECTIVES Students will be able to: Develop a basic knowledge of the scientific dimensions of contamination and food safety Compare and contrast options for rapid detection of food pathogens Investigate 3M innovations for pathogen detection Synthesize and present to the class the best options for pathogen detection Demonstrate learning by presenting a pathogen-detection mechanism for a specific food and pathogen, and explain why detecting that pathogen is important

2 ACADEMIC STANDARDS: National Science Education Standards (SCES) Science in Personal and Social Perspectives Personal and Community Health The severity of disease symptoms is dependent on many factors, such as human resistance and the virulence of the disease-producing organisms. Selection of foods and eating patterns determine nutritional balance. Science and Technology Identify a problem. Evaluate the solution and its consequences. Communicate the problem, process, and solution. Common Core ELA Standards Writing: CCRA.W.4 Produce clear and coherent writing in which the development, organization, and style are appropriate to task, purpose, and audience. CCRA.W.7 Conduct short as well as more sustained research projects based on focused questions, demonstrating understanding of the subject under investigation. Speaking and Listening: CCRA.SL.4 Present information, findings, and supporting evidence such that listeners can follow the line of reasoning and the organization, development, and style are appropriate to task, purpose, and audience. Language: CCRA.L.6 Acquire and use accurately a range of general academic and domain-specific words and phrases sufficient for reading, writing, speaking, and listening at the college and career readiness level; demonstrate independence in gathering vocabulary knowledge when encountering an unknown term important to comprehension or expression.

3 MATERIALS: Interactive Lesson This presentation was created with Power Point so that it can be used in a variety of classrooms. If you are using a computer with an LCD projector, simply progress through the Power Point by clicking to advance. All of the interactive aspects of the presentation are set to occur on click. If you are using an interactive white board, simply tap on each slide with your finger or stylus to activate the interactive aspects of the presentation. In the notes for each slide there will be information on how to proceed. Student Module This self-paced module is incorporated in the lesson, as indicated in the Teachers Guide and Interactive Lesson. It can also be used independently.

4 PROCEDURE OUTLINE SLIDE 1: Inform students that in this lesson they will learn about pathogens and how they can contaminate our food.

5 ENGAGE SLIDE 2: In this section, you ll introduce students to the idea that even though something looks like it s clean, it might not be.

6 SLIDE 3: Tell students that at first glance means the first time you look at something. A glance is a quick look, so the phrase also implies that the first look was a quick one.

7 SLIDE 4: Ask students: Does this kitchen look clean? Then ask: What things might be in this kitchen that you can t see at first glance? Click to reveal the three places where bacteria can be found in this kitchen. Ask: What might happen if any of this bacteria got into your food?

8 SLIDE 5: Discuss with students what it means for something to be contaminated. Have the students work as a class to complete this graphic organizer, with you writing the responses. Alternatively, you can divide students into groups of 2 to 4 to fill in the graphic organizer. You can print this slide for the groups or make copies of the handout provided. When students are finished, discuss their answers. Provide a standard definition of the word.

9 SLIDE 6: Follow the same procedure on this slide that you used for the previous slide.

10 EXPLORE SLIDE 7: Tell students that In this section, they will learn more about contamination and pathogens.

11 SLIDE 8: Ask students to read the sources of contamination and discuss how each picture represents these sources. Worker hygiene: If food service workers don t wash their hands properly, they can contaminate food. Melted fat and juices: Raw meats may contain pathogens. If food service workers allow melted fat and juices to touch other foods, these pathogens could spread. Coughs and sneezes: Pathogens can spread quickly from one person to another through coughs and sneezes. Always use a tissue, and don t shake hands with anyone or touch food if your hands are contaminated. Mishandling of foods: If food service workers handle foods without gloves, they could spread pathogens to the food. In addition, foods should be

12 stored in the proper manner and at the right temperature. SLIDE 9: Share some information with the students about bioassays. A bioassay is a test to determine the strength or activity of a substance. There are two types of bioassays: quantal and graded. o A quantal assay has a definitive all or none result. For example, in a drug toxicity bioassay, a drug either kills the animal test subject or it doesn t. o With a graded bioassay, the response is proportional to the input. For example, in a dosage bioassay, the effect of the drug increases as the dose increases. Bioassays can be used to determine many things, including the amount or concentration of a substance (such as a pathogen) present, toxicity levels (such as with medications or pollutants), and determining biological or chemical activity (such as the effect of

13 enzymes on substrates). For more detailed information about these pathogens and bioassays, visit this Web site: SLIDE 10: ale=en_ww&lmd= &assetid= &ass ettype=mmm_image&blobattribute=imagefile Inform students that in this activity, they will learn about four different foodborne pathogens: Salmonella, Listeria, Campylobacter, and Pseudomonas.

14 SLIDE 11: Divide students into small groups. You may wish to divide the class into 4 or 8 groups, depending on your class size. Assign each group one of the four pathogens being discussed in this lesson: Salmonella, Listeria, Campylobacter, and Pseudomonas. You may wish to print this slide out for the groups, or leave it displayed as they work. Student exploration of bioassays should include the quick-assay version (as described in the url shown in the notes on the previous screen) and the more rigorous version that would take several days.

15 EXPLAIN SLIDE 12: In this section, students will prepare and present their findings.

16 SLIDE 13: Direct student groups to share their findings in a PowerPoint or poster presentation. Tell students to consider the tips on this slide for giving a good presentation.

17 EXTEND SLIDE 14: In this section, students will compare and contrast pathogens.

18 SLIDE 15: Lead a discussion with the class, comparing and contrasting the four pathogens. Use the information students presented to the class as a foundation for the discussion. Use the points on this slide to guide the discussion. You may wish to ask the students to provide other points to discuss.

19 EVALUATE SLIDE 16: In this section, students will research an actual incident of food contamination.

20 SLIDE 17: Allow students Internet access for research. Some good online sources include:

21 You may wish to assign this as in-class work or as homework. SLIDE 18: You may wish to share this rubric with students before the assignment.

22 KEEPING OUR FOOD SAFE Understanding the Sources of Contamination Definition Characteristics Examples Non-Examples

23 KEEPING OUR FOOD SAFE Organizer for Pathogen Characteristics, Detection, and Symptoms Pathogen Foods Contaminated by Pathogen Human Symptoms When Infected by Pathogen Existing Methods for Food Analysis and Detection of Pathogen