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Science and Our Food Supply- Middle School Guide: Up Front

Science and Our Food SupplyTeacher's Guide for
Middle Level Science Classrooms

2007 Edition

Return to Table of Contents

 Welcome to
SCIENCE AND OUR FOOD SUPPLY

You and your students are about to experience a unique program that makes food safety an integral part of your science curriculum.

Food Safety = Science!

When it comes to making science relevant for your students, what better way than to apply it to something that's part of their everyday lives? Food gives you an ideal springboard for bringing a host of science concepts to life in your classroom!

Science and Our Food Supply includes timely food safety science that you won't find anywhere else. It takes the methods of real-life scientists who are working every day to keep our food supply safe - and turns their strategies and goals into hands-on experiences for your own students.

Science and Our Food Supply is classroom-tested. It was developed in conjunction with an experienced team of middle level science teachers.

You'll find in-depth activities and experiments covering a broad range of topics, including:

  • Bacteria, including Foodborne Pathogens
  • Pasteurization Technology
  • The Science of Cooking a Hamburger
  • DNA Fingerprinting
  • Outbreak Analysis

 

Food Safety Matters!...

To Everyone

In 1999, the Centers for Disease Control and Prevention (CDC) presented the following statistics on reported cases of foodborne illnesses in the United States:

  • 76 million gastrointestinal illnesses
  • 325,000 hospitalizations
  • 5,000 deaths

To Students

Fast-food restaurants employ more high school students than any other industry.

An awareness of food safety risks are especially critical if your students:

  • prepare their own food at home
  • prepare food for younger siblings or grandparents
  • prepare food for children in their care
  • work in restaurants, supermarkets, and other places that sell, handle, and serve food

Learning about food safety will help students better understand decisions and practices that can truly impact their personal health.

For Some, the Risks Are Even Greater

People in the following at-risk categories are more likely than others to get sick from harmful bacteria that can be found in food. And once they're sick, they face the risk of serious health problems, even death:

Nearly 25% of the U.S. population is at risk for serious symptoms from foodborne illness.

  • the elderly
  • young children
  • pregnant women
  • people with weakened immune systems

Plus, underlying illnesses, such as diabetes, some cancer treatments, and kidney disease may increase a person's risk of foodborne illness.

It's a Matter of Changing Times

There are many issues that make food safety more of an issue now than ever before. For instance:

  • Meals Prepared Away from Home – Today, nearly 50% of the money we spend on food goes toward buying food that others prepare - like "take out" and restaurant meals. Plus, a growing number of Americans eat meals prepared and served in hospitals, nursing homes, and day-care and senior centers.
  • Food from Around the Globe – Food in your local grocery store comes from all over the world, which may bring us new microorganisms. This presents a whole new set of modern food safety challenges.
  • Resistant Bacteria – In 1950, scientists knew of 5 foodborne pathogens. In 2000, there were at least 25 foodborne pathogens, including 20 newly discovered ones.

The Science and Our Food Supply program is your innovative classroom link between food . . . science . . . and health.

So let's get started!  down arrow

 

PROGRAM AT A GLANCE . . .

Now you can teach important science concepts using the timely topic of food safety with Science and Our Food Supply. It's a feast of food safety information and hands-on, minds-on lessons!

Inside you'll find a wide selection of inquiry-based lessons that provide you with several weeks of instruction. Guided by the National Science Education Standards, this program serves as a supplemental curriculum that can be easily incorporated into your Biology, Life Science, or other science classes. Your students will get the inside scoop on microbes - how they live, grow, and s-p-r-e-a-d. They'll go behind the scenes and be introduced to the latest food safety technologies that affect the foods they eat, and meet real-life scientists in a wide variety of science disciplines.

MODULAR FORMAT

The program is divided into the following 5 modules with activities and experiments related to each module:

  • Module 1 - Understanding Bacteria
  • Module 2 - Farm
  • Module 3 -Processing and Transportation
  • Module 4 -Retail and Home
  • Module 5 -Outbreak and Future Technology

COMPONENT CONNECTIONS

cover page of Teacher's Guide for Middle Level Science Classrooms

The following 3 components are designed to provide a variety of learning opportunities.

Science and Our Food Supply Teacher's Guide

  • Includes 15 hands-on, minds-on activities and experiments
  • Features fun, creative ways for presenting the lessons
  • Introduces fascinating facts about food safety
  • Guided by the National Science Education Standards

Dr. X and the Quest for Food Safety Video/DVD

Dr. X holding a small bird
  • Features a savvy food scientist (Dr. X) and student (Tracy) to introduce and reinforce the science concepts in the activities and experiments
  • Explores behind-the-scenes research in laboratories
  • Profiles scientists in food safety careers
  • Provides little-known, pop-up facts

BONUS! Check out the careers section following Module 5. It features more in-depth information about the scientists in the video/DVD.

Food Safety A to Z Reference Guide

Cover Page of Food Safety A to Z Reference Guide
  • Offers the most accurate, up-to-date information on food safety
  • Features an easy-to-use alphabetical format
  • Includes more than 100 terms
  • Presents practical, in-depth information on the 4 Cs of Food Safety (Clean, Cook, Chill, and Combat Cross-Contamination)
  • Introduces healthy practices for handling, preparing, cooking, and serving a variety of foods
  • Includes a vivid Farm-to-Table Continuum illustration
  • Showcases interviews with real-life scientists
  • Includes tips, fun facts, visuals, and answers to your most frequently asked food safety questions

 

HIGHLIGHTS OF YOUR TEACHER'S GUIDE

What's Inside . . .

Safety First offers tips and techniques for staying safe in the lab.

Lab Procedures highlights basic laboratory procedures for conducting the experiments.

National Science Education Standards Chart is an at-a-glance overview of all the activities/experiments and the National Science Education Standards that they cover.

SciLinks Logo

The National Science Teachers Association (NSTA) has launched a bold new project that blends resource materials and telecommunications into a dynamic new educational tool. This effort, called sciLINKS®, links specific supplemental resource locations with rich Internet resources. NSTA has incorporated sciLINKS into this supplemental curriculum. You'll find an icon in the Resources section of several of the activities and experiments with the sciLINKS URL (www.scilinks.org disclaimer icon) and a code. Go to the sciLINKS Web site, sign in, type the code from the page you are reading, and you will receive a list of URLs selected by science educators. Sites are chosen for accurate and age-appropriate content. The underlying database changes constantly, eliminating dead or revised sites or simply replacing them with better selections. The ink may dry on the page, but the science it describes will always be fresh!


Science Content begins each module with a review of the science content presented in the video/DVD. Fascinating facts are also featured. Read this section before watching the video/DVD module or conducting the activities and experiments.

Activities and Experiments

  • Activities explore food science concepts and encourage student creativity.
  • Experiments are based on scientific inquiry that explores real-life food science while teaching good scientific methods and laboratory practices.
  • SciLINKS® links Internet resources with the specific activity or experiment (see sidebar at left).
  • Student Sheets are reproducible and accompany several of the activities and experiments. A master lab report sheet that students can use for recording their observations, results, and other data is also included.

Resources Lists videos, reference books, science supplies, and more. In addition to this listing, check out  Science and Our Food Supply for a multitude of Web resources.

 

Connections to the National Science Education Standards

During the production of this curriculum, developers and educator reviewers recognized the need to connect this program to the National Science Education Standards (NSES). The National Standards provide the guidance for many state and local science education frameworks for what science content should be taught at particular levels and what students should be able to do and to understand.

You should carefully examine local and state frameworks and curriculum guides to determine the best method of integrating Science and Our Food Supply into the science program of your school. The Program and System Standards provided in NSES will be helpful in this determination. Appropriate placement within the scope and sequence context of a school's curriculum will optimize the interdisciplinary connections and enhance the ability of a student to learn key science concepts.

ACTIVITIES AND EXPERIMENTS

User-Friendly Format

The activities and experiments are written in this easy-to-understand format:

activities and experiments pages illustrated with explanations for each of the headings within the section. See linked description

Watch for the following icons . . .

Empty flask and half-filled test tube in a green circle as background
Lab Experiment
Indicates a lab experiment
Hand holding a pencil in a green circle background
Activity
Indicates an activity
Video tape in a green circle background
Video
Show or review the video
SciLinks Logo
Links Internet resources with the specific activity or experiment
Career Connection icon with lab coat
See the interviews with real-life food safety scientists in the Food Safety A to Z Reference Guide


 

Safety First in the Laboratory

Preparing for the Lab Experiment

  • Wash your hands with hot, soapy water. If soap and water are not available, you can use disposable wipes or a hand gel sanitizer.
  • Wear disposable safety (protective) gloves.
    Disinfecting Bleach Solution: 20ml of liquid household bleach (chlorine bleach) in 1 L of tap water.
  • Tie back long hair.
  • Wear safety goggles or regular glasses for microbiology work.
  • If possible, wear a lab coat or apron.
  • NEVER EAT, DRINK, OR CHEW GUM IN THE LAB. Keep your hands, pencils, etc. out of your mouth.
  • Disinfect all surfaces with a disinfecting bleach solution before beginning an experiment (see box at right).

INAPPROPRIATE BEHAVIOR WILL NOT BE TOLERATED AT ANY TIME IN THE LAB!

Safety Gloves

  • Wear safety gloves when inoculating Petri dishes and when working with raw meat. Safety gloves are made using many types of materials, including vinyl, and polyethylene. They can be purchased at a local pharmacy, supermarket, or through science supply catalogues.
  • When removing safety gloves, be careful not to contaminate your hands, items, or surfaces with any residue that may be on the gloves.
  • Throw away used gloves immediately after removing them. Wrap one glove inside the other, then throw both gloves away.
  • Wash your hands with hot, soapy water after removing the gloves.

Hot Surfaces

  • Use thermal gloves or hot-pad holders when working with hot plates, burners, autoclaves, or any other heat source.

Petri Dishes

  • Always tape Petri dishes closed after inoculating them.
  • Never open a Petri dish with organisms growing in it. It could contain dangerous pathogens!

Pipettes

  • Never pipette by mouth. Always use a pipette bulb or pipette aid.
  • Be careful when attaching a pipette bulb. Hold your hand close to the end of the pipette where the bulb will be attached. Push the bulb on carefully and gently. If you push too hard, the pipette could break and you could cut yourself.

Food in the Lab

  • NEVER EAT OR DRINK ANY FOOD OR LIQUID USED IN AN EXPERIMENT.
  • Thoroughly wash hands before and after handling and cooking raw meat.
  • Wear safety gloves, safety goggles, and lab aprons when handling and cooking raw meat.

Proper Clean-Up

  • Wear safety gloves and take appropriate defensive measures when cleaning up cultures and used equipment.
  • Wash all glassware and other instruments in hot, soapy water. Then sterilize (see Sterilizing Equipment).
  • Properly dispose of used Petri dishes and other used equipment.
  • Thoroughly disinfect all surfaces, especially those that come in contact with raw meat.
  • Before leaving the lab, wash your hands with hot, soapy water or use a hand gel sanitizer.

Disposal of Used Materials and Equipment

  • Check your school, local, or state safety regulations for specific information on how to properly dispose of potentially hazardous materials. If there are no guidelines, follow these precautions:

For Raw Meat

  • Unless contaminated with a virulent pathogen in the lab, raw meat and other foods can usually be disposed in the regular solid waste. Place the meat in a sturdy plastic bag, seal, and dispose.

For Used Swabs, Petri Dishes, Pipettes, and Other Disposable Equipment

  • Use a sturdy plastic bag that won't leak.
  • Place the bag in a metal container, such as an empty coffee can. Use one bag/container for each team of students conducting the experiments.
  • Place used swabs, disposable Petri dishes, pipettes, etc. in the bag.
  • At the end of the lab, add a disinfecting bleach solution and tightly close the bag.
  • Dispose the closed bag in the trash.

Note: Equipment that will be reused should be cleaned using hot water and soap and then placed in boiling water for 10 minutes or sterilized in an autoclave.


 

Laboratory Procedures

Washing Hands

  • Use hot water.
  • Wet hands and add soap.
  • Scrub hands for 20 seconds away from the running water. Thoroughly scrub wrists, under fingernails, around nail beds, and between fingers.
  • Rinse hands under running water.
  • Dry hands thoroughly with clean paper towels.

Note: If necessary, alcohol disposable wipes or hand gel sanitizers can be substituted for soap and water.

Disinfecting

Disinfecting Bleach Solution: 20 ml of liquid household bleach (chlorine bleach) in 1 L of tap water.

To Disinfect Countertops:

  • Put solution in spray bottle and label the bottle, "Disinfecting Solution."
  • Wipe off counters to remove any visible soil.
  • Spray the disinfecting solution on counters and leave it on for 2 minutes.

Note: Use the solution within 24 hours then dispose it down the drain. Solution will lose its effectiveness in 24 hours.

Sterilizing Equipment 
(test tubes, pipettes, etc.)

Options:

  • Use an autoclave.
  • Use dry heat - 160° F to 180° F (71° C to 82° C) for 3 to 4 hours.
  • Use chemical agents, such as 5% bleach, ethyl or isopropyl alcohol, commercial disinfectants, or iodine solutions.

 

Inoculating a Petri Dish

1. Label

drawing of petri dish divided into 3 sections with labels

  • Divide the Petri dish into sections (if applicable), and label the bottom (agar side) of the dish using a permanent marker.
  • Label along the outer edges of the dish or the sections, so the labels don't interfere with viewing the organisms.

2. Inoculate

  • Use a sterile cotton swab* to wipe the surface or liquid being tested. Hold the cotton swab at one end - do not touch the end that will be used to inoculate the agar.
    * If you use a control plate, new, untouched cotton swabs are good to use. Inoculate the control plate with a new swab to check for any microbial contamination.

For a Dry Surface

  • Wet the swab by dipping it in boiled or sterile water. Then, wring out the swab by wiping it against the inside of the container. (If the swab is too wet, the liquid will flow into other sections and the microbial colonies will run into each other.)
  • Swab the dry surface.

For a Liquid

drawing of inoculation of nutrient agar with swab, showing back-and-forth motion

  • Dip the sterile cotton swab in the liquid. Then, wring out the swab by wiping it against the inside of the container.
  • Inoculate the nutrient agar using a back-and-forth motion, covering the entire area of the plate or section. Do not swab too close to the dividing lines for the next section.

3. Tape

  • Place the cover on the Petri dish and seal it closed using Parafilm or masking tape.

For Parafilm

Drawing of Parafilm strip being stretched around the outside edge of a petri dish

  • Cut a narrow strip and stretch it around the outside edge of the covered dish.

For Masking Tape

drawing of two pieces of tape attached to opposite sides of a Petri dish

  • Cut 2 small pieces of tape and attach them across opposite sides of the dish.

Note: Position the tape so you will be able to see the organisms without removing the tape.

4. Incubate

  • Place dishes upside down (label side up) in an incubator set at 35° C (95° F).

Helpful Tips for Viewing Inoculated Petri Dishes

  • Use a light box (ask a parent or shop class to make a light box for your class from plywood and Plexiglas; or, borrow a light box from the photography class).
  • Line up all the Petri dishes and compare the results.
    or
  • Use an overhead projector. Line up the Petri dishes on the projector and project onto a screen, so the entire class can view the results. This is very effective!
  • If neither a light box nor overhead projector is available, simply view the plates on a light-colored surface.


 

This chart highlights the way Science and Our Food Supply may be used to address the Science Content Standards found in the National Science Education Standards (NSES). It's designed as a chart instead of a checklist, since the degree to which a standard may be addressed by the activities is variable.

Note the relative rankings suggested by the educators who tested these activities. It became clear through the classroom testing and review process that this curriculum provided some especially good connections to several National Standards that are often missing in other science education resources. In particular, there seemed to be good alignment between the goals and activities of this curriculum and the standards related to Personal Health and Social Perspectives.

National Science Education Standards
Content
Standards
Module 1
Understanding
Bacteria
Module 2
Farm
Module 3
Processing and Transportation
Module 4
Retail and Home
Module 5
Outbreak and Future Technology
Eval-
uation Activity
The Big PictureBacteria Every-
where
12 Most
Un-
wanted
Bacteria
Chain of FoodBlue's the ClueMystery JuiceUltra
High
Pressure
Treat-
ment
Super-
market Smarts
Cooking Right
(The Science of Cooking a Ham-
burger)
A Chilling Invest-
igation
Crossed Up!Hands Off, Bactera!Out-
break
Alert
Beef Blast-
ers
Lose a
Million
Bacteria
The Game
Unifying Concepts and ProcessesSystems, order,
and organization
2332---333323-2
Evidence, models, and explanantion233333333332332
Change, constancy,
and measurement
23333333222233-
Evolution and equilibrium-11------------
Form and function23332223---233-
Science
as
Inquiry
Abilities necessary to do scientific inquiry121333333333322
Under
standings about scientific inquiry
121333333333322
Physical ScienceProperties
and changes of properties in matter
----213-1--1-3-
Motions and forces------3------3-
Transfer of energy------3------3-
Life
Science
Structure and function in living systems------------2--
Reproduction and heredity--13-----------
Regulation and behaviour-22------------
Populations and ecosystems--1------------
Diversity and adaptations of organisms-11---3------3-
Science
and Technology
Abilities of technological design22133233333233-
Under-
standings about science and technology
22133333333233-
Science in Personal
and Social Pers-
pectives
Personal
health
333333333333332
Populations, resources, and environments1123131-----322
Natural hazards333233-333313-3
Risks and benefits333333333333332
Science and technology in society33323333333233-
History
and
nature of science
Science as a human endeavor33323333333233-
Nature of science33323333333233-
History of science-21---2-----31-
Key Code
3 = Covers the Standard in Depth
2 = Covers the Standard
1 = Touches on the Standard

 


 

Description of format features for activities and experiments image.

  • TIME: The approximate amount of time needed for performing the activity or experiment. Time is designated in 45-minute class periods.
  • ACTIVITY OR LAB AT A GLANCE: Briefly summarizes the activity or lab experiment.
  • FOOD SAFETY CONNECTION: Relates science to actual food safety applications.
  • MATERIALS: Includes the items needed to perform the activity or experiment.
  • ADVANCE PREPARATION: Indicates what you need to do before conducting the activity or experiment.
  • INTRODUCTION: Provides fun, innovative suggestions for introducing the activity or lab. Suggested teacher dialogue is indicated by boldface italics.
  • PROCEDURE: Gives the step-by-step process for the activity or experiment. Suggested teacher dialogue is indicated by boldface italics. (Answers to questions are listed in parenthesis.)
  • TIME TO TUNE IN: Introduces the video/DVD module that’s relevant to the activity or experiment. It offers challenges students should look for as they watch the video/DVD.
  • SAFETY FIRST: Highlights important safety precautions when conducting the lab experiment.
  • INSTANT REPLAY: Uses interesting questions to guide students through a review of what they learned in the video/DVD, activity, or experiment.
  • SUMMARY: Summarizes key science concepts learned in the activity or experiment.
  • RESOURCES: Provides other resources for further study.
  • EXTENSIONS: Suggests activities for helping students learn more about the topic.
  • UP NEXT: Gives a sneak preview of the next activity or experiment.