Target Grade Level / Age Range:
Students will identify possible food safety threats (microbial and/or chemical sources) and how to reduce the risk of those threats in crops like apples.
- My Family’s Apple Farm book by Katie Olthoff https://www.iowaagliteracy.org/tools-resources/publications
- Copies of Steps to Safe and Healthy Fruits and Vegetables (1 per student) https://www.cdc.gov/foodsafety/pdfs/fruit-veggie-safety-poster-85x11-508c.pdf
- Crayons, markers, pens, pencils
- Poster board – 4 pieces
- Optional props for demonstration activity
- rubber gloves
- long sleeve shirt
- safety glasses
- empty bottle of insecticide
- small measuring spoon
- plastic bee or other insect
- empty bottle of bleach or other cleanser
- real fruit/vegetables or plastic models
- bucket of ice
- two different shopping bags – one labeled ‘meat’ and the other labeled ‘fruits/vegetables’
- soap and water or hand sanitizer
- scrubbing brush
- timer/stop watch
- two boxes; one labeled ‘meat’ and the other labeled ‘fruits/vegetables’
- two cutting boards
Essential Files (maps, charts, pictures, or documents)
- My Family's Apple Farm: https://www.iowaagliteracy.org/tools-resources/publications
Vocabulary (with definitions)
- Food safety – scientific discipline describing handling, preparation, and storage of food in ways that prevent food-borne illness.
- Food-borne disease – the occurrence of two or more cases of a similar illnesses resulting from the ingestion of a common food.
- Cross-contaminate – the process by which bacteria or other microorganisms are unintentionally transferred from one substance or object to another, with harmful effect.
- Bacteria – single-celled organism that can cause disease. Also known as germs, pathogens, or bugs.
Background – Agricultural Connections
Teachers should understand the entire food production chain and the points at which contamination can occur. It takes several steps to get food from the farm or fishery to the dining table. We call these steps the food production chain (see graphic). Contamination can occur at any point along the chain—during production, processing, distribution, or preparation.
Production: Production means growing the plants we harvest or raising the animals we use for food. Most food comes from domesticated animals and plants, and their production occurs on farms or ranches. Some foods are caught or harvested from the wild, such as some fish, mushrooms, and game.
Examples of Contamination in Production
- If a hen’s reproductive organs are infected, the yolk of an egg can be contaminated in the hen before it is even laid.
- If the fields are sprayed with contaminated water for irrigation, fruits and vegetables can be contaminated before harvest.
Fish in some tropical reefs may acquire a toxin from the smaller sea creatures they eat.
Processing: Processing means changing plants or animals into what we recognize and buy as food. Processing involves different steps for different kinds of foods. For produce, processing can be as simple as washing and sorting, or it can involve trimming, slicing, or shredding. Milk is usually processed by pasteurizing it; sometimes it is made into cheese. Nuts may be roasted, chopped, or ground (such as with peanut butter). For animals, the first step of processing is slaughter. Meat and poultry may then be cut into pieces or ground. They may also be smoked, cooked, or frozen and may be combined with other ingredients to make a sausage or an entrée, such as a pot pie.
Examples of Contamination in Processing
- If contaminated water or ice is used to wash, pack, or chill fruits or vegetables, the contamination can spread to those items.
- During the slaughter process, germs on an animal’s hide that came from the intestines can get into the final meat product.
- If germs contaminate surfaces used for food processing, such as a processing line or storage bins, germs can spread to foods that touch those surfaces.
Distribution: Distribution means getting food from the farm or processing plant to the consumer or a food service facility like a restaurant, cafeteria, or hospital kitchen. This step might involve transporting foods just once, such as trucking produce from a farm to the local farmers’ market. Or it might involve many stages. For instance, frozen hamburger patties might be trucked from a meat processing plant to a large supplier, stored for a few days in the supplier’s warehouse, trucked again to a local distribution facility for a restaurant chain, and finally delivered to an individual restaurant.
Examples of Contamination in Distribution
- If refrigerated food is left on a loading dock for a long time in warm weather, it could reach temperatures that allow bacteria to grow.
- Fresh produce can be contaminated if it is loaded into a truck that was not cleaned after transporting animals or animal products.
Preparation: Preparation means getting the food ready to eat. This step may occur in the kitchen of a restaurant, home, or institution. It may involve following a complex recipe with many ingredients, simply heating and serving a food on a plate, or just opening a package and eating the food.
Examples of Contamination in Preparation
- If a food worker stays on the job while sick and does not wash his or her hands carefully after using the toilet, the food worker can spread germs by touching food.
- If a cook uses a cutting board or knife to cut raw chicken and then uses the same knife or cutting board without washing it to slice tomatoes for a salad, the tomatoes can be contaminated by germs from the chicken.
- Contamination can occur in a refrigerator if meat juices get on items that will be eaten raw.
Mishandling at Multiple Points: Sometimes, by the time a food causes illness, it has been mishandled in several ways along the food production chain. Once contamination occurs, further mishandling, such as under cooking the food or leaving it out on the counter at an unsafe temperature, can make a foodborne illness more likely. Many germs grow quickly in food held at room temperature; a tiny number can grow to a large number in just a few hours. Reheating or boiling food after it has been left at room temperature for a long time does not always make it safe because some germs produce toxins that are not destroyed by heat.
Interest Approach – Engagement
Pass out copies of the My Family’s Apple Farm book to students or display the digital version on the screen in front of the entire class. Read the book together as a class assigning different students to read each page. Help students with any vocabulary that they may not be familiar with. More advanced readers can read the supplementary passages at the bottom of each page.
Ask students if they have ever gotten sick from eating food. Some may have, but most probably haven’t. If they haven’t gotten sick, explain that is because people who handle food take proper precautions to help keep people healthy. If a student has gotten sick it was likely because the proper steps weren’t taken. Ask students to brainstorm a list of ways to keep food safe and to not get sick. Capture ideas on the board or a large writing surface. Student responses may include washing the food, cooking the food, and others.
Ask students to re-read pages 10-21 silently to themselves. Students should pay attention to ways outlined in the text to keep the apples safe to eat. Ask each student to identify at least two ways the apples stayed safe to eat. After they do that, let them confer with a friend to see what answers they each came up with. Finally, ask the students to share what answers they found in the text and what page they were on. Capture all responses on the board or on a large writing surface and ask the students to capture the answers in their notebooks. The students should come up with the following:
- Clean the apples – page 10
- Cut off damaged areas – page 10
- Cooking the apples – page 10
- Sort the apples and remove damaged ones – page 11
- Put apples into a refrigerator – page 12
- Store in temperature and moisture-controlled area – page 12
- Keep apples in cold storage - page 12
- Wash your hands before eating – page 20
- Wash apples under cool, running water – page 20
- Use a brush to remove any dirt – page 20
- Wipe them with a clean, dry towel – page 20
Break the students up into four groups. Provide each group with markers, crayons, or other writing utensils and a large piece of poster board. Give each group a copy of the information below (1-4). Ask group #1 to create a poster on Clean, group #2 to create a poster on Separate, group #3 to create a poster on Cook, and group #4 to create a poster on Chill. Tell the students their poster should include information on the topic they are given. Encourage them to create a neat, visually pleasing poster to help inform their classmates about their topic. Once students begin work, circulate the room and monitor progress. Ensure each group understands the concepts on their section. Allow for approximately 10 minutes of work time.
- Clean: Wash your hands and surfaces often.
- Germs that cause food poisoning can survive in many places and spread around your kitchen.
- Wash hands for 20 seconds with soap and water before, during, and after preparing food and before eating.
- Wash your utensils, cutting boards, and countertops with hot, soapy water.
- Rinse fresh fruits and vegetables under running water.
- Separate: Don't cross-contaminate
- Raw meat, poultry, seafood, and eggs can spread germs to ready-to-eat foods—unless you keep them separate.
- Use separate cutting boards and plates for raw meat, poultry, and seafood.
- When grocery shopping, keep raw meat, poultry, seafood, and their juices away from other foods.
- Keep raw meat, poultry, seafood, and eggs separate from all other foods in the fridge.
- Cook: To the right temperature.
- Food is safely cooked when the internal temperature gets high enough to kill germs that can make you sick. The only way to tell if food is safely cooked is to use a food thermometer. You can’t tell if food is safely cooked by checking its color and texture.
- Use a food thermometer to ensure foods are cooked to a safe internal temperature. The United States Department of Agriculture determines safe cooking temperatures for food. Check this chart for a detailed list of foods and temperatures.
- 145°F for whole cuts of beef, pork, veal, and lamb (then allow the meat to rest for 3 minutes before carving or eating)
- 160°F for ground meats, such as beef and pork
- 165°F for all poultry, including ground chicken and turkey
- 165°F for leftovers and casseroles
- 145°F for fresh ham (raw)
- 145°F for fin fish or cook until flesh is opaque
- Chill: Refrigerate promptly.
- Keep your refrigerator below 40°F and know when to throw food out.
- Refrigerate perishable food within 2 hours. (If outdoor temperature is above 90°F, refrigerate within 1 hour.)
Thaw frozen food safely in the refrigerator, in cold water, or in the microwave. Never thaw foods on the counter, because bacteria multiply quickly in the parts of the food that reach room temperature.
Once students have finished their posters, regain the attention of the class and ask the groups one at a time to stand up and present their poster to the rest of the class. Be sure they explain the concepts behind the poster and ask each group clarifying questions. Applaud each group’s effort and collect the posters to be hung or displayed somewhere around the classroom.
For the next chunk of content, you can have one or two student volunteers act out the various descriptions. The rest of the students can take notes on what is being described. You may want to provide some props throughout (in italics) and rotate the student volunteers for each section (On the Farm, At the Grocery, At Home, Storing, Separating). Invite the volunteers to the front of the room. Provide them with the appropriate props. Read the passage and ask them to act it out.
- Produce Food Safety from the Farm to the Grocery Store to Your Table
- Fruits and vegetables are healthy to eat. But did you know that harmful germs, like Salmonella, E. coli, and Listeria, can sometimes be on fruits and vegetables? There are —steps that can help keep you healthy and your fruits and vegetables safer to eat—from the store to your table.
- On the Farm
- Farmers wear proper personal protective equipment if they mix and apply any chemicals like fungicides or insecticides on fruit to protect themselves. This may include gloves, long pants and shirt sleeves, safety glasses, and other clothing. (Possible props: rubber gloves, long sleeve shirt, safety glasses)
- Farmers try to use minimal chemicals when they spray for insects or fungus that can damage the fruit. The trace residue that may stay on the fruit can usually be washed off with cold running water. (Possible props: empty bottle of insecticide, small measuring spoon)
- Farmers try to sort out damaged fruit. If an insect pierces the fruit or if the fruit gets bruised or damaged, bacteria or fungus can get in and start to grow. (Possible props: apple, plastic bee or other insect)
- Produce is kept in temperature and humidity-controlled rooms as much as possible. This cool, dry climate helps minimize the growth of bacteria and fungus. (Possible props: thermometer)
- Farmers will clean and sterilize all equipment between each harvest. (Possible props: empty bottle of bleach or other cleanser)
- At the Grocery Store or Market
- Consumers should choose fruits and vegetables that are free of bruises or damaged spots, unless you plan to cook them. ((Possible props: real fruit/vegetables or plastic models)
- Consumers should choose precut and packaged fruits and vegetables that are refrigerated or kept on ice. (Possible props: bucket of ice)
- Shoppers should separate fruits and vegetables from raw meat, poultry, and seafood in your shopping cart and in your grocery bags. (Possible props: two different shopping bags – one labeled ‘meat’ and the other labeled ‘fruits/vegetables)
- At Home
- Wash your hands before and after preparing fruits and vegetables. (Possible props: soap and water or hand sanitizer)
- Wash or scrub all fruits and vegetables under running water before eating, cutting, or cooking. (Possible props: scrubbing brush)
- Fruits and vegetables labeled “prewashed” do not need to be washed.
- Storing Fruits and Vegetables in the Refrigerator
- Refrigerate cut, peeled, or cooked fruits and vegetables as soon as possible, or within 2 hours. Refrigerate within 1 hour if the temperature outside is above 90°F. (Possible props: thermometer and timer/stop watch)
- Use a refrigerator thermometer to make sure the temperature stays at 40°F or below. (Possible props: thermometer)
- Store fruits and vegetables away from, and not next to or below, raw meat, poultry, or seafood. These items can drip juices that may have germs. (Possible props: two boxes one labeled ‘meat’ and the other labeled ‘fruits/vegetables)
- Use Separate Cutting Boards
- Use a separate cutting board for fruits and vegetables that is never used for cutting or preparing raw meats, poultry, or seafood. (Possible props: two cutting boards)
- Wash cutting boards, countertops, and utensils with hot, soapy water before and after preparing fruits and vegetables. (Possible props: cutting boards, soap, water)
Wrap up the activity by thanking the volunteers. Review the information by asking students to share one thing they found surprising or didn’t previously know.
- Ask them how they will apply this information in their own lives. Will they start washing their hands before they touch food? Will they help their parents pick out undamaged fruit at the grocery? Will they put food in the refrigerator to store it?
- Ask them to pick one of these and write it in the form of a goal in their notebooks using a statement like “I will….” For example: I will wash my hands before touching fruits and vegetables.
Did you know? (Ag facts)
- Bacteria can multiply rapidly if left at room temperature or in the “Danger Zone” between 40°F and 140°F. Never leave perishable food out for more than 2 hours (or 1 hour if it’s hotter than 90° F outside).
Extension Activities (how students can carry this beyond the classroom)
- Distribute copies of the Steps to Safe and Healthy Fruits and Vegetables poster to each student. Challenge them to tape it to the refrigerator at home and leave it there for 30 days.
- Ask students to interview a farmer or home gardener. Ask them what chemicals they use on their crops fertilizer, herbicides, insecticides, fungicides, other pesticides. Ask them how they measure the amount of chemical and if they think it is a lot of chemical or a little chemical.
- The U.S. Department of Agriculture determines safe cooking temperatures for food. Ask students to write a short paragraph explaining how these guidelines and rules help keep people safe.
Suggested Companion Resources (books and websites)
This project was supported by the U.S. Department of Agriculture's (USDA) Agricultural Marketing Service through grant AM180100XXXG051. Its contents are solely the responsibility of the authors and do not necessarily represent the official views of the USDA.
Iowa Agriculture Literacy Foundation
Agriculture Literacy Outcomes
- T3.3-5.e. Explain the practices of safe food handling, preparation, and storage.
- T4.3-5.d. Provide examples of science being applied in farming for food, clothing, and shelter products.
Iowa Core Standards
- 21st Century Skills:
- 21.3–5.HL.1. Obtain, interpret, understand and use basic health concepts to enhance personal, family, and community health.
- 21.3–5.HL.2. Use interactive literacy and social skills to establish personal family, and community health goals.
- 21.3–5.HL.5. Demonstrate behaviors that foster healthy, active lifestyles for individuals and the benefit of society.
- Social Studies:
- SS.3.10. Explain how rules and laws impact society. (21st century skills)