Agricultural Literacy Curriculum Matrix
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Preservation Power of Honey
9 - 12
Students will expand their knowledge of microbial growth and scientific food preservation methods to learn how honey can serve as an antibacterial agent. Students will learn how honey may be used as a preservative of milk in areas without access to electricity or refrigeration and how this preservation method relies on elements found specifically in honey that cannot be replicated with other sources of sugar.
- Internet access
- Preservation Power of Honey student worksheet, 1 copy per student
- Preservation Power of Honey Teacher KEY
- Preservation Power of Honey PowerPoint
Essential Files (maps, charts, pictures, or documents)
- Preservation Power of Honey PowerPoint
- Preservation Power of Honey Teacher KEY
- Preservation Power of Honey student handout
turbidity: a measure of relative clarity of a liquid
preservative: a substance added to a product to destroy or inhibit multiplication of microorganisms
microbe: a microscopic living organism—e.g., bacterium, fungus, protozoan
zone of inhibition: the area around an antimicrobial disc that contains no bacterial growth
Did you know? (Ag Facts)
- If properly stored, honey will not spoil. A pot of honey found in an ancient Egyptian tomb was proved to be as wholesome as fresh honey.1
- Honey is the ONLY food source produced by an insect that humans eat.1
- Methods of food preservation have permeated every culture and nearly every time period.2
Background Agricultural Connections
Interest Approach – Engagement
- Project the Preservation Power of Honey PowerPoint. Show students slide 2 and have students review with a partner the following two questions:
- Why does food spoil or go bad? (Microbial growth, usually from bacteria)
- What conditions make this more likely to happen? (Unsanitary conditions, when food is kept in conditions favorable for bacterial growth (temperature, moisture, etc.) when food is not cooked thoroughly enough)
- Give each student one copy of the Power of Honey student handout. Using page one of the handout and slide three of the PowerPoint, introduce the list of foods- beef jerky, bread, milk, pickles, raw steak, cucumbers, cupcakes, croutons, and Twinkies.
- As a class, discuss what makes food spoil. Have students work individually to predict how they believe these foods are preserved.
- Discuss answers as a whole class and record effective food preservation strategies. Answers are provided in the teacher notes, however, students may come up with additional or creative food preservation techniques. Students should discuss removing water (dehydration), keeping out air (sealing), refrigeration, increasing acidity (adding vinegar), and adding preservatives.
Activity 1: Measuring antibacterial properties of honey
- Using the paragraph on page one of the handout, introduce how bees gather their food from flowers during the spring, summer, and fall, but must protect this food for use during dearth periods.
- Have students predict and write down which preservation methods they think bees might use.
- Listen online to the audio clip “Why Honey Doesn’t Spoil.” Discuss if their predicted answers matched those in the audio clip. (Bees use dehydration by removing water from nectar. This could also be described as highly concentrating the sugars in honey. Students will not be introduced to it yet, but bees also keep out water by sealing honey in honeycomb cells with a wax capping and by adding an enzyme that produces hydrogen peroxide).
- Review how to grow a colony of bacteria on agar in petri dishes (use slides 4-6 of the PowerPoint for visual support). Point out how antibiotic discs can be applied to a petri dish to inhibit bacterial growth (if the bacteria are susceptible to the antibiotic in the disc). Facilitate student discussion of how antibiotics might be tested in the lab for their efficacy against bacteria. (Measuring and comparing the zones of inhibition for different antibiotics is one way.)
- Show students how to measure the zone of inhibition (slide 7 of PowerPoint). (Use a ruler; measure area with no bacterial growth including the disc.)
- Divide students into pairs to complete "Part 1" of the worksheet. Students will measure zones of inhibition for each antibacterial disc and use their data to determine the relationship between concentration of honey and the size of the zone of inhibition.
- Facilitate a whole class discussion of what students observed from the experiment. (The higher the honey concentration on the disc, the larger the zone of inhibition, and therefore the fewer bacteria were able to grow.)
- Listen online to the audio clip “Honey: Food for Yeast or a Natural Preservative.”
- Guide discussion on why bacteria doesn’t thrive in honey. (By the process of osmosis, the high concentration of sugar in honey forces the water out of any yeast or bacteria cells, drying them out and destroying them.)
- Have students work in pairs again to predict if a concentrated sugar solution could be used as a more cost effective preservative. (Based on what they have observed and listened to so far, students will likely predict that sugar is a good substitute for honey as a preservative.) Have students provide evidence for their prediction.
Activity 2: Comparing sugar to honey
- Ask students to read the information found on page three of their handout to familiarize themselves with the sugar experiment setup explained in "Part 2" of the worksheet.
- Divide students into pairs to measure zones of inhibition for each antibacterial disc and use their data to determine the relationship between concentration of sugar and the size of the zone of inhibition. (There is no effect of the concentration of sugar on the growth of bacteria.)
- Ask students to compare the effectiveness of honey to a concentrated solution of table sugar and provide evidence to support their choice. (Honey was an effective antibacterial, however, concentrated sugar was not effective at inhibiting bacterial growth.)
- Discuss if students thought this would be the case. Why or why not? (Based on information presented so far, this should be surprising to students. Honey must be more than simply a source of concentrated sugar.)
- Read and discuss as a class how nectar is ripened into honey from the student worksheet and have students predict if there is anything special about honey.
- Have students discuss why honey and concentrated sugar might have had different effects on bacterial growth. Examine the honey ripening diagram. Have students note that hydrogen peroxide and acid are produced by the addition of an enzyme, glucose oxidase.
- What do we use hydrogen peroxide for? (Cleaning bacteria from wounds)
- How have we used acid in food preservation? (Vinegar is used to pickle foods to prevent bacterial growth.)
- Have students predict which components found in honey may have inhibited bacterial growth on their worksheet.
Activity 3: Can honey inhibit the growth of bacteria in food products?
- Lead a discussion to review what has been learned about honey and how we might use what we have learned about the antibacterial properties of honey to benefit society (slide 8 of the PPT). (Answers may vary. Honey could be used as a wound dressing in hospitals or as a food preservative in areas without access to other means of food preservation such as refrigeration.)
- Have students read part 3 of the student worksheet about an experiment testing honey as a preservative for milk. Discuss the following (slide 9 of PowerPoint):
- What is turbidity? (Turbidity is a measure of how clear a liquid is.)
- How does measuring turbidity help us to determine bacteria growth in milk? (Turbidity is an indicator of bacterial presence; the cloudier a liquid is, the higher the turbidity, the more bacterial is assumed to be present.)
- Instruct students to calculate the percent difference in turbidity of milk with honey compared to milk without honey as a sign of inhibition of bacterial growth. Use this data as evidence when answering the two follow-up questions.
- Facilitate class discussion about the feasibility of using honey as an effective preservative for milk. Have students make a list of benefits and challenges. (Potential benefits include availability of an inexpensive, protein-rich food source in areas with no refrigeration, better bone and teeth health, access to calories in areas dealing with malnutrition; potential challenges include cost of adding honey, change in flavor of milk, consumer acceptance of this new method for preservation.)
- Using the class discussion as a starting point, have students complete the final question on the worksheet on their own. Encourage students to think critically about this issue.
Concept Elaboration and Evaluation
- Many areas throughout the world suffer from hunger due to an inability to properly preserve and store their food.
- Honey is produced by bees and can be used to preserve foods.
- Methods of food preservation include dehydration, sealing, refrigeration, increasing acidity, or adding a preservative such as honey.
We welcome your feedback! Please take a minute to tell us how to make this lesson better or to give us a few gold stars!
Students can be given time to explore the government website, http://www.foodsafety.gov/ to better understand sources of food contamination and how government agencies are involved in food safety.
Read the article “Why you shouldn’t take your milk’s three-week shelf life for granted” and discuss the challenges faced in developing countries when trying to preserve a perishable food item like milk.
Suggested Companion Resources
- Imported Food Safety (Activity)
- Honey Bee Study Prints (Poster, Map, Infographic)
- Amazing Time-Lapse: Bees Hatch Before Your Eyes (Multimedia)
- How It's Made: Honey (Multimedia)
- TedTalk- The First 21 Days of a Bees Life (Multimedia)
- Virtual Food Safety Labs (Multimedia)
- Gourmet Lab: The Scientific Principles Behind Your Favorite Foods (Teacher Reference)
- Food Safety A to Z Reference Guide (Website)
- Pollen Gallery (Website)
Agricultural Literacy Outcomes
Culture, Society, Economy & Geography
- Compare and contrast the economic challenges facing developed and under-developed countries (poverty, population, and hunger) (T5.9-12.c)
Food, Health, and Lifestyle
- Describe the nutritional value that can be added by processing foods (T3.9-12.c)
- Provide examples of foodborne contaminants, points of contamination, and the policies/agencies responsible for protecting the consumer (T3.9-12.h)
Common Core Connections
Reading: Anchor Standards
CCSS.ELA-LITERACY.CCRA.R.7Integrate and evaluate content presented in diverse media and formats, including visually and quantitatively, as well as in words.
Food Products and Processing Systems Career Pathway
FPP.01.03Apply food safety procedures when storing food products to ensure food quality.
FPP.03.02Design and apply techniques of food processing, preservation, packaging and presentation for distribution and consumption of food products.
Health Standard 5: Demonstrate the ability to use decision-making skills to enhance health.
5.12.1Examine barriers that can hinder healthy decision making.
World History Era 9 Standard 2A:Population explosion and environmental change alter conditions of life around the world.
Objective 3Assess why scientific, technological, and medical advances have improved living standards for many yet hunger, poverty, and epidemic disease have persisted.
HS-ETS1: Engineering Design
HS-ETS1-1Analyze a major global challenge to specify qualitative and quantitative criteria and constraints for solutions that account for societal needs and wants.