I.   Grade/Course Title: 7th Grade Science


      a. Course Overview/Description: ______________________________________________________


      b. Quarter: Four


II. Unit #7    MICROBES/FOOD PRESERVATION Unit Length: 5 weeks


      a. Unit Introduction: Certain microorganisms or microbes can be harmful to humans and food production. When a microbe enters an organism and reproduces an infection, contamination and food spoilage can result causing serious problems. These infections can be transmitted from one organism to another. Microbes can be controlled through several approaches, leading to removing them, killing them, or preventing them from growing. These control measures change or alter the abiotic factors needed for growth of the microbe. 


      b. Standards for Unit #7

       C 21. Describe how freezing, dehydration, pickling and irradiation prevent food spoilage caused by microbes.

       CINQ6. Use mathematical operations to analyze and interpret data.

       CINQ7. Identify and present relationships between variables in appropriate graphs.

       CINQ9. Provide explanations to investigated problems or questions.

         CT State Grade Level Expectations (Draft)

CT State Grade Level Expectations (Draft)

GRADE-LEVEL CONCEPT:  u Various microbes compete with humans for the same sources of food.


  1. Microorganisms (microbes) are microscopic organisms, such as bacteria, yeast and mold, that are found almost everywhere: in air, soil and water, inside our bodies and in our foods. 
  2. Bacteria are single-celled organisms that differ from other single-celled organisms in that they do not have organelles such as a nucleus, mitochondrion or chloroplast. 
  3. Bacteria are an essential component of any food web because they break down complex organic matter into simple materials used by plants.  Some bacteria can produce their own food through photosynthesis and others are consumers that compete for foods that humans eat.
  4. Some bacteria can be beneficial to humans. Certain bacteria live symbiotically in the digestive tracts of animals (including humans) and help break down food. Other bacteria are used by humans to purify waste water and to produce foods such as cheese and yogurt.
  5. Some bacteria are harmful to humans. They can spoil food, contaminate water supplies and cause infections and illness.
  6. Food preservation methods are based on creating conditions that kill the bacteria or inhibit their growth. Food preservation methods include removing moisture by dehydration or salting, removing oxygen by vacuum-packing, lowering pH by pickling, lowering temperature by refrigerating or freezing, and destroying the bacterial cells by irradiation or heat (pasteurizing and cooking).
  7. Throughout history, humans have developed different methods to ensure the availability of safe food and water to people around the world. 



c. Essential Questions:

1. How can heat prevent microbes from growing?

2. Can microbes cause diseases?

3. What factors are necessary for microbial growth?


d. Essential Content/Concepts:

1. Microbes are very small organisms.

2. Certain microbes can cause diseases.

3. Diseases from microbes can be passed from one organism to another.

4. Some microbes are helpful to the environment.

5. Freezing slows the growth of microbes.

6. Irradiation kills microbes.

7. Altering abiotic factors limits reproduction in organisms.



 e. Essential Skills:

1.  Describe different methods that prevent food spoilage.

2. Identify relationships between variables in graphs.

3. Describe factors needed for microbial growth.




f. Vocabulary

microbe, microscope, infectious disease, freezing, dehydration, pickling, irradiation, food spoilage, abiotic factors, transmitted


g. Science Misconceptions

1. Microbes limit themselves to certain things.

2. Microbes are all harmful.

3. Microbes and viruses are one and the same.

4. Food spoilage is not caused by microbes.





       Microscope Lab with prepared bacteria cells


       Bacteria Gathering Lab





Dr. X and the 
Quest for Food Safety
Interactive Video (46:00 min.



Science And Our Food Supply: Curriculum







      Develop a timeline for different types of food preservation techniques

      Design a Brochure (Microsoft Publisher), outlining food preservation techniques

      Food Safety and Quality Projects




Introduction to Bacteria     


Reading for Information:

      Donít Eat That Sandwich

      Where Have All The Bees Gone?                      


IV.. Significant Tasks (ST) #/Title: Food Spoilage Significant Task

      a. Significant Task Introduction: A major way that people prevent food spoilage is through spices. For example, the list of ingredients on the jar of pickles includes vinegar, salt, sugar~ and spices. Do these ingredients help preserve the pickles?  This task will help the students answer this question can spices be used to control food spoilage.



      b. Length/Timing:


      c. Essential Questions: Can food spoilage be controlled?


      d. Assessment Tools (AT): Lab report



            Readings, Texts, Materials, Videos


Suggested Science Fair Topics


Example Assessment Questions

  1. Infectious diseases are caused by

a. microorganisms     b. poor diet   c. allergies   d. chemicals in the environment


  1. Which of the following methods may be used to kill harmful bacteria in food?

a. freezing and refrigeration      b. wrapping and freezing

c. wrapping and bottling           d. pasteurizing and sterilizing


  1. Disinfection is a method used to

a. control infectious diseases            b. increase the number of bacteria

c. increase the rate of spoilage         d. spread diseases


  1. Describe two ways your life was affected by bacteria today.




5. Modern soaps contain chemicals that kill bacteria. Describe one good outcome and one bad outcome of the use of these antibiotics.





  1. Describe how pickling can be used to prevent food spoilage.