Science of Food Safety: Microbes, Friend or Foe

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Science Objects are two hour on-line interactive inquiry-based content modules that help teachers better understand the science content they teach. This Science Object, co-developed between FDA and NSTA, is the third of four Science Objects in the Science of Food Safety SciPack. It explores how bacteria live in close concert with humans. Bacteria are masters at exploiting a variety of niches in the human body and live in huge colonies in places such as the skin, intestines and mouth. Most of these bacteria are harmless to the human body, and many are important in assisting its normal, healthy functioning. Disease in humans results when organisms such as bacteria interfere with the normal operation of the human body, most commonly foreign organisms entering the body. The human body has many mechanisms to protect itself against outside organisms that may interfere with its normal operation.

Bacteria that gain entrance to the body may form colonies in preferred organs or tissues, emitting harmful toxins as waste products. If the body's immune system cannot suppress a bacterial infection, an antibacterial drug may be effective—at least against the types of bacteria it was designed to combat. Viruses invade healthy cells and cause them to synthesize more viruses, usually killing those cells in the process.

  • Elementary
  • Middle

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Reviews (5)
  • on Wed Sep 03, 2014 5:50 AM

I really enjoy Science Objects. In 1-3 hours, the Science of Food Safety: Microbes, Friend or Foe Science Object will help me re-learn, refresh, or learn for the first time some critical science concepts I will have to know to obtain my Science Educator credentials. I appreciate that I can complete them at my own pace, and that, if used as park of a SciPack, I have access to a content expert to go to for help. The NSTA Learning Center Science Objects are very beneficial! Not only will they enrich my teaching, the knowledge will enrich my life.

Naomi Beverly  (Marietta, GA)
Naomi Beverly (Marietta, GA)

  • on Tue Jan 31, 2012 10:17 PM

Great overview of symbiotic relationships. The pictures and interactivity engaged my attention throughout the activity. Love the information on how the body’s immune system fights off invasive bacteria/pathogens. Excellent resource to use with scholars in the classroom.

Lorrie Armfield  (Laurel, MD)
Lorrie Armfield (Laurel, MD)

  • on Mon Jan 16, 2012 2:36 PM

I learned so much ! My college Nutrition textbook did not have half of the information on various microbes...loved the activities and pictures of bacterium

Katherine Jezidija-Kendall
Katherine Jezidija-Kendall

  • on Fri Nov 26, 2010 11:08 PM

This science object provides an overview of some ecological concepts including symbiotic relationships, many ways we utilize bacteria, strategies humans utilize to protect against pathogenic bacteria, and how the body’s immune system fights off pathogens. This object was a little shorter than most, but still provides good basic information. Some of the interactives and pictures (such as examples of symbiotic relationships, foods we use bacteria for, parts of the immune system diagram, and a food borne illness database) could also be used in the classroom.


  • on Tue Nov 09, 2010 8:14 AM

I liked this science object for the way it effectively compares the good, the bad, and the ugly of bacteria and viruses. Not all bacteria are bad; in fact, we would die without the assistance of many bacteria and their symbiotic relationships with us. Of course, there are also those that have deadly consequences, and enjoy the habitats found in the human body! Good tie-ins to ecology.

Jennifer Rahn  (Delafield, WI)
Jennifer Rahn (Delafield, WI)

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