Preservation Power of Honey Discuss with a partner

Preservation Power of Honey

Discuss with a partner • Why does food spoil? • What conditions make this more likely?

How do we prevent the following foods from spoiling? • • • Beef jerky Bread Milk Pickles Raw steak Cucumber Cupcakes Croutons Twinkies

What does bacterial growth look like? Petri dishes with growth medium Bacteria growing in a petri dish

What is a zone of inhibition? • Bacteria is evenly applied to growth medium in a petri dish • Antibiotic discs are added • Petri dish is incubated to promote bacterial growth • Zone of inhibition: the area around the disc that contains no bacterial growth Antibiotic disc Bacteria growing No bacteria growing

Measuring effectiveness of antibiotics Antibiotics are not equally effective against all types of bacteria. Some work better than others. How might we judge if antibiotics are effective or not?

Measuring a zone of inhibition Use a metric ruler to measure the diameter of the empty area surrounding the disc in millimeters • If no bacterial growth was inhibited, report the size of the disc • What are the sizes of zones of inhibition pictured here?

Honey What have we learned about honey? How can we apply what we learned to benefit society?

Turbidity What is turbidity? How does measuring turbidity help us to determine bacterial growth in milk?

Image credits • Milk: https: //pixabay. com/en/milk-glass-drink-fresh-beverage-435295/ • "Good Food Display - NCI Visuals Online" by Unknown - This image was released by the National Cancer Institute, an agency part of the National Institutes of Health, with the ID 2397. Licensed under Public Domain via Commons - https: //commons. wikimedia. org/wiki/File: Good_Food_Display__NCI_Visuals_Online. jpg#/media/File: Good_Food_Display_-_NCI_Visuals_Online. jpg • "Agar Plate" by Y tambe - Y tambe's file. Licensed under CC BY-SA 3. 0 via Commons https: //commons. wikimedia. org/wiki/File: Agar_Plate. jpg#/media/File: Agar_Plate. jpg • "Agar plate with colonies". Licensed under Public Domain via Commons https: //commons. wikimedia. org/wiki/File: Agar_plate_with_colonies. jpg#/media/File: Agar_plate_with_colonies. jp g • "Bacterial lawn 01". Licensed under Public Domain via Commons https: //commons. wikimedia. org/wiki/File: Bacterial_lawn_01. jpg#/media/File: Bacterial_lawn_01. jpg • Ruler: http: //biologyasifitmattered. blogspot. com/2011/09/how-to-use-microscope-at-our-school-we. html • Measuring zones of inhibition: http: //www. cdc. gov/std/gonorrhea/lab/diskdiff. htm • "Runny hunny" by Scott Bauer, USDA ARS. Licensed under Public Domain via Commons https: //commons. wikimedia. org/wiki/File: Runny_hunny. jpg#/media/File: Runny_hunny. jpg • Turbidity vials: http: //water. usgs. gov/edu/turbidity. html