Plate 4 Germ Theory

Define “miasma” and describe how it relates to the germ theory. Before the 1800s the miasma theory of disease dominated medical thought. It was believed that disease could be caused by the foul smells created by decomposing bodies, food, human waste, marsh gases and general filth. Also, ghosts and “evil spirits” were thought to get people sick. http://i.kinja-img.com/gawker-media/image/upload/s--BmERaXRR--/pconqcesdyjyfeprhfxe.jpg

Understand why requests from a local vineyard lead Pasteur to explain how diseases were transmitted. Wine did not have consistent flavors from one year to the next. Microscopic examination showed that yeast and bacteria were in spoiled wine and yeast alone in good wine. Yeast are the large cells and bacteria the small dots What is their size difference? http://wpcontent.answers.com/wikipedia/commons/f/f6/Kombuchacultsm.jpg

Vinegar The word "vinegar" derives from the Old French vin aigre, meaning "sour wine". http://www.touchofeurope.net/linens/Vinegars.html

Describe the steps of the experiments involving yeast and the production of good quality wine. Boiled grape juice (w/yeast) plugged and let cool no growth; when added just yeast (good wine) then grape juice turned into good wine so he determined that yeast was necessary for wine production. Also realized that boiling was important to remove all organisms. http://www.icbm.de/~palmikro/mikrobiologischer-garten/pics/hefe_ph.jpg

Describe the steps of the experiments involving bacteria and the spoilage of wine. Boiled grape juice - no growth. Added just bacteria - vinegar resulted. Bacteria are agents of change. They alone sour wine. These are the bacteria which turn alcohol and some sugars into acetic acid or vinegar. They are Acetobacter aceti. http://www.vinegarman.com/zoo_vinegar_bacteria1.shtml

Relate Pasteur’s work with wine to the transmission of diseases. They might be agents that cause disease. We have Pasteurization rapid heating and cooling – retards spoilage by killing all living cells, does not kill spores of bacteria (milk, OJ, many food products) http://www.wm.edu/news/images/photosets/striped%20bass/stripedbass-475x265.jpg

Pasteurization Heat shock kills bacteria but not spores. http://cdn4.explainthatstuff.com/how-pasteurization-works.png Heat shock kills bacteria but not spores. Pasteurized foods will NOT keep for a long time. http://www.tricklingspringscreamery.com/wp-content/uploads/2010/07/past-3.jpg