1. Plate 4 Germ Theory

2. Miasma During 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. Road sweeping was one way to help clean up the streets and hopefully prevent the spread of disease. http://www.sciencemuseum.org.uk/hommedia.ashx?id=7673&size=Small

3. The Problem 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 http://wpcontent.answers.com/wikipedia/commons/f/f6/Kombuchacultsm.jpg

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

5. Pasteur’s Experiment Pasteur boiled grape juice (w/ yeast) plugged and let cool – no growth When added just yeast then grape juice turned into good wine so he determined that yeast was necessary for wine http://www.icbm.de/~palmikro/mikrobiologischer-garten/pics/hefe_ph.jpg

6. http://www.vinegarman.com/zoo_vinegar_bacteria1.shtml Bacteria are agents of change – they alone sour wine Acetobacter aceti bacteria turn alcohol and sugars into acetic acid Pasteur’s Experiment

7. Pasteur’s Conclusion Microorganisms might be agents that cause disease Pasteurization (rapid heating and cooling) retards spoilage by killing all living cells, does not kill spores of bacteria (milk, OJ, many food products)