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Unformatted text preview: FDSC 394 Lecture Notes Updated 24 September 2007 24 August 2007 Review Syllabus and class expectations 27 August 2007 Review timeline in text, pointed out: 4000BC: Egyptians didnt know what they were doing in regards to enzymology or microbiology 1670s: van Leewenhoek wrote letters about his findings, was a drapier Up to 1880s: trying to figure out how things spoiled 1800s: Appert followed a process canning 1860s: Pasteur finally incorporated the field of microbiology, showed air contact caused contamination 1880s: Koch showed disease caused by organisms, Petri and Gram start to do real micro gives rise to the idea of CFU and standards in food safety 1950: Watson and Crick 1970-80s: S. Cohen and genetic recombination gives rise to biotechnology 1980s on: PCR, E. Coli O157:H7 and prions discovered Whats New? Bacterial genome: if you can define biology it is a powerful tool for looking at problematic organisms From list (found on his website) 1. food spoilage how processes can be made to reduce spoilage of food and maintain biology 2. risk assessment who consumes and who gets ill, highly variable, if you can define you can predict and tailor 3. biomedical forecast dependent on case 4. unknown causes of illness 5. quorum sensing bacteria understand whats in environment and respond as population cells -> biofilms 6. genomics will continue to be predominant in field to determine what may be new organisms. 29 August 2007 Played card game to discuss factors that affect illness People age, immune status, health status, genetics, geography Food water activity, temperature, pH, amount of bacteria present, energy, composition, type of bacteria, oxygen, competing flora, processing Bacteria which ones? Microbial Classification vanLeewenhoek made up, but is now done by direct microscopic observation- has some value, but still cant tell what it is Now there are a series of micro techniques (ex. Gram stain) used to give you answer of what it is Went over microbial phylogeny paper (highlighted some comments) and showed that it closely matches up with original phylogeny- notable exception: unable to say what will/will not make you ill even when following phylogeny, no notion of bacteria evolving to make us ill 31 August 2007 Microbial ecology Bacteria are found everywhere: showed examples of thermostable bacteria found in Yellowstone and in black smokers Thermus thermophilus interested in because of polymerase, enzyme found in a hot spring Ex: Importance of thermophiles in food- HFCS use high temperatures to process because of sterility and lowered viscosity, so less energy is used and reaction rates increase- Not always a good thing, but can be Watched video on J. Craig Venter bought boat and sailed around the world collecting bacteria 5 September 2007 N = N e t , where is the growth rate, which is complicated by substrate, environment, etc and is never constant...
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- Fall '05