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Copy of Microbiology Midterm Seminar

Pathogen Identification and Food Safety

Toni Alba

on 12 September 2012

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Transcript of Copy of Microbiology Midterm Seminar

Pathogens and Food Safety Selective Plating Technique What is a Pathogen? Works Cited
"Advanced Selective Plating Media - University of Maryland." Patent Searching and Invention Patenting Information. Web. 28 Nov. 2011. <http://www.freepatentsonline.com/7842496.html>.
"Bacteria and Foodborne Illness - National Digestive Diseases Information Clearinghouse." Home - National Digestive Diseases Information Clearinghouse. Web. 28 Nov. 2011. <http://digestive.niddk.nih.gov/ddiseases/pubs/bacteria/#8>.
"Common Foodborne Pathogens - Iowa State University Extension." Iowa State University Extension and Outreach. Web. 28 Nov. 2011. <http://www.extension.iastate.edu/foodsafety/pathogens/index.cfm>.
"Enrichment Culture." Web. 24 Nov. 2011. <http://www.clt.astate.edu/dgilmore/Research%20students/enrichment_culture.htm>.
"Foodborne Diseases." National Institute of Allergy and Infectious Diseases Home Page. Web. 28 Nov. 2011. <http://www.niaid.nih.gov/topics/foodborne/pages/default.aspx>.
"For Educators | Competencies | General | Food Processing | Untitled." Food Safety Education. Web. 28 Nov. 2011. <http://www.foodsafetysite.com/educators/competencies/general/foodprocessing/processing2.html>.
"Pathogens 101 | STOP Foodborne Illness." STOP Foodborne Illness | America’s Voice for Safe Food. Web. 28 Nov. 2011. <http://www.stopfoodborneillness.org/content/pathogens-101>. A pathogen is defined as any "disease- producing agent"
This could be viral, fungal, or parasitic, but we mainly worry about BACTERIAL pathogens Pathogenic contamination poses a major threat to any food source.
Selective plating technique is similar to cultural enrichment in that it puts identical cultures under different conditions in order to view the reactions of the organisms to the changed variable. In selective plating, one culture of the organisms is replicated in a second petri dish, of which the variables have arleady been changed. Thus, it is the growth of te culture that is affected in the selective plating process and what allows for experts to determine or distinguish the culture. Many methods are used to identify pathogens. Laboratories use multiple methods in identifying pathogens, such as cultural enrichment or selective plating techniques. Identification by these processes can be either biochemical or serological. Cultural Enrichment Technique Other Methods of Classification Prime Suspects Common Illnesses How to Avoid Pathogenic Contamination Identifying pathogens through cultural enrichment are the most traditional forms of identification, but also the slowest. When it comes to food safety, cultural enrichment Though new tecniques are being developed, cultural enrichment often proves to be the one and only option in many cases. In the most common form of cultural enrichment technique, individual cells of bacteria are spread out onto a plate on which they multiply into visible colonies. These colonies are assumed to be identical to each other and therefore able to produce a pure culture. The cultures are then put under different situations, such as modified physical conditions or physical conditions, in order to isolate and distinguish any other unknown organisms in the sample or to distinguish and classify the culture from another. Pasteurization
Nucleic-acid based pathogen tests
Pathogenic Screens
DNA Hybridization Processes such as pasteurization reduce the risk of food contamination
by using heat to kill bacteria. Commonly pasteurized foods include
milk (and its products) and eggs. These products frequently carry
bacteria that cause typhoid fever, tuberculosis, scarlet fever, polio,
and dysentery. Salmonella
Escherichia Coli
Cryptosporidium Bacteria growth can be prevented in several ways:
•Promptly refrigerate food
•Cook food to appropriate temperatures
•Prevent cross contamination
•Wash surfaces, dishes, utensils,
•Wash all fruits and vegetables Botulism is caused by Clostridium botulinum bacteria. While it is a rare illness, with only 10-30 cases being reported annually, the nerve-targeting symptoms of Botulism can be severe and even life threatening.
Campylobacteriosis is an illness caused by Campylobacter contaminated food. Symptoms include diarrhea, nausea and vomiting, fever, tiredness and can last anywhere from 2-10 days.
E. Coli can be caused by several dangerous forms of E. coli, such as E. coli 0157:H7, which is found in the intestines and digestive tracts of many mammals. Symptoms of E. coli include nausea, abdominal cramps, bloody diarrhea, and extreme tiredness, with most cases lasting from 2-8 days and most victims recovering completely.
Hepatitis A is a disease that targets the liver. With almost 25,000 cases reported annually, the illness can produce full recoveries or even deaths. It is spread by the hepatitis A virus which can be spread by the blood of contaminated victims or through contaminated food.
Salmonellosis most often occurs in small outbreaks which most often target elderly people or small children. While it occurs worldwide, it is most common in North America and Europe. It is an illness caused by dangerous strains of the Salmonella bacteria such as S. typhimurium and S. enteritidis. While reports of outbreaks are decreasing, more and more resistant strains are being reported.
Shigellosis is caused by the four main types of Shigella bacteria-S. flexneri, S. boydii, S. sonnei, and S. dysenteriae. Outbreaks of this illness are most common in tropical climates but have occured in any place with poor hygiene, such as daycare centers and public areas. BACTERIA GOOD
(Probiotics) BAD
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