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11 Cards in this Set
- Front
- Back
Flash Pasteurization method
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Flash Pasteurization method - (HTST)
(1) HIGH Temperature/Short-Time method (2) 161 degrees F/ 15 seconds see CH 27 pg 820 |
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Vat Pasteurization Method
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Vat Pasteurization Method -
(1) LOW temperature (2) holding method (longer time) (3) 145 degrees F/ 30 MIN |
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Pour-plate method
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Pour-plate method -
(1) Serially diluted samples of milk are mixed w/sterile agar (2) Pour into sterile petri dishes (3) Incubate in order to view & count bacterial colonies in agar |
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How do you estimate the viable number of bacteria present in the original sample.
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Estimating viable # of bacteria:
"# OF COLONIES (on an agar plate)" x "DILUTION FACTOR of the sample" EXAMPLE: # of Colonies:(1/4 of petri dish =18) or 18 x 4 = 72 Dilution Factor: 10 ^4 (10,000) Viable Bacteria = 72 x 10^4 |
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Explain why just counting the # of bacteria (in milk) is NOT ENOUGH for judging the safety of the product?
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Problems that can be overlooked:
(1) low bacterial count DOES NOT mean bacteria are not PATHOGENIC (2) ANAEROBIC bacteria may NOT be counted (3) Bacterial clusters may form a SINGLE COLONY |
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If you observe very few colonies or too few colonies in a petri dish why does this happen?
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Errors in calculation:
(1) INACCURACY in pipetting- volume of milk may be inaccurate (2) CONTAMINATION- by using same pipettes in serial dilution |
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Give methods that can be followed while milking cows and storing milk to control the microbial growth in the milk
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To kill microbes:
(1) Flash pasteurization method (2) Vat pasteurization method |
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Give at least (3) pathogenic bacteria that could be found in the milk. What diseases do these bacteria cause?
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Pathogenic bacteria in Milk:
(1) Listeria monocytogenes CAUSES: Listerosis (2) Yersinia Enterocolitica CAUSES: Gastroenteritis (3) Campylobacter Jejuni CAUSES:Campylobacteriosis |
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Listeria monocytogenes
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Listeria monocytogenes (Gram +)
CAUSES: Listerosis GROWTH CONDITIONS: (1) Can resist extreme temp. Heat/Freezing SYMPTOMS (1) Flu-like symptoms (2) persistent fever (3) vomiting (4) diarrhea (5) nausea. |
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Yersinia Enterocolitica
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Yersinia Enterocolitica
CAUSES: Gastroenteritis SYMPTOMS: (1) similar to APPENDICITIS (2) vomiting (3) diarrhea (4) abdominal pain (5) fever |
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Campylobacter Jejuni
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Campylobacter Jejuni (Gram -)
CAUSES:Campylobacteriosis CONDITIONS: (1) Needs small amts of O2 to grow SYMPTOMS: (1) Bacterial diarrhea (2) abdominal pain (3) headache (4) muscle pain (5) nausea (6) fever |