Thursday, May 15, 2008

Cell Respiration Lab Ap Bio





A person who is going to hike an omelette prepared using egg farm. The tortilla is prepared the night before. Unfortunately, these eggs are contaminated in the shell with Salmonella enterica . By break to beat them there is an inoculation of these microorganisms in food. That person likes the tortilla curd is not everything, so that cooking does not end with the pathogenic bacteria found in the innermost part of the tortilla. When finished it, that person leaves the tortilla to cool to room temperature. At 9 am the next day, put the tortilla in a pan that you enter in your backpack and hiking.

Data: Number of

S. enterica in the shell: 1,000 cells per square millimeter. Eggs
used: 6 eggs
Inoculation: shows 25% of bacteria in 1 cm egg box for

Maximum cooking temperature reached inside the tortilla: 60 º C
actual cooking time inside the tortilla: 2 minutes
Decimal Reduction Time Salmonella under these conditions: 0.5 minutes

temperature overnight (12 hours time): 15 º C
specific growth rate at 15 ° C. μ = 0.23 h-1

average temperature during the trip: 28 º C
specific growth rate at 28 ° C. μ = 0.87 h-1

minimum inoculum should be taken to S. enteric infection occurs: 1 million bacteria.


Question: estimate the time that the intake of a spike of the tortilla will cause salmonellosis with 100% certainty.

Note for non-English speaking: 1 skewer tortilla is a quarter (approx.) of it

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