Question from a student 20170423a

Question

From: GGGGGG
Sent: Sunday, April 23, 2017 5:23 PM
To: hoishankwan@cuhk.edu.hk
Subject: Question

Can you help me check my answer? 

2014-2015 past paper question B4 (e)

(e)

(i) 

Spores D = 12 

New D value = 2.5/10 = 0.25 

0.25 x 12 = 3 min 

Bacteria D = 13 

New D value = 0.25/15 = 0.0167 

0.0167 x 13 = 0.2171

(ii)

Bacteria 100 ml --> 100D reduction = 10 ^(-98) /ml 

Spores 10/ml --> 10D reduction = 10 ^(-9) / ml 

Bacteria: D = 10

0.0167 x 10 = 0.167 min

Spores : D = 9 

0.25 x 9 = 2.25 min 

Thanks 

Answer: To be answered in review session 2 on 24/4/2017

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