Transcript Industry resource: Express Microbiology presentation

Food Safety and Testing
Dr Jennifer Newton BSc, MSc, PhD
Managing Director
Very, very small...
Bacteria are everywhere!
Reproduction by Bacteria
Replication
Binary Fission
Exponential Growth of Bacteria
1
2
20 minutes
4
40 minutes
8
1 hour
16
1 hour 20 minutes
32
64
1 hour 40 minutes
2 hours
128
2 hour 20 minutes
256
2 hour 40 minutes
512
3 hours
1024
3 hours 20 minutes
2048
3 hours 40 minutes
4096
4 hours
8192
16384
4 hours 20 minutes
4 hours 40 minutes
32,768
5 hours
To put it another way,...
In one day one bacteria will produce
10,000,000,000,000,000,000,000
That would take humans 1,520 years
How do we Keep Food Safe?
• Separation of low – risk from high risk
– High Risk those foods people will eat without
heating (ready to eat)
– Low Risk those foods people usually do not eat
without cooking; e.g. raw meat
•
•
•
•
Good personal hygiene
Cleaning
Pest Control
Proper temperature control
Temperature and Bacteria
Above 80C most
bacteria die
Room temperature
and body temperature
most bacteria grow
very qickly
Below 0C most
bacteria
also do not multiply
Controlling Bacteria’s Growth
Heating to very hot
Freezing
Chilling
Use of chemicals (acid e.g. vinegar,
preservatives, salt)
How do we know for certain
if food is safe to eat?
Have a laboratory test it.
Food with disease causing
bacteria in it tastes and smells
the same as food without it.