food safety and testing
DESCRIPTION
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. 2. 4. 40 minutes. 8. 1 hour. 16. 1 hour 20 minutes. 32. - PowerPoint PPT PresentationTRANSCRIPT
Food Safety and Testing
Dr Jennifer Newton BSc, MSc, PhDManaging Director
Very, very small...
Bacteria are everywhere!
Binary Fission
Reproduction by Bacteria
Replication
20 minutes
1
2
40 minutes4
1 hour8
1 hour 20 minutes16
6432 1 hour 40 minutes
2 hours
128 2 hour 20 minutes
256 2 hour 40 minutes
3 hours512
3 hours 20 minutes1024
3 hours 40 minutes2048
4 hours4096
4 hours 20 minutes8192
4 hours 40 minutes16384
5 hours32,768
Exponential Growth of Bacteria
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
Above 80C most bacteria die
Room temperature and body temperature most bacteria grow very qickly
Below 0C most bacteriaalso do not multiply
Temperature and Bacteria
Controlling Bacteria’s Growth
Heating to very hot
Freezing
Chilling
Use of chemicals (acid e.g. vinegar, preservatives, salt)
How do we know for certainif 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.