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.