M1L4 - Microbial control

Autoclave

This uses moist heat to cause denaturing and coagulation of vital proteins

Decimal reduction time

This is the length of time taken to obtain a 10-fold reduction in bacterial count

Boiling

This uses moist heat to kill microbes, undertaken at 100C for 15 minutes

Batch pasteurisation

This is undertaken at 63C for 30 minutes

Flash pasteurisation

This is undertaken at 71C for 15 seconds

UHT processing

This is undertaken at 140C for at least one second

Dry heat

This causes oxidation of vital proteins inside bacteria to kill them

Hot air oven

This is undertaken at 160C for 2 hours, used to sterilise glassware

Incineration

This is undertaken at temperatures above 1000C and is used to sterilise waste products

Freezing

This uses temperatures below 0C to control microbial growth

Filtration

This uses a membrane with pores too small for microorganisms to pass through

Depth filter

This is an ~8mm thick filter made of fibres or asbestos, used to remove large dirt particles

Membrane filter

This is a thin filter made of cellulose acetate/nitrate, with differing sized pores and small dirt carrying capacity

Nucleation track filter

This uses very small very distinct pores to prepare samples for electron microscopy

Non-IR irradiation

This involves UV causing damage to DNA in cells by catalysing the formation of pyrimidine dimers or causing direct protein damage

Nucleotide excision repair

This involves the endonuclease enzyme removing damaged nucleotides, DNA pol. 1 replacing them, and ligase joining the repaired strand together

Direct repair

This involves the photoreactivation via light and photolyase to repair damaged nucleotides

Recombinational repair

This involves the repairing of damaged nucleotides with RecA

SOS

This is a large cascade process used to repair large swaths of damaged DNA, very error prone

Gamma irradiation

This method of irradiation kills bacteria directly by catalysing the formation of free radicals