Bacterial Growth and Control

Flashcards covering the mathematical calculation of bacterial populations and the effects of temperature on bacterial growth rate.

Mean division time

The regular interval at which bacteria reproduce, allowing for mathematical predictions of how many bacteria will be present in a given time.

Bacterial growth equation

$$\text{Bacteria at the beginning of the growth period} \times 2^{\text{number of divisions}}$$

Standard form

A method to express large numbers for higher marks, for example writing $262,144$ as $2.62 \times 10^5$ bacteria.

Number of divisions (Calculation)

The number of times bacteria divide over a period, determined by the mean division time (e.g., if bacteria divide every $20$ minutes for $6$ hours, they divide $18$ times).

Industrial fermenters

The note topic following the discussion of bacterial growth and cooling methods.

Exponential growth

The process where the number of bacteria doubles every time they reproduce, resulting in large numbers of cells in short periods.

Refrigerator temperature

Low temperature used to reduce the rate at which bacteria divide, keeping food for longer before it spoils.

Freezing food

A process where bacterial growth stops, though the bacteria are not killed and can resume growth if the temperature increases.

High temperature cooking

The method used to kill bacteria to prevent food spoilage.

Bacteria cell count (Example)

If a population begins with one bacterium and divides $18$ times, the total count is $1 \times 2^{18} = 262,144$ bacteria.