The difference between bacterial count of UHT milk and pasteurised milk?

UHT milk (ultra-high temperature milk) is heated to a much higher temperature than pasteurised milk, which results in a longer shelf life and a lower bacterial count.

Pasteurised milk is heated to a temperature of 72°C (161°F) for 15 seconds, which is enough to kill most harmful bacteria, including Salmonella and E. coli. However, some heat-resistant bacteria, such as Bacillus cereus, may survive the pasteurisation process.

UHT milk is heated to a temperature of 135°C (275°F) for 2 seconds, which is enough to kill all bacteria, including heat-resistant bacteria. This means that UHT milk has a much longer shelf life than pasteurised milk, and it does not need to be refrigerated.

The bacterial count of UHT milk is typically less than 1 colony forming unit (CFU) per milliliter, while the bacterial count of pasteurised milk can be as high as 100 CFU per milliliter. This means that UHT milk is much less likely to cause foodborne illness than pasteurised milk.

Here is a table summarising the key differences between UHT milk and pasteurised milk:

| Feature | UHT milk | Pasteurised milk |

|---|---|---|

| Temperature | 135°C (275°F) for 2 seconds | 72°C (161°F) for 15 seconds |

| Shelf life | Up to 6 months at room temperature | Up to 1 week in the refrigerator |

| Bacterial count | Less than 1 CFU per milliliter | Up to 100 CFU per milliliter |

| Risk of foodborne illness | Very low | Low |