Explore the question in detail with explanation, related questions, and community discussions.
Bacteria are microscopic living organisms that thrive in a variety of environments. While some bacteria are harmless or even beneficial (such as those found in the gut or used in yogurt production), others are harmful and can cause food poisoning, infections, or other diseases. One of the most effective ways to control harmful bacteria is by using heat, since high temperatures disrupt bacterial proteins and enzymes, causing the cells to die.
The critical temperature at which most bacteria are killed is 149°F (65°C). At this temperature, the bacterial cell proteins denature (lose their structure), and the cell cannot survive. This principle is the basis of several food safety and sterilization techniques:
Cooking food: Cooking meat, poultry, and seafood above 65°C ensures harmful bacteria such as Salmonella, E. coli, and Listeria are destroyed.
Pasteurization: Milk and juices are heated to around 63–72°C to kill pathogenic bacteria without spoiling the food.
Sterilization: Medical equipment is exposed to even higher temperatures (above 120°C in autoclaves) to eliminate all bacteria, viruses, and spores.
It’s important to note that bacteria are not instantly killed at 149°F; instead, the duration of heating also plays a role. For example, holding food at this temperature for several minutes ensures bacterial destruction.
On the other hand, at lower temperatures such as 102°F (39°C) or 106°F (41°C), bacteria do not die — they often thrive, since this is close to the optimal growth range for many microbes. This explains why fevers in humans (about 102–104°F) can slow bacterial growth but do not completely eliminate bacteria.
Therefore, the correct answer is 149°F, as it is the standard threshold at which most harmful bacteria are destroyed, making heat treatment a vital part of everyday science, health, and food safety.
Discussion
Leave a Comment