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[14] [1] Some multicellular eukaryotes can also be metabolically active at sub-zero temperatures, such as some conifers; [15] those in the Chironomidae family are still active at −16 °C. [ 16 ] Psychrophilic algae can tolerate cold temperatures, like this Chlamydomonas green algae growing on snow in Antarctica .
At the same time, other studies show that resistance levels in ancient bacteria to modern antibiotics remain lower than in the contemporary bacteria from the active (thawed) layer above them, [1] suggesting that this risk is "no greater" than in any other soil. [17]
Freezing temperatures curb the spoiling effect of microorganisms in food, but can also preserve some pathogens unharmed for long periods of time. Freezing kills some microorganisms by physical trauma, others are sublethally injured by freezing, and may recover to become infectious.
Mesophiles are bacteria that thrive at moderate temperatures, growing best between 20° and 45 °C. These temperatures align with the natural body temperatures of humans, which is why many human pathogens are mesophiles. [15] Thermophiles; Survive under temperatures of 45–80 °C. [16]
Freezing is a phase transition in which a liquid turns into a solid when its temperature is lowered below its freezing point. [ 1 ] [ 2 ] For most substances, the melting and freezing points are the same temperature; however, certain substances possess differing solid-liquid transition temperatures.
Certain bacteria, notably Pseudomonas syringae, are particularly effective at triggering frost formation, raising the nucleation temperature to about −2 °C (28 °F). [13] Bacteria lacking ice nucleation-active proteins (ice-minus bacteria) result in greatly reduced frost damage. [14]
The kinds of bacteria that cause food poisoning do not affect the look, smell, or taste of food. To be safe, FoodSafety.gov's Storage Times chart . 8) Once food has been cooked, all the bacteria ...
A mesophile is an organism that grows best in moderate temperature, neither too hot nor too cold, with an optimum growth range from 20 to 45 °C (68 to 113 °F). [1] The optimum growth temperature for these organisms is 37 °C (about 99 °F). [2]