What is temperature in microbial growth?

Both extreme cold and hot temperatures require evolutionary adjustments to macromolecules and biological processes. Psychrophiles grow best in the temperature range of 0–15 °C whereas psychrotrophs thrive between 4°C and 25 °C. Mesophiles grow best at moderate temperatures in the range of 20 °C to about 45 °C.

How can high and low temperatures affect the growth of microorganisms?

In general, the higher the temperature, the more easily microorganisms can grow up to a certain point. Very high and very low temperatures both obstruct the enzyme processes microorganisms depend on to survive, but individual species of microorganisms have grown to prefer different levels of temperature.

How does low temperature affect bacterial growth?

EFFECT OF LOW TEMPERATURE ON BACTERIAL GROWTH: Low temperature can influence the response of a microorganism either directly or indirectly. Direct effects include decreased growth rate, enzyme activities, alteration of cell composition and differential nutritional requirements.

How does temperature affect microbial physiology?

How does temperature affect microbial physiology? Slightly increased temperature speeds up the action of enzymes, thus increasing microbial metabolism.

What temperature do microbes like?

Bacteria grow most rapidly in the range of temperatures between 40 °F and 140 °F, doubling in number in as little as 20 minutes. This range of temperatures is often called the “Danger Zone.” To learn more about the “Danger Zone” visit the Food Safety and Inspection Service fact sheet titled Danger Zone.

Does bacteria grow in cold temperatures?

Spoilage bacteria can grow at cold temperatures, such as in the refrigerator. Eventually they cause food to develop off or bad tastes and smells. However, some bacteria such as Listeria monocytogenes (Lm) thrive at cold temperatures, and if present, will grow in the refrigerator and could cause illness.

What is the effect of heat on a population of bacteria?

High temperatures have profound effects on the structural and physiological properties of sporulating and non-sporulating bacteria, with membranes, RNA, DNA, ribosomes, protein and enzymes all affected. Nevertheless, it is apparent that no one single event is responsible for cell death.

How does pH affect microbes?

Microbes, such as bacteria are sensitive to the hydrogen ion concentration they find in their environment. Large proteins, such as enzymes, are affected by pH. Their shape changes (they denature) and the very often brings about an alteration of the ionic charges on the molecule.

How does temperature affect cell growth?

As the temperature increases, molecules move faster, enzymes speed up metabolism and cells rapidly increase in size. But, above a certain value all of these activities are proceeding at such high rates, enzymes start to denature, and the total effect is detrimental. Cellular growth ceases.