What are the 5 conditons conducive for rapid bacterial growth?

Bacteria grow in very diverse conditions, which explains why they are found nearly everywhere on Earth. Although bacteria are good at adapting to their environments, certain conditions promote bacterial growth more than others. These conditions include temperature, moisture, pH and environmental oxygen. Understanding the optimal conditions for bacterial growth can potentially help you reduce your risk for bacterial infections and food poisoning.

Most disease-causing bacteria thrive in warm temperatures, especially those close to body temperature. The human body, therefore, provides an ideal environment for many types of bacteria to grow. Certain strains of bacteria, however, can grow at lower or higher temperatures. Since ideal temperature is crucial for the growth of any given species of bacteria, food must be handled appropriately to avoid food poisoning. In most cases -- but not all -- refrigerating or freezing food is sufficient to suppress the growth disease-causing bacteria, such as Staphylococcus. Thoroughly cooking meats and poultry to the correct internal temperature is also important to kill harmful bacteria that may be present in the food, such as Salmonella and E. coli.

Moisture content Microorganisms need water in an available form to grow in food products. The control of the moisture content in foods is one of the oldest exploited preservation strategies. Food microbiologists generally describe the water requirements of microorganisms in terms of the water activity (aw) of the food or environment. Water activity is defined as the ratio of water vapor pressure of the food substrate to the vapor pressure of pure water at the same temperature .

pH and acidity Increasing the acidity of foods, either through fermentation or the addition of weak acids, has been used as a preservation method since ancient times. In their natural state, most foods such as meat, fish, and vegetables are slightly acidic while most fruits are moderately acidic. A few foods such as egg white are alkaline. 

Nutrient content Microorganisms require certain basic nutrients for growth and maintenance of metabolic functions. The amount and type of nutrients required range widely depending on the microorganism. These nutrients include water, a source of energy, nitrogen, vitamins, and minerals .

Biological structure Plant and animal derived foods, especially in the raw state, have biological structures that may prevent the entry and growth of pathogenic microorganisms. Examples of such physical barriers include testa of seeds, skin of fruits and vegetables, shell of nuts, animal hide, egg cuticle, shell, and membranes.

Redox potential The oxidation-reduction or redox potential of a substance is defined in terms of the ratio of the total oxidizing (electron accepting) power to the total reducing (electron donating) power of the substance. In effect, redox potential is a measurement of the ease by which a substance gains or loses electrons. The redox potential (Eh) is measured in terms of millivolts. A fully oxidized standard oxygen electrode will have an Eh of +810 mV at pH 7.0, 30 °C (86 °F), and under the same conditions, a completely reduced standard hydrogen electrode will have an Eh of -420 mV. The Eh is dependent on the pH of the substrate; normally the Eh is taken at pH 7.0 .