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What is D-value and F value?

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What is D-value and F value?

The z-value of an organism is the temperature, in degrees Fahrenheit, that is required for the thermal destruction curve to move one log cycle. While the D-value gives us the time needed at a certain temperature to kill an organism, the z-value relates the resistance of an organism to differing temperatures.

What is DF and z-value?

The D-value of an organism is the time required in a given medium, at a given temperature, for a ten-fold reduction in the number of organisms. While the D-value gives the time needed at a certain temperature to kill 90% of the organisms, the z-value relates the resistance of an organism to differing temperatures.

What is Fo value in sterilization?

The F0 value tells us the equivalent amount of sterilization (in minutes) that would have been completed had the load been at 250°F. (As temperature increases, so does sterilization/kill rate.)

What is Fo value?

In the sterilization process during pharmaceutical and food manufacturing, the “Fo” value is used as a benchmark for the sterilization time. The Fo value expresses the heating time required for disinfection, and varies according to fluctuations in heat applied to the substance being sterilized.

How is D-value calculated?

The D-value was determined from the inactivation kinetic curve given by the equation: t = D × (log No-log Nf) = D × n [1], where D = D-value (min) at specified conditions, No = bioburden of the chosen bacterium as the BI; Nf = surviving population after an exposure time, t (min), to the selected disinfectant and n = ( …

What is D-value in autoclave?

The D-value is defined as the decimal (or decadal) decay (or reduction) time: i.e. it is the time required, at a specified temperature T, to reduce the microbial population being considered by one logarithmic value, i.e. from 100% to 10% of the initial value.

What are D and Z values?

The D-value gives the time needed at a certain temperature to kill an organism while the Z-value relates the resistance of an organism to differing temperatures. In other words, Z-value is the reciprocal of the slope resulting from the plot of the logarithm of the D-value versus the temperature.

How is Sal value calculated?

To calculate the probability expressed in SAL, double the log reduction number that represents the amount of microbes killed. In other words, a 6-log reduction translates to an SAL of 10-3.

What is Fo value of autoclave?

F0 value is used to determine the exposure time of material for sterilization at a particular temperature. F0 value is the time in minute for the specified temperature that gives the same thermal lethality as at 121 °C in one minute.

What is the unit of D-value?

In the context of thermal analysis it is typical practice to subscript the “D” with an indication of temperature. For example, given a hypothetical organism which is reduced by 90% after exposure to temperatures of 150° C for 20 minutes, the D-value would be written as D150C = 20 minutes.

What is the importance of the F0 value?

F0 value is the time in minute for the specified temperature that gives the same thermal lethality as at 121 °C in one minute. It explains that temperature is not an important factor in thermal sterilization but lethality is important. Time of sterilization can be changed (decrease or increase) according to the lethality of the temperature.

How is the F or p value determined?

The F or P value can be defined as the time or equivalent time taken to reduce initial microbial numbers, at a specified temperature, by a particular value, normally a multiple of the D-value for the target organism.

How is the F 0 value used in sterilization?

F 0 value is used to determine the exposure time of material for sterilization at a particular temperature. F 0 value is the time in minute for the specified temperature that gives the same thermal lethality as at 121 °C in one minute.

How is the F0 value of a material determined?

Some materials are heat sensitive and cannot be sterilized at 121 °C. F0 value is used to determine the exposure time of material for sterilization at a particular temperature. F0 value is the time in minute for the specified temperature that gives the same thermal lethality as at 121 °C in one minute. Related: Determination of Z-Value

Which is the correct value for the F value?

The F value\\**\\ for a process is the number of minutes required to kill a known population of microorganisms in a given food under specified conditions. This F value is usually set at 12 D values to give a theoretical 12 log cycle reduction of the most heat-resistant species of mesophilic spores in a can of food.

When do you use F value in microbiology?

Type in you name, wait 107 seconds, brace yourself. To obtain sterile products, items have to be sterilized. To compare different decontamination processes, in practice a description in terms of minimum exposuretimes F is used.

What is the F value in thermal processing?

The F value** for a process is the number of minutes required to kill a known population of microorganisms in a given food under specified conditions. This F value is usually set at 12 D values to give a theoretical 12 log cycle reduction of the most heat-resistant species of mesophilic spores in a can of food.

How to calculate F0 value, D value and z value?

Calculation of D – Value, Z – Value and F0 – Value for sterilization in autoclave used for microbiology analysis as per USP and BP. F0-Value at a particular temperature other than 121ºC is the time in minutes required to provide the lethality equivalent to that provided at 121ºC for a stated time. (As per USP 2008)