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The term F-value or "F Tref/z" is defined as the equivalent number of minutes to a certain reference temperature (T ref) for a certain control microorganism with an established Z-value. [1] Z-value is a term used in microbial thermal death time calculations. It is the number of degrees the temperature has to be increased to achieve a tenfold (i ...
To find a negative value such as –0.83, one could use a cumulative table for negative z-values [3] which yield a probability of 0.20327. But since the normal distribution curve is symmetrical, probabilities for only positive values of Z are typically given.
The Z-factor defines a characteristic parameter of the capability of hit identification for each given assay. The following categorization of HTS assay quality by the value of the Z-Factor is a modification of Table 1 shown in Zhang et al. (1999); [2] note that the Z-factor cannot exceed one.
The D-value at an unknown temperature can be calculated knowing the D-value at a given temperature provided the Z-value is known. The target of reduction in canning is the 12- D reduction of C. botulinum, which means that processing time will reduce the amount of this bacteria by a factor of 10 12 .
About 68% of values drawn from a normal distribution are within one standard deviation σ from the mean; about 95% of the values lie within two standard deviations; and about 99.7% are within three standard deviations. [8] This fact is known as the 68–95–99.7 (empirical) rule, or the 3-sigma rule.
A bar chart is a graph that shows categorical data as bars presenting heights (vertical bar) or widths (horizontal bar) proportional to represent values. Bar charts provide an image that could also be represented in a tabular format. [10] In the bar chart example, we have the birth rate in Brazil for the December months from 2010 to 2016. [9]
A 0.5 McFarland standard is prepared by mixing 0.05 mL of 1.175% barium chloride dihydrate (BaCl 2 •2H 2 O), with 9.95 mL of 1% sulfuric acid (H 2 SO 4). [ 1 ] Now there are McFarland standards prepared from suspensions of latex particles, which lengthens the shelf life and stability of the suspensions.
In microbiology, a colony-forming unit (CFU, cfu or Cfu) is a unit which estimates the number of microbial cells (bacteria, fungi, viruses etc.) in a sample that are viable, able to multiply via binary fission under the controlled conditions. Counting with colony-forming units requires culturing the microbes and counts only viable cells, in ...