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The z-value is a measure of the change of the D-value with varying temperature, and is a simplified version of an Arrhenius equation and it is equivalent to z=2.303 RT T ref /E. [2] The z-value of an organism in a particular medium is the temperature change required for the D-value to change by a factor of ten, or put another way, the ...
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 .
Benzamide is an organic compound with the chemical formula of C 7 H 7 NO. It is the simplest amide derivative of benzoic acid . In powdered form, it appears as a white solid, while in crystalline form, it appears as colourless crystals. [ 5 ]
A better understanding of the influence of temperature on the properties of foods enables food manufacturers to optimize processing conditions and improve product quality. It is therefore important for food scientists to have analytical techniques to monitor the changes that occur in foods when their temperature varies.
[11] [12] To prevent time-temperature abuse, the amount of time food spends in the danger zone must be minimized. [13] A logarithmic relationship exists between microbial cell death and temperature, that is, a small decrease of cooking temperature can result in considerable numbers of cells surviving the process. [ 14 ]
Thermogravimetric analysis or thermal gravimetric analysis (TGA) is a method of thermal analysis in which the mass of a sample is measured over time as the temperature changes. . This measurement provides information about physical phenomena, such as phase transitions, absorption, adsorption and desorption; as well as chemical phenomena including chemisorptions, thermal decomposition, and ...
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 D 150C = 20 minutes. In the US, the temperature is usually indicated in degrees Fahrenheit ; a notation like D 230 should be understood to mean D 230F (D 110C ).
Benzoic acid is generally not used directly due to its poor water solubility. Concentration as a food preservative is limited by the FDA in the U.S. to 0.1% by weight. [8] Sodium benzoate is also allowed as an animal food additive at up to 0.1%, per the Association of American Feed Control Officials. [9]