Glossary Terms (Simple List)
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Fumigation of Wood Pallets
The currently approved International Standards for Phytosanitary Measures (ISPM) fumigation method is methyl bromide (MB) fumigation and is one of the two approved phytosanitary measures in ISPM 15 (treatment and marking of wood packaging materials [WPM] that is required for international shipment. The use of methyl bromide is not permitted in some IPPC countries (e.g. the EU), and the latest ISPM 15 standard has a recommendation to reduce its use. Note: Steam heat treatment is the other ISPM 15 approved method. (TR55)
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F-Value (Lethality Factor)
A measurement of sterilization effectiveness, the F-value is the calculated equivalent lethality (using a specified z-value), in terms of minutes at a reference temperature (Tref), delivered by a sterilization cycle. (TR1) (TR3) (TR30) (TR48) (TR61)
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F-Value (Lethality Factor) -- FBiological
A term used to describe the delivered lethality, measured in terms of actual kill of microorganisms on or in a BI challenge system. The FBiological-value is calculated as DT × LR, where DT is the D-value of the BI system at the reference temperature (T) and LR is the actual logarithmic reduction (log N0 – log NF) of the BI population achieved during the cycle. (TR1)
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F-Value (Lethality Factor) -- FO
A term used when the specific reference conditions of Tref = 121.1°C and z = 10°C are used to calculate the equivalent lethality. For example, when the z-value of the BI is 10°C a cycle with an F(T=121.1°C, z=10°C), or F0, equal to 8 minutes is equivalent (in terms of delivered lethality) to a square wave cycle of 8 minutes at 121.1°C. A square wave cycle that provided an exposure of 25.9 minutes at 160deg;C would also yield an F0 of 8 minutes. (TR1)
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F-Value (Lethality Factor) -- Fphysical
A term used to describe the delivered lethality calculated based on the physical parameters of the cycle. The FPhysical-value is the integration of the lethal rate (L) over time. The lethal rate is calculated for a reference temperature (Tref-) and z-value using the equation: L = 10(T-Tref- )/z. (TR1)
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F-Value (Lethality Factor) -- F-Value for Depyrogenation
The term F-value may also be used in dryheat depyrogenation processes to calculate the time in minutes equivalent to a lethality or endotoxin destruction effect delivered by dry heat at 250°C. The F-value reference temperature is set at 250°C and the z-value minimum is set at 46.4°C. (TR3)
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F-Value (Lethality Factor)-- FH
A term used when the specific reference conditions of Tref = 160°C and z=20°C are used to calculate the equivalent lethality. For example, when the z-value of the BI is 20°C a process with an F(T=160°C, z=20°C), or FH, equal to 8 minutes is equivalent (in terms of delivered lethality) to a square wave process of 8 minutes at 160°C. A square wave process that provided an exposure of 45.2 minutes at 145°C would also yield an FH of 8 minutes. (TR3)
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Gamma Irradiation
The process by which a material is rendered sterile by exposing the material to a radioactive source, such as Cobalt 60. (TR70)
Ionizing radiation that can be used to sterilize a material. (TR26)
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Gauge Pressure
The pressure measured by a pressure gauge. Typically expressed in units of psig, bar or kilopascal. (TR45)
Gauge pressure is the difference between a given fluid pressure and that of the atmosphere. (TR26)
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Gels
Gels (sometimes called jellies) are semisolid systems consisting either of suspensions of small inorganic particles or of organic molecules interpenetrated by a liquid. Gels can be classed either as single-phase or two-phase systems. (TR79)