PDA Technical Glossary

PDA Technical Reports are highly valued membership benefits because they offer expert guidance and opinions on important scientific and regulatory topics and are used as essential references by industry and regulatory authorities around the world. These reports include terms which explain the material and enhance the reader’s understanding.

The database presented here includes the glossary terms from all current technical reports. The database is searchable by keyword, topic, or by technical report. Each definition provided includes a link to the source technical report within the  PDA Technical Report Portal.

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Water Activity (Aw)
Water Activity, Aw is the ratio of the vapor pressure of water in a product (P) to the vapor pressure of water in a product (P) to the vapor pressure of pure water (Po) at the same temperature. It is numerically equal to 1/100 of the RH generated by the product in a closed system. It is a measure of the free or available moisture in the material. Note: Water activity ≠ water content. RH can be calculated from direct measurements partial vapor pressure or dew point, or from indirect measurements by sensors whose physical or electric characteristics are altered by the RH to which they are exposed. Microorganisms need available water within a pharmaceutical product, as well as nutrients and minerals, to proliferate. Water activity, and not water content, is a better measure of the free water, in contrast to bound water that microbial cells require for metabolic activity and osmotic regulation. Effects of reduced Aw on microbial growth include a longer lag phase, slower growth rate, lower numbers of organisms in the stationary phase, and reduced microbial toxin production; below a specified Aw for an organism, microbial growth will not occur. (TR55) (TR67)

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Signal Detection Theory
A means to quantify the ability to discern between signal and noise. According to the theory, there are a number of determiners of how a detecting system will detect a signal, and where its threshold levels will be. The theory can explain how changing the threshold will affect the ability to discern, often exposing how adapted the system is to the task, purpose or goal at which it is aimed. (TR55)

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Slip Sheest
Plastic sheets often made of polyethylene and sometimes used in distribution/transportation warehouse and shipping systems to separate pallet loads of product. Slip sheets may be important due to the ability of polyethylene to concentrate TBA in proximity to product. (TR55)

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Stringer Pallet
A pallet that uses a frame of three or four parallel pieces of lumber (called stringers). The top decks are affixed to the stringers to create the pallet structure. (TR55)

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Stringer
A continuous, longitudinal, solid or notched beam-component of a pallet used to support deck components, often identified by location as the outside or center stringer. (TR55)

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Risk Management
The systematic application of quality management policies, procedures and practices to the tasks of assessing, controlling, communicating and reviewing risk. (TR44) (TR54) (TR54-2) (TR55) (TR67) (TR54-5)

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Risk Assessment
A systematic process of organizing information to support a risk decision to be made within a risk management process. It consists of identification of hazards and the analysis and evaluation of risk associated with exposure to those hazards. (TR30) (TR44) (TR54) (TR58) (TR55) (TR67) (TR57-2) (TR54-5) (TR88)

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Risk Mitigation
Active systematic steps taken to reduce or limit risk. (TR55) (TR67)

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Sensory Characteristic
Olfactory sensation, odor threshold and taste threshold or organohalogen. (TR55)

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Shipping Container
A standardized reusable metal box used for safe, efficient and secure storage and movement of materials and products within a global containerized intermodal freight transport system. Intermodal implies that the container can be moved from one mode of transport to another without unloading and reloading. They are the main type of equipment used in intermodal transport, particularly when one of the modes of transportation is by ship. They can also be referred to as ISO containers because the dimensions have been defined by ISO. Other types of transportation containers can include truck trailers. (TR55)

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Pallets
Pallets are flat transportation structures that are used in the efficient shipping, warehousing and in-plant distribution of goods. A loaded pallet may be moved using a fork lift or pallet jack. They are usually 48 x 40 inches in dimension. They are most commonly constructed of wood but may be plastic, metal or even paper. (TR55)

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Organohalogens
The major organohalogens or organic compounds containing chlorine, bromine or iodine of interest are halophenols and haloanisoles, especially 2,4,6 tricholorophenol (TCP), 2, 4, 6 tribromophenols (TBPs), 2, 4, 6 trichloroanisole (TCA), and 2, 4, 6 tribromoanisole (TBA). (TR55)

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Part per Trillion (ppt)
1 part in 1 x 1012 total parts. Can be measured in mass/mass (e.g., 1 picogram/gram) or in volume/volume (e.g, 1 picoliter/liter). (TR55)

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Part per Billion (ppb)
1 part in 1 x 109 total parts. Can be measured in mass/mass (e.g., 1 nanogram/gram) or in volume/volume (e.g, 1 nanoliter/liter). (TR55)

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Odor Threshold
The lowest concentration of a compound detectable to 50% of the people tested. (TR55)

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Odor Perception
Odors are perceived through stimulation of receptor cells and nerve endings of the trigeminal nerve in the olfactory epithelium, which lie in a small area in the upper reaches of the nasal cavity. Odors are perceived directly through the nose (orthonasal) or during gestation when volatile odorous organaohalogens reach the olfactory centers through the nasopharyneal passage (retonasal). (TR55)

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Moisture Content of Wood
The moisture content of wood is calculated by the following formula: Moisture content = (Mg-Mod)/Mod. Where Mg is the green mass of the wood and Mod is its oven-dry mass (the attainment of constant mass generally after drying in an oven set at 103 ± 2 °C for 24h). The equation can also be expressed as a fraction of the mass of the water and the mass of the oven-dry wood rather than a percentage. For example, 0.59 kg/kg (oven-dry basis) expresses the same moisture content as 59% (oven-dry basis). (TR55)

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LD50/LC50
Median lethal dose or median lethal concentration, of a toxin, radiation, or pathogen is the dose required to kill half the members of a tested population after specified test duration. LD50 figures are frequently used as a general indicator of a substance’s acute toxicity. (TR55)

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Intraperitoneal (i.p.)
Term defines when a chemical is administered through the peritoneal cavity (area that contains the abdominal organs). (TR55)

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Kiln Drying (Wood Pallets)
A process of drying lumber in a dry kiln to a specified moisture content using the correct drying schedule (combination of dry- and wet-bulb temperature settings). Kiln-drying suffices as a heat treatment. This type of treatment is not ISPM certified and would not necessarily have an HT (heat-treated) stamp. However, this is a normal process for drying of lumber. (TR55)

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Hazard Analysis and Critical Control Points (HACCP)
A systematic, proactive, and preventative tool for assuring product quality, reliability, and safety (TR54-3) (TR54) A management system in which potential hazards are addressed through the identification and control of key risk factors (critical control points) of the biological, chemical, and physical hazards from raw material production, procurement and handling, to manufacturing, distribution and consumption of the finished product. (TR55)

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Health Hazard Evaluation (HHE)
A tool for classifying a voluntary recall by a firm. The HHE guides the US FDA in determining the risk to the public from the defective product and appropriate actions for the firm and the FDA to take to protect public health. (TR55)

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Heat-Treated Wood Pallets
Two types of methods to include kiln drying versus steam heat. (TR55)

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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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Good Distribution Practices (GDPs)
Defined as that part of quality assurance that ensures that the quality of the pharmaceutical product is maintained by means of adequate control of numerous activities which occur during the distribution process. (TR55) (commonly abbreviated GDP, or as GDocP to distinguish from “Good Distribution Practice”) Describes standards by which documents are cre­ated and maintained. (TR56)

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FAO (Food and Agriculture Organization)
The FAO’s mandate is to raise levels of nutrition, improve agricultural productivity, better the lives of rural populations, and contribute to the growth of the world economy. (TR55)

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Electronic Nose
An array of electronic sensors designed to selectively identify chemicals responsible for odors. The zNose™ system is one example that is commercially available and consists of a vapor pre-concentrator, a direct-heated high-speed chromatography column, a solid-state sensor and a programmable gate array microprocessor system. (TR55)

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Equilibria Moisture Content of Wood
The moisture content of wood below the fiber saturation point is a function of both the relative humidity and the temperature of surrounding air. The equilibrium moisture content (EMC) is the moisture content at which the wood is neither gaining nor losing moisture; this however, is a dynamic equilibrium and changes with relative humidity and temperature. (TR55)

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Corked or Cork Taint
A musty-moldy off-flavor or taste imparted to the wine primarily due to the presence of 2, Combination Products 6-trichloroanisole (2, Combination Products 6-TCA) produced by the fungalo-methylation of 2, Combination Products 6-tricholorophenol (TCP) associated with corks, wooden barrels, and construction materials in wineries. (TR55)

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Class II Recall
A situation in which use of or exposure to a violative product or may cause temporary or medically reversible adverse health consequences or where the probability of serious adverse health consequence is remote.(TR55)

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Complaint Files
(a) As defined by 21 CFR Part 211.198- Complaint Files. (b) A written record of each complaint shall be maintained in a file designated for drug product complaints. The file regarding such drug product complaints shall be maintained at the establishment where the drug product involved was manufactured, processed, or packed, or such file may be maintained at another facility if the written records in such files are readily available for inspection at that other facility. 1.The written record shall include the following information, where known: the name and strength of the drug product, lot number, name of complainant, nature of complaint, and reply to complainant .2.Where an investigation under 211.192 is conducted, the written record shall include the findings of the investigation and follow-up. The record or copy of the record of the investigation shall be maintained at the establishment where the investigation occurred in accordance with 211.180. (TR55)

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Class I Recall
A situation in which there is a reasonable probability that the use of or exposure to a violative product will cause serious adverse health consequences or death. (TR55)

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Biomethylation
The enzyme chlorophenol o-methyltransferase responsible for fungal methylation has been isolated in cell-free extracts. Biomethylation, in this context, may be seen as a detoxification mechanism, although it plays a role in the production of mycotoxins by secondary metabolism. Slightly xerophilic fungi frequently associated halophenol biomethylation include Trichoderma longibrachiatum, Trichoderma virgatum, Aspergillus sydowii, and Penicillium islandicum. (TR55)

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AOAC International (Association Official Analytical Communities)
Serves communities of the analytical sciences by providing the tools and processes necessary to develop voluntary consensus standards or technical standards through stakeholder consensus and working groups in which the fit-for-purpose and method performance criteria are established and fully documented. (TR55)

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Adverse Event (AE) Report
An AE report is a communication to the U.S. FDA of an undesirable sign or symptom associated with use of a drug as required and detailed by 21 CFR 314.80. These reports are logged into the U.S. FDA’s Adverse Event Reporting System (AERS). Drug manufacturers are required to report adverse event information to FDA. These reports may also may be voluntarily submitted to the FDA directly by healthcare professionals or the general public at Med Watch. The reports are reviewed, safety issues are monitored, and data are periodically analyzed and assessed by the Center for Drug Evaluation and Research (CDER). (TR55)

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