|
|
| (190 intermediate revisions by the same user not shown) |
| Line 1: |
Line 1: |
| [[File:Tomato laboratory research.jpg|right|200px]] | | <div class="nonumtoc">__TOC__</div> |
| '''Title''': ''What is the importance of a food and beverage testing laboratory to society?''
| | {{ombox |
| | | type = notice |
| | | style = width: 960px; |
| | | text = This is sublevel5 of my sandbox, where I play with features and test MediaWiki code. If you wish to leave a comment for me, please see [[User_talk:Shawndouglas|my discussion page]] instead.<p></p> |
| | }} |
|
| |
|
| '''Author for citation''': Shawn E. Douglas
| | ==Sandbox begins below== |
| | | {{raw:wikipedia::Detection limit}} |
| '''License for content''': [https://creativecommons.org/licenses/by-sa/4.0/ Creative Commons Attribution-ShareAlike 4.0 International]
| |
| | |
| '''Publication date''': August 2022
| |
| | |
| ==Introduction== | |
| Humanity's focus on food and water security remains one of its most important tasks in the twenty-first century,<ref name="NizaRibieroFood22">{{Citation |last=Niza-Ribeiro |first=João |date=2022 |title=Food and water security and safety for an ever-expanding human population |url=https://linkinghub.elsevier.com/retrieve/pii/B9780128227947000034 |work=One Health |language=en |publisher=Elsevier |pages=155–204 |doi=10.1016/b978-0-12-822794-7.00003-4 |isbn=978-0-12-822794-7 |accessdate=2022-08-10}}</ref><ref>{{Cite journal |last=Young |first=Sera L |last2=Frongillo |first2=Edward A |last3=Jamaluddine |first3=Zeina |last4=Melgar-Quiñonez |first4=Hugo |last5=Pérez-Escamilla |first5=Rafael |last6=Ringler |first6=Claudia |last7=Rosinger |first7=Asher Y |date=2021-07-30 |title=Perspective: The Importance of Water Security for Ensuring Food Security, Good Nutrition, and Well-being |url=https://academic.oup.com/advances/article/12/4/1058/6144691 |journal=Advances in Nutrition |language=en |volume=12 |issue=4 |pages=1058–1073 |doi=10.1093/advances/nmab003 |issn=2161-8313 |pmc=PMC8321834 |pmid=33601407}}</ref><ref>{{Cite journal |last=Hameed |first=Maysoun |last2=Moradkhani |first2=Hamid |last3=Ahmadalipour |first3=Ali |last4=Moftakhari |first4=Hamed |last5=Abbaszadeh |first5=Peyman |last6=Alipour |first6=Atieh |date=2019-04-02 |title=A Review of the 21st Century Challenges in the Food-Energy-Water Security in the Middle East |url=https://www.mdpi.com/2073-4441/11/4/682 |journal=Water |language=en |volume=11 |issue=4 |pages=682 |doi=10.3390/w11040682 |issn=2073-4441}}</ref> particularly in the face of growing concerns about the negative ramifications of climate change.<ref>{{Cite journal |last=Molotoks |first=Amy |last2=Smith |first2=Pete |last3=Dawson |first3=Terence P. |date=2021-02 |title=Impacts of land use, population, and climate change on global food security |url=https://onlinelibrary.wiley.com/doi/10.1002/fes3.261 |journal=Food and Energy Security |language=en |volume=10 |issue=1 |doi=10.1002/fes3.261 |issn=2048-3694}}</ref><ref>{{Citation |last=Din |first=Muhammad Sami Ul |last2=Mubeen |first2=Muhammad |last3=Hussain |first3=Sajjad |last4=Ahmad |first4=Ashfaq |last5=Hussain |first5=Nazim |last6=Ali |first6=Muhammad Anjum |last7=El Sabagh |first7=Ayman |last8=Elsabagh |first8=Mabrouk |last9=Shah |first9=Ghulam Mustafa |date=2022 |editor-last=Jatoi |editor-first=Wajid Nasim |editor2-last=Mubeen |editor2-first=Muhammad |editor3-last=Ahmad |editor3-first=Ashfaq |editor4-last=Cheema |editor4-first=Mumtaz Akhtar |editor5-last=Lin |editor5-first=Zhaohui |title=World Nations Priorities on Climate Change and Food Security |url=https://link.springer.com/10.1007/978-3-030-79408-8_22 |work=Building Climate Resilience in Agriculture |language=en |publisher=Springer International Publishing |place=Cham |pages=365–384 |doi=10.1007/978-3-030-79408-8_22 |isbn=978-3-030-79407-1 |accessdate=2022-08-10}}</ref> Without a continued focus on food and water security—including all the quality and safety assurances that come with it—many elements of the world population face a grim reality of insufficient food, limited access to clean water, and malnutrition.<ref name="NizaRibieroFood22" /><ref>{{Cite journal |last=Miller |first=Joshua D |last2=Workman |first2=Cassandra L |last3=Panchang |first3=Sarita V |last4=Sneegas |first4=Gretchen |last5=Adams |first5=Ellis A |last6=Young |first6=Sera L |last7=Thompson |first7=Amanda L |date=2021-12-01 |title=Water Security and Nutrition: Current Knowledge and Research Opportunities |url=https://academic.oup.com/advances/article/12/6/2525/6322255 |journal=Advances in Nutrition |language=en |volume=12 |issue=6 |pages=2525–2539 |doi=10.1093/advances/nmab075 |issn=2161-8313 |pmc=PMC8634318 |pmid=34265039}}</ref>
| |
| | |
| In contrast to these stark realities (which are just as much about agricultural practices, societal and governmental practices, public health practices, and human approaches to climate change), much has admittedly improved in the way we ensure food and beverage security and safety, at least compared to times prior to the twentieth century. In fact, the laboratory and the science practiced in it have arguably played a significant role in better ensuring safe, quality food and beverages in our lives. However, the laboratory is only one part of an otherwise "complex adaptive system of governance"<ref name="LyttonAnIntro19">{{Cite book |last=Lytton |first=Timothy D. |date=2019 |chapter=An Introduction to the Food Safety System |title=Outbreak: Foodborne Illness and the Struggle for Food Safety |publisher=The University of Chicago Press |place=Chicago ; London |pages=1-23 |isbn=978-0-226-61154-9}}</ref> that is food safety, which in turn is only one part of a larger system dedicated to food and water security.
| |
| | |
| This brief topical article will examine how modern society benefits from a food and beverage testing laboratory. It will turn to history, statistical data, and description of the roles such labs play, demonstrating their overall value.
| |
| | |
| ==History of food and beverage testing and regulation==
| |
| The history of laboratory-based food and beverage tasting is a scattered one, with little being documented about foodborne illness and food safety until the nineteenth century. With a better understanding of bacteria and their relationship to disease, however, more was being said about the topic by the mid- to late-1800s.<ref name="RobertsTheFood01">{{Cite book |last=Roberts |first=Cynthia A. |date=2001 |title=The food safety information handbook |pages=25-28 |publisher=Oryx Press |place=Westport, CT |isbn=978-1-57356-305-5}}</ref> In the Northwest United States during the 1860s, recognition was growing about the threat that tainted milk originating from dairy cows being singularly fed distillery byproducts had to human health. Not only was the milk generated from such cows thin and low in nutrients, but it also was adulterated with questionable substances to give it a better appearance. This resulted in many children and adults dying from consuming the product. The efforts of Dr. Henry Coit and others in the late 1800s to develop a certification program for milk, which included laboratory testing among other activities, eventually helped plant the seeds for a national food safety program.<ref>{{Cite book |last=Lytton |first=Timothy D. |date=2019 |title=Outbreak: foodborne illness and the struggle for food safety |chapter=Chapter 2: The Gospel of Clean Milk |publisher=The University of Chicago Press |place=Chicago ; London |pages=24-64 |isbn=978-0-226-61154-9}}</ref>
| |
| | |
| Roughly around the same time, during the 1880s, Britain saw more public health awareness develop in regards to digestive bacterial infections. "As deadlier infections retreated," argues social historian Anne Hardy, "food poisoning became an increasing concern of local and national health authorities, who sought both to raise public awareness of the condition as illness, and to regulate and improve food handling practices."<ref name="HardyFood99">{{Cite journal |last=Hardy |first=A. |date=1999-08-01 |title=Food, Hygiene, and the Laboratory. A Short History of Food Poisoning in Britain, circa 1850-1950 |url=https://academic.oup.com/shm/article-lookup/doi/10.1093/shm/12.2.293 |journal=Social History of Medicine |language=en |volume=12 |issue=2 |pages=293–311 |doi=10.1093/shm/12.2.293 |issn=0951-631X}}</ref> This led to further efforts from public health laboratories to promote the reporting and tracking of food poisoning cases by the 1940s.<ref name="HardyFood99" />
| |
| | |
| With the recognition of bacterial and other forms of contamination of foodstuffs, as well as the effects of dangerous adulterations with toxic substances, additional progress was made in the realm of regulating and testing produced food and beverages. Notes of interest along the way include<ref name=":0">{{Cite book |last=Redman |first=Nina |date=2007 |title=Food safety: a reference handbook |url=https://www.worldcat.org/title/mediawiki/oclc/ocm83609690 |chapter=Chapter 1: Background and History |series=Contemporary world issues |edition=2nd ed |publisher=ABC-CLIO |place=Santa Barbara, Calif |isbn=978-1-59884-048-3 |oclc=ocm83609690}}</ref><ref name=":1">{{Cite book |last=Stevens, K.; Hood, S. |date=2019 |editor-last=Doyle |editor-first=Michael P. |editor2-last=Diez-Gonzalez |editor2-first=Francisco |editor3-last=Hill |editor3-first=Colin |title=Food microbiology: fundamentals and frontiers |chapter=Chapter 40. Food Safety Management Systems |edition=5th edition |publisher=ASM Press |place=Washington, DC |pages=1007-20 |isbn=978-1-55581-997-2}}</ref><ref>{{Cite book |last=Detwiler |first=Darin S. |date=2020 |title=Food safety: past, present, and predictions |chapter=Chapter 2: "Modernization" started over a century ago |publisher=Academic Press |place=London [England] ; San Diego, CA |pages=11-23 |isbn=978-0-12-818219-2}}</ref><ref name="FDABackFSMA18">{{cite web |url=https://www.fda.gov/food/food-safety-modernization-act-fsma/background-fda-food-safety-modernization-act-fsma |title=Background on the FDA Food Safety Modernization Act (FSMA) |publisher=Food and Drug Administration |date=30 January 2018 |accessdate=14 August 2022}}</ref><ref name="DouglasFDA22">{{cite web |url=https://www.limswiki.org/index.php/LII:FDA_Food_Safety_Modernization_Act_Final_Rule_on_Laboratory_Accreditation_for_Analyses_of_Foods:_Considerations_for_Labs_and_Informatics_Vendors |title=FDA Food Safety Modernization Act Final Rule on Laboratory Accreditation for Analyses of Foods: Considerations for Labs and Informatics Vendors |author=Douglas, S. |work=LIMSwiki.org |date=21 February 2022 |accessdate=14 August 2022}}</ref>:
| |
| | |
| *The Pure Food and Drug Act and Beef Inspection Act were passed in 1906 in response to food quality issues in packing plants, on farms, and other areas of food production.
| |
| *In 1927, the U.S. Food, Drug, and Insecticide Administration was formed to better enforce the Pure Food Act.
| |
| *By 1945, ''Clostridium perfringens'' was being identified as a common cause of foodborne illness<ref name="RobertsTheFood01" />, and today it is recognized by the [[Centers for Disease Control and Prevention]] (CDC) as one of the top five provocateurs of foodborne illness.<ref name="CDCFood20">{{cite web |url=https://www.cdc.gov/foodsafety/foodborne-germs.html |title=Foodborne Germs and Illnesses |publisher=Centers for Disease Control and Prevention |date=18 March 2020 |accessdate=13 August 2022}}</ref>
| |
| *The seeds of the Hazard Analysis and Critical Control Points (HACCP) quality control method were planted in 1959, when Pillsbury began working with NASA to ensure safe foods for astronauts. The value of Pillsbury and NASA's methodology became apparent to the food and beverage industry by 1972, and other organizations began adopting HACCP for food safety.
| |
| *The Fair Packaging and Labeling Act of 1966 brought standardized, more accurate labeling to food and beverages.
| |
| *The Food Quality Protection Act of 1996 mandated HACCP for most food processors and improved pesticide level calculations.
| |
| *FDA Food Safety Modernization Act (FSMA) was enacted in 2011, giving the FDA more enforcement authority and tools to improve the backbone of the U.S. food and water supply.
| |
| *In December 2021, the Laboratory Accreditation for Analyses of Foods (LAAF) amendment to the FSMA was approved, providing for an accreditation program for laboratories wanting to further participate in the critical role of ensuring the safety of the U.S. food supply through the "testing of food in certain circumstances."
| |
| | |
| This progression of scientific discovery and regulatory action has surely managed to reduce risks to U.S. food and beverage consumers, though not without complication and complexity.<ref name="LyttonAnIntro19" /><ref>{{Cite journal |last=Floros |first=John D. |last2=Newsome |first2=Rosetta |last3=Fisher |first3=William |last4=Barbosa-Cánovas |first4=Gustavo V. |last5=Chen |first5=Hongda |last6=Dunne |first6=C. Patrick |last7=German |first7=J. Bruce |last8=Hall |first8=Richard L. |last9=Heldman |first9=Dennis R. |last10=Karwe |first10=Mukund V. |last11=Knabel |first11=Stephen J. |date=2010-08-26 |title=Feeding the World Today and Tomorrow: The Importance of Food Science and Technology: An IFT Scientific Review |url=https://onlinelibrary.wiley.com/doi/10.1111/j.1541-4337.2010.00127.x |journal=Comprehensive Reviews in Food Science and Food Safety |language=en |volume=9 |issue=5 |pages=572–599 |doi=10.1111/j.1541-4337.2010.00127.x}}</ref> As the U.S. population has grown over the past 100 years, it has become more difficult to have a sufficient number of inspectors to examine every facility and all they do, necessitating a risk assessment approach to food and beverage safety.<ref name=":0" /><ref name=":1" /><ref>{{Cite book |date=1998 |title=Food Safety: Current Status and Future Needs |url=http://www.ncbi.nlm.nih.gov/books/NBK562616/ |series=American Academy of Microbiology Colloquia Reports |publisher=American Society for Microbiology |place=Washington (DC) |pmid=33001600}}</ref> As such, the laboratory is a critical component of risk-based safety assessments of food and beverage products.
| |
| | |
| ==Related statistics==
| |
| | |
| Estimates of Foodborne Illness in the United States - "All told, contaminated food causes 48 million illnesses, 128,000 hospitalizations, and 3,000 deaths each year in the United States."<span> </span>: https://www.cdc.gov/foodborneburden/index.html
| |
| | |
| Laboratory utilization statistics (2013): https://www.foodsafetynews.com/2013/10/food-labs-integral-to-changing-world-of-food-safety/
| |
| | |
| ==The roles a laboratory may have in the food and beverage industry==
| |
| Laboratories directly and tangentially related to the food and beverage industry play a number of roles, depending on where they're situated. These roles prove to be important in the greater scheme of industry activities, in turn providing a number of benefits to society. As gleaned from prior discussion, as well as other sources, these laboratory roles can be broadly broken into three categories: research and development (R&D), pre-manufacturing and manufacturing, and post-production regulation and security.
| |
| | |
| ===R&D roles===
| |
| The laboratory participating in these roles is performing one or more tasks that relate to the development or improvement of a food, beverage, additive, or spice. This often leads to a commercial formulation, which has the "necessary details required to scale and produce your [food or beverage] in a consistent, efficient, and safe manner."<ref name="BSCommForm">{{cite web |url=https://www.bevsource.com/news/why-you-need-commercial-formula |title=Why You Need A Commercial Formula |publisher=BevSource |date=13 August 2022}}</ref> Even packaging solutions are targets for R&D labs in the food and beverage industry.<ref name="GudeSol19">{{cite book |chapter=Solutions Commonly Applied in Industry and Outsourced to Expert Laboratories |title=Food Contact Materials Analysis: Mass Spectrometry Techniques |author=Gude, T. |editor=Suman, M. |publisher=Royal Society of Chemistry |doi=10.1039/9781788012973-00245 |isbn=9781788017190 |year=2019}}</ref>
| |
| | |
| The R&D lab is typically placed outside the manufacturing context proper, but not necessarily always. Some manufacturing companies may have an entire research complex dedicated to creating and improving some aspect of their products.<ref name="MonBreak16">{{cite web |url=https://ir.mondelezinternational.com/news-releases/news-release-details/mondelez-international-breaks-ground-new-research-development |title=Mondelez International Breaks Ground for New Research & Development Center in Poland |publisher=Mondelez International |date=08 June 2016 |accessdate=13 August 2022}}</ref> Other companies may take their R&D to a third-party lab dedicated to conducting development and formulation activities for manufacturers.<ref name="BSCommForm" /><ref name="GudeSol19" /> Food and beverage research activities aren't confined to manufacturers, however. Some higher education institutions, such as the Hartwick College Center for Craft Food & Beverage, provide research and development opportunities to students engaging in work-study programs, often in partnership with some other commercial enterprise.<ref name="HartFoodBev">{{cite web |url=https://www.hartwick.edu/about-us/center-for-craft-food-and-beverage/ |title=Hartwick College Center for Craft Food & Beverage |publisher=Hartwick College |accessdate=13 August 2022}}</ref>
| |
| | |
| Food and beverage R&D labs may work towards improving packaging, testing a product's shelf life (i.e., stability), conducting flavor or aroma analysis, developing and innovating foodstuffs, reformulating existing products, and researching genetic modifications to ingredients. The end user benefits by having fresher foods that are culinarily pleasing, more nutritious, and safer for consumption.
| |
| | |
| ===Pre-manufacturing and manufacturing roles===
| |
| The laboratory participating in these roles is performing one or more tasks that relate to the preparative (i.e., pre-manufacturing) or quality control (i.e., manufacturing) tasks of food and beverage production. Preparative work such as caloric and nutritional analysis may happen in a variety of contexts, from inside the R&D lab to in the manufacturing facility's lab itself, if it has one. This work may also be conducted by a third-party lab, or it may even be performed using non-laboratory techniques such as food composition database analysis.<ref name="ESHAHow14">{{cite web |url=https://esha.com/wp-content/uploads/2014/12/ESHA-Obtaining-Nutritional-Analysis-eBook.pdf |format=PDF |title=How to Obtain a Nutritional Analysis of Your Food Product |publisher=ESHA Research |date=December 2014 |accessdate=13 August 2022}}</ref><ref name="NohRecent20">{{cite journal |title=Recent Techniques in Nutrient Analysis for Food Composition Database |journal=Molecules |author=Noh, M.F.M.; Gunasegavan, R.D.-N.; Khalid, N.M. et al. |volume=25 |issue=19 |at=4567 |year=2020 |doi=10.3390/molecules25194567 |pmid=33036314 |pmc=PMC7582643}}</ref> However, caloric and nutritional testing—in conjunction with meeting regulatory-driven labeling requirements—still lands firmly in the role of pre-manufacturing activity, definitively after commercial formulation and packing requirements have been finalized but before the formal manufacturing process has begun.<ref name="BSNutTest">{{cite web |url=https://www.bevsource.com/news/what-do-i-need-know-about-nutrition-testing-my-beverage-brand |title=What Do I Need To Know About Nutrition Testing for My Beverage Brand? |publisher=BevSource |date=13 August 2022 }}</ref> Allergen testing works in a vaguely similar fashion, though the manufacturer ideally uses a full set of best practices for food allergen management and testing that is confirming allergens (and correct labeling) from ingredient ordering to final production line cleanup (e.g., when a new allergen-free commercial formulation is being made or an unintended contamination has occurred).<ref name="CA80-2020">{{cite web |url=https://www.fao.org/fao-who-codexalimentarius/sh-proxy/en/?lnk=1&url=https%253A%252F%252Fworkspace.fao.org%252Fsites%252Fcodex%252FStandards%252FCXC%2B80-2020%252FCXC_080e.pdf |format=PDF |title=Code of Practice on Food Allergen Management for Food Business Operators, CXC 80-2020 |work=Codex Alimentarius |date=2020 |accessdate=13 August 2022}}</ref> The end user benefits from these caloric, nutritional, and allergen analysis activities not only through the provision of a more transparent window into what they are consuming, but these laboratory activities also can better ensure end users' attempts at maintaining their own good health.
| |
| | |
| Finally, laboratory testing can also be found along the production chain in the manufacturing facility itself. This type of testing is couched as [[quality control]] testing, primarily, or as [[quality assurance]], secondarily. Some of this analysis may be integrated into the production workflow, as with x-ray inspection.<ref name="DrausQual17">{{cite web |url=https://www.eaglepi.com/blog/quality-control-or-quality-assurance-in-the-food-industry/ |title=Quality Control or Quality Assurance in the Food Industry?: X-ray Inspection Equipment Ensures Both |author=Draus, C. |work=Eagle PI |date=15 November 2017 |accessdate=13 August 2022}}</ref> Fluorescence sensing technologies are also useful for contaminant testing, though they are largely limited to laboratory use, with hopes they may become more relevant for inspection at the point of production.<ref name="HanPersp20">{{cite journal |title=Perspective on recent developments of nanomaterial based fluorescent sensors: applications in safety and quality control of food and beverages |journal=Journal of Food and Drug Analysis |author=Han, A.; Hao, S.; Yang, Y. et al. |volume=28 |issue=4 |at=2 |year=2020 |doi=10.38212/2224-6614.1270}}</ref> This move to "novel, rapid, and non-destructive" methods of testing both in the lab and in the production facility appears to be a growing trend<ref name="">{{cite book |chapter=Chapter 1. Quality Control in Beverage Production: An Overview |title=Quality Control in the Beverage Industry |series=The Science of Beverages |volume=17 |editor=Grumezescu, A.M.; Holban, A.M. |author=Aadil, R.M.; Madni, G.M.; Roobab, U. et al. |publisher=Elsevier |pages=1-38 |isbn=9780128166826}}</ref>
| |
| , loosening the concept of the "quality control laboratory" as an entity in the facility. Regardless of analytical location, the quality control lab provides benefits to society by being a critical component of an overall [[quality management system]] that better ensures the safety of those consuming the final product.
| |
| | |
| ===Post-production regulation and security roles===
| |
| The laboratory participating in these roles is performing one or more tasks that relate to the post-production examination of foods and beverages for regulatory, security, or accreditation purposes. This type of testing examines raw ingredients, consumable products, and packaging found not only in a production facility but also in locations such as shipping docks, farms, grocery stores, and more. Labs are often third parties accrediting a producer to a set of standards, ensuring regulatory compliance, conducting authenticity and adulteration testing, conducting security checks at borders, and applying contamination testing as part of an overall effort to track down the source of a foodborne illness. In the last case, the lab may not even be a traditional "food and beverage" lab but rather a [[public health laboratory]], highlighting in full the human safety elements associated with our food and water supplies. The human safety element is also seen in government labs such as the U.S. Department of Agriculture (USDA) Food Safety and Inspection Service's (FSIS) Field Service Laboratories, which "coordinate and conduct laboratory analytical services in support of the Agency's farm-to-table strategies in the disciplines of chemistry, microbiology, and pathology for food safety in meat, poultry, and egg products."<ref name="FSISLabs">{{cite web |url=https://www.fsis.usda.gov/science-data/laboratories-procedures/fsis-laboratories |title=FSIS Laboratories |publisher=Food Safety and Inspection Service, U.S. Department of Agriculture |date=26 April 2019 |accessdate=13 August 2022}}</ref> In addition to ensuring a safer food supply, society also benefits from these and similar labs by better holding producers accountable for their production methods and obligations.
| |
| | |
| ==Conclusion==
| |
| This brief topical article sought to answer "what is the importance of a food and beverage testing laboratory to society?" It notes that in particular,
| |
| | |
| ==References==
| |
| {{Reflist|colwidth=30em}}
| |
| | |
| <!---Place all category tags here-->
| |
| [[Category:LIMS FAQ articles (added in 2022)]]
| |
| [[Category:LIMS FAQ articles (all)]]
| |
| [[Category:LIMS FAQ articles on food and beverage]]
| |
 |
This is sublevel5 of my sandbox, where I play with features and test MediaWiki code. If you wish to leave a comment for me, please see my discussion page instead. |
Sandbox begins below
Template:Short description
"LOQ" redirects here. For the company listed as LOQ on the London Stock Exchange, see
Lo-Q. For the airport in Botswana with
IATA code LOQ, see
Lobatse Airport.
The limit of detection (LOD or LoD) is the lowest signal, or the lowest corresponding quantity to be determined (or extracted) from the signal, that can be observed with a sufficient degree of confidence or statistical significance. However, the exact threshold (level of decision) used to decide when a signal significantly emerges above the continuously fluctuating background noise remains arbitrary and is a matter of policy and often of debate among scientists, statisticians and regulators depending on the stakes in different fields.
Significance in analytical chemistry
In analytical chemistry, the detection limit, lower limit of detection, also termed LOD for limit of detection or analytical sensitivity (not to be confused with statistical sensitivity), is the lowest quantity of a substance that can be distinguished from the absence of that substance (a blank value) with a stated confidence level (generally 99%).[1][2][3] The detection limit is estimated from the mean of the blank, the standard deviation of the blank, the slope (analytical sensitivity) of the calibration plot and a defined confidence factor (e.g. 3.2 being the most accepted value for this arbitrary value).[4] Another consideration that affects the detection limit is the adequacy and the accuracy of the model used to predict concentration from the raw analytical signal.[5]
As a typical example, from a calibration plot following a linear equation taken here as the simplest possible model:
where, 
corresponds to the signal measured (e.g. voltage, luminescence, energy, etc.), "Template:Mvar" the value in which the straight line cuts the ordinates axis, "Template:Mvar" the sensitivity of the system (i.e., the slope of the line, or the function relating the measured signal to the quantity to be determined) and "Template:Mvar" the value of the quantity (e.g. temperature, concentration, pH, etc.) to be determined from the signal ,[6] the LOD for "Template:Mvar" is calculated as the "Template:Mvar" value in which equals to the average value of blanks "Template:Mvar" plus "Template:Mvar" times its standard deviation "Template:Mvar" (or, if zero, the standard deviation corresponding to the lowest value measured) where "Template:Mvar" is the chosen confidence value (e.g. for a confidence of 95% it can be considered Template:Mvar = 3.2, determined from the limit of blank).[4]
Thus, in this didactic example:
There are a number of concepts derived from the detection limit that are commonly used. These include the instrument detection limit (IDL), the method detection limit (MDL), the practical quantitation limit (PQL), and the limit of quantitation (LOQ). Even when the same terminology is used, there can be differences in the LOD according to nuances of what definition is used and what type of noise contributes to the measurement and calibration.[7]
The figure below illustrates the relationship between the blank, the limit of detection (LOD), and the limit of quantitation (LOQ) by showing the probability density function for normally distributed measurements at the blank, at the LOD defined as 3 × standard deviation of the blank, and at the LOQ defined as 10 × standard deviation of the blank. (The identical spread along Abscissa of these two functions is problematic.) For a signal at the LOD, the alpha error (probability of false positive) is small (1%). However, the beta error (probability of a false negative) is 50% for a sample that has a concentration at the LOD (red line). This means a sample could contain an impurity at the LOD, but there is a 50% chance that a measurement would give a result less than the LOD. At the LOQ (blue line), there is minimal chance of a false negative.
Template:Wide image
Instrument detection limit
Most analytical instruments produce a signal even when a blank (matrix without analyte) is analyzed. This signal is referred to as the noise level. The instrument detection limit (IDL) is the analyte concentration that is required to produce a signal greater than three times the standard deviation of the noise level. This may be practically measured by analyzing 8 or more standards at the estimated IDL then calculating the standard deviation from the measured concentrations of those standards.
The detection limit (according to IUPAC) is the smallest concentration, or the smallest absolute amount, of analyte that has a signal statistically significantly larger than the signal arising from the repeated measurements of a reagent blank.
Mathematically, the analyte's signal at the detection limit (
) is given by:
where, 
is the mean value of the signal for a reagent blank measured multiple times, and 
is the known standard deviation for the reagent blank's signal.
Other approaches for defining the detection limit have also been developed. In atomic absorption spectrometry usually the detection limit is determined for a certain element by analyzing a diluted solution of this element and recording the corresponding absorbance at a given wavelength. The measurement is repeated 10 times. The 3σ of the recorded absorbance signal can be considered as the detection limit for the specific element under the experimental conditions: selected wavelength, type of flame or graphite oven, chemical matrix, presence of interfering substances, instrument... .
Method detection limit
Often there is more to the analytical method than just performing a reaction or submitting the analyte to direct analysis. Many analytical methods developed in the laboratory, especially these involving the use of a delicate scientific instrument, require a sample preparation, or a pretreatment of the samples prior to being analysed. For example, it might be necessary to heat a sample that is to be analyzed for a particular metal with the addition of acid first (digestion process). The sample may also be diluted or concentrated prior to analysis by means of a given instrument. Additional steps in an analysis method add additional opportunities for errors. Since detection limits are defined in terms of errors, this will naturally increase the measured detection limit. This "global" detection limit (including all the steps of the analysis method) is called the method detection limit (MDL). The practical way for determining the MDL is to analyze seven samples of concentration near the expected limit of detection. The standard deviation is then determined. The one-sided Student's t-distribution is determined and multiplied versus the determined standard deviation. For seven samples (with six degrees of freedom) the t value for a 99% confidence level is 3.14. Rather than performing the complete analysis of seven identical samples, if the Instrument Detection Limit is known, the MDL may be estimated by multiplying the Instrument Detection Limit, or Lower Level of Detection, by the dilution prior to analyzing the sample solution with the instrument. This estimation, however, ignores any uncertainty that arises from performing the sample preparation and will therefore probably underestimate the true MDL.
Limit of each model
The issue of limit of detection, or limit of quantification, is encountered in all scientific disciplines. This explains the variety of definitions and the diversity of juridiction specific solutions developed to address preferences. In the simplest cases as in nuclear and chemical measurements, definitions and approaches have probably received the clearer and the simplest solutions. In biochemical tests and in biological experiments depending on many more intricate factors, the situation involving false positive and false negative responses is more delicate to handle. In many other disciplines such as geochemistry, seismology, astronomy, dendrochronology, climatology, life sciences in general, and in many other fields impossible to enumerate extensively, the problem is wider and deals with signal extraction out of a background of noise. It involves complex statistical analysis procedures and therefore it also depends on the models used,[5] the hypotheses and the simplifications or approximations to be made to handle and manage uncertainties. When the data resolution is poor and different signals overlap, different deconvolution procedures are applied to extract parameters. The use of different phenomenological, mathematical and statistical models may also complicate the exact mathematical definition of limit of detection and how it is calculated. This explains why it is not easy to come to a general consensus, if any, about the precise mathematical definition of the expression of limit of detection. However, one thing is clear: it always requires a sufficient number of data (or accumulated data) and a rigorous statistical analysis to render better signification statistically.
Limit of quantification
The limit of quantification (LoQ, or LOQ) is the lowest value of a signal (or concentration, activity, response...) that can be quantified with acceptable precision and accuracy.
The LoQ is the limit at which the difference between two distinct signals / values can be discerned with a reasonable certainty, i.e., when the signal is statistically different from the background. The LoQ may be drastically different between laboratories, so another detection limit is commonly used that is referred to as the Practical Quantification Limit (PQL).
See also
References
Further reading
- "Limits for qualitative detection and quantitative determination. Application to radiochemistry". Analytical Chemistry 40 (3): 586–593. 1968. doi:10.1021/ac60259a007. ISSN 0003-2700.
External links
Template:BranchesofChemistry
Template:Authority control
