Stephan G Walch

Stephan G Walch
Chemisches und Veterinäruntersuchungsamt Karlsruhe | CVUA

Doctor of Public Health

About

77
Publications
46,161
Reads
How we measure 'reads'
A 'read' is counted each time someone views a publication summary (such as the title, abstract, and list of authors), clicks on a figure, or views or downloads the full-text. Learn more
917
Citations
Introduction
Stephan Walch is the CEO of the Chemisches und Veterinäruntersuchungsamt Karlsruhe. Stephan is committed to research in Public Health, Life Science and Food Science. His interest lies in food safety, food fraud and authenticity, residues, and contaminants, but also in hygiene and AMR. He is member of different national and international committees (such as Ph.Eur., USP, WHO/FAO JECFA, ISO). Expertise in a wide array of analytical methods is also one of his traits.
Additional affiliations
December 2016 - present
October 2014 - present
Technische Universität Kaiserslautern
Position
  • External Lecturer
Description
  • drinking water, mineral water, water: chemistry, microbiology, analysis and quality assurance
April 2013 - November 2016
Institute for Food Chemistry Speyer
Position
  • Managing Director
Education
March 2011 - September 2019
September 2001 - March 2004
Karlsruhe Institute of Technology
Field of study
  • toxicology and food chemistry
September 1997 - November 2000
Universität Heidelberg
Field of study
  • Pharmaceutical Sciences

Publications

Publications (77)
Article
Full-text available
The use of the flowers (blossoms) of the coffee plant (genus Coffea) has been neglected over the years, as the focus was primarily on cost-efficient production of coffee beans. Because of societal changes and economic pressures, there is an increasing demand for sustainability, so that the focus widened also toward the various by-products of the co...
Article
Full-text available
Introduction: Recent research claimed that CBD in commercial electronic cigarette (e-cigarette) liquids can be converted into psychotropic amounts of Δ9-THC. This study aims to validate this claim using a realistic e-cigarette setup. In addition, this study also investigates if such a conversion may occur during smoking of CBD-rich cannabis joints....
Preprint
Full-text available
At present, foods containing cannabidiol (CBD) and other cannabinoids are internationally being widely advertised and sold in increasing quantities. In the European Union (EU), these products require pre-marketing authorisation under the novel food regulation, so that all available CBD oils and CBD-containing food supplements in the EU are currentl...
Article
Das Interesse von Verbrauchern an hanfhaltigen Lebensmitteln, insbesondere solchen mit hohen Gehalten an Cannabidiol (CBD), wächst kontinuierlich. Besonders beliebt sind CBD-Nahrungsergänzungsmittel, die aufgrund ihrer vermeintlich positiven Wirkung auf die Gesundheit stark beworben und verkauft werden [1]. Nachdem im November 2020 durch den EuGH e...
Article
The conversion of cannabidiol (CBD) to the psychoactive ∆9-tetrahydrocannabinol (THC) in electronic cigarettes is a repeatedly discussed topic, regarding the consumer safety of CBD liquids. Previous publications on this topic have reported contradictory results [1,2], raising the need for further research. This study investigated, whether THC can b...
Preprint
Full-text available
At present, foods containing cannabidiol (CBD) and other cannabinoids are internationally being widely advertised and sold in increasing quantities. In the European Union (EU), these products require pre-marketing authorisation under the novel food regulation, so that all available CBD oils and CBD-containing food supplements in the EU are currentl...
Preprint
Full-text available
Introduction: Recent research claimed that cannabidiol (CBD) in commercial electronic cigarette (e-cigarette) liquids can be converted into psychotropic amounts of ∆9-tetrahydrocannabinol (THC). This study aims to validate this claim using a realistic e-cigarette setup. Additionally, this study also investigates if such a conversion may occur durin...
Article
Full-text available
Background: In the past 60 years, Cannabis sativa L. has been an object of increasing interest because of the psychotropic effects of some of its constituents. These effects mainly arise from the cannabinoid Δ9-tetrahydrocannabinol (Δ9-THC). C. sativa species also synthesize and accumulate the non-psychotropic compound cannabidiol (CBD). Due to th...
Article
Full-text available
Information about unsafe foods or feeds must be exchanged between European Union (EU) member states as quickly as possible. This is why the EU’s Rapid Alert System for Food and Feed (RASFF) exists. It helps to ensure that products that may be harmful to health do not enter the market or can be specifically withdrawn from the market. Different notif...
Preprint
Introduction: Recent research claimed that cannabidiol (CBD) in commercial electronic cigarette (e-cigarette) liquids can be converted into psychotropic amounts of ∆9-tetrahydrocannabinol (THC). This study aims to validate this claim by a realistic e-cigarette setup. Additionally, this study also investigates if such a conversion may occur during s...
Preprint
Full-text available
Introduction: Recent research claimed that cannabidiol (CBD) in commercial electronic cigarette (e-cigarette) liquids can be converted into psychotropic amounts of ∆9-tetrahydrocannabinol (THC). This study aims to validate this claim by a realistic e-cigarette setup. Additionally, this study also investigates if such a conversion may occur during s...
Preprint
Full-text available
Introduction: Recent research claimed that cannabidiol (CBD) in commercial electronic cigarette (e-cigarette) liquids can be converted into psychotropic amounts of ∆9-tetrahydrocannabinol (THC). This study aims to validate this claim by a realistic e-cigarette setup. Additionally, this study also investigates if such a conversion may occur during s...
Article
Full-text available
9-Tetrahydrocannabinol (THC) is known as the main psychotropic compound present in the hemp plant. It also occurs in commercially available hemp food products and may have adverse effects on consumers. This article provides an overview of the current situation of the THC content in hemp food products in Germany in recent years. The content of THC w...
Preprint
Through its suggestive name, non-targeted methods (NTMs) do not aim at a predefined "needle in the haystack". Instead, they exploit all the constituents of the haystack. This new form of analytical methods is increasingly finding applications in food and feed testing. However, the concepts, terms, and considerations related to this burgeoning field...
Preprint
Through its suggestive name, non-targeted methods (NTMs) do not aim at a predefined "needle in the haystack". Instead, they exploit all the constituents of the haystack. This new form of analytical methods is increasingly finding applications in food and feed testing. However, the concepts, terms, and considerations related to this burgeoning field...
Article
Full-text available
Produkte mit Hanfextrakt sind als neuartige Lebensmittel ohne Zulassung weiter nicht verkehrsfähig. Der Europäische Gerichtshof schließt aber die Einstufung von Cannabidiol als Betäubungsmittel aus. Für Hanfblätter und -blüten muss laut BGH ein Missbrauch zu Rauschzwecken ausgeschlossen werden, jedoch ist dann gegebenenfalls eine Abgabe auch an End...
Article
Full-text available
An interesting and valuable discussion has arisen from our recent article (Lachenmeier et al., 2020) and we are pleased to have the opportunity to expand on the various points we made. Equally important, we wish to correct several important misunderstandings that were made by Kruse and Beitzke (2020) on behalf of the European Industrial Hemp Associ...
Article
Full-text available
Cannabidiol (CBD)-containing products are widely marketed as over the counter products, mostly as food supplements. Adverse effects reported in anecdotal consumer reports or during clinical studies were first assumed to be due to hydrolytic conversion of CBD to psychotropic Δ ⁹ -tetrahydrocannabinol (Δ ⁹ -THC) in the stomach after oral consumption....
Article
Full-text available
Acrylamide is probably carcinogenic to humans (International Agency for Research on Cancer, group 2A) with major occurrence in heated, mainly carbohydrate-rich foods. For roasted coffee, a European Union benchmark level of 400 µg/kg acrylamide is of importance. Regularly, the acrylamide contents are controlled using liquid chromatography combined w...
Preprint
Full-text available
Acrylamide is probably carcinogenic to humans (International Agency for Research on Cancer, group 2A) with major occurrence in heated, mainly carbohydrate-rich foods. For roasted coffee, a European Union benchmark level of 400 µg/kg acrylamide is of importance. Regularly, the acrylamide contents are controlled using liquid chromatography combined w...
Article
Full-text available
The food additive sorbic acid is considered as an effective preservative for certain cereal products, and propionic acid is commonly added in bakery wares, e.g., bread and fine bakery wares. The aim of this study was to develop and validate a new nuclear magnetic resonance spectroscopy (1H NMR) method for the routine screening and quantification of...
Preprint
Full-text available
The food additive sorbic acid is considered as an effective preservative for certain cereal products, and propionic acid is commonly added in bakery wares, e.g. bread and fine bakery wares. The aim of this study is to develop and validate a new nuclear magnetic resonance spectroscopy (¹H NMR) method for routine screening and quantification of...
Article
Hanfprodukte und insbesondere solche mit Cannabidiol sind derzeit in aller Munde und beschäftigen alle Bereiche der Lebensmittelüberwachung mit Fragen der Untersuchung, Verkehrsfähigkeitsbeurteilung im Abgrenzungsbereich zum Betäubungsmittelgesetz, sowie den sich daraus ergebenden teilweise nichttrivialen Problemen für Lebensmittelkontrolle und -vo...
Article
Die zentrale Frage zur Verkehrsfähigkeit von Cannabidiol (CBD), sowie Produkten mit Hanfblüten und Hanfextrakt ist neben der notwendigen Novel Food-Zulassung die Prüfung der Einstufung als Betäubungsmittel, die nach Art. 2 Buchst. g der Verordnung (EG) Nr. 178/2002 einen sofortigen Ausschluss aus dem Lebensmittelbereich bedingen würde und die Produ...
Article
Full-text available
Due to legal regulations, the rise of globalised (online) commerce and the need for public health protection, the analysis of spirit drinks (alcoholic beverages >15% vol) is a task with growing importance for governmental and commercial laboratories. In this article a newly developed method using nuclear magnetic resonance (NMR) spectroscopy for th...
Preprint
Full-text available
Due to legal regulations, the rise of globalised (online) commerce and the need for public health protection, the analysis of spirits (alcoholic beverages > 15 % vol) is a task with growing importance for governmental and commercial laboratories. In this article a newly developed method using nuclear magnetic resonance (NMR) spectroscopy for the si...
Article
Full-text available
An interesting and valuable discussion has arisen from our recent article (Lachenmeier et al., 2020) and we are pleased to have the opportunity to expand on the various points we made. Equally important, we wish to correct several important misunderstandings that were made by Kruse and Beitzke (2020) on behalf of the European Industrial Hemp Associ...
Article
Full-text available
Cannabidiol (CBD)-containing products are widely marketed as over the counter products, mostly as food supplements, to avoid the strict rules of medicinal products. Side-effects reported in anecdotal consumer reports or during clinical studies were first assumed to be due to hydrolytic conversion of CBD to psychotropic Δ9-tetrahydrocannabinol (Δ9-T...
Article
Full-text available
The case of cannabidiol (CBD) makes the deficits in the current regulatory approach for food supplements clearly evident. Therefore, we strongly urge for a paradigm shift towards pre-marketing approval.
Article
Background Coffee is a popular beverage with two species, Coffea canephora and C. arabica, being commercially exploited. The quality and commercial value of coffee is dependent on species and processing. C. arabica typically obtains a higher price on the market compared to C. canephora. Coffee beans undergo roasting during processing, resulting in...
Article
Full-text available
Zusammenfassung Im Novel-Food-Katalog der Europäischen Kommission sind Cannabidiol (CBD) und Hanfextraktprodukte als neuartig eingestuft und benötigen somit vor dem ersten Inverkehrbringen eine Zulassung. Vonseiten der Lebensmittelunternehmen wird aber eine Vielzahl derartiger Produkte ohne Zulassung in den Verkehr gebracht und von der amtlichen Ü...
Article
Full-text available
Cannabidiol (CBD)-containing products are widely marketed as over the counter products, mostly as food supplements, to avoid the strict rules of medicinal products. Side-effects reported in anecdotal consumer reports or during clinical studies were first assumed to be due to hydrolytic conversion of CBD to psychotropic Δ ⁹ -tetrahydrocannabinol (TH...
Article
Full-text available
Monitoring coffee quality as a means of detecting and preventing economically motivated fraud is an important aspect of international commerce today. Therefore, there is a compelling need for rapid high throughput validated analytical techniques such as quantitative proton nuclear magnetic resonance (NMR) spectroscopy for screening and authenticity...
Article
Full-text available
Kurzfassung: Hanfhaltige Lebensmittel liegen voll im Trend. Großer Popularität erfreuen sich derzeit neuartige Nahrungsergänzungsmittel mit Cannabisextrakt, für die vor allem mit dem nicht-psychotropen Cannabinoid Cannabidiol (CBD) und dessen vermeintlich positiven Wir-kungen auf die Gesundheit geworben wird. Seit dem Aufkommen dieser CBD-Produkte...
Preprint
Full-text available
Monitoring coffee quality as a means of detecting and preventing economically motivated fraud is an important aspect of international commerce today. Therefore, there is a compelling need for rapid high throughput validated analytical techniques such as quantitative proton NMR spectroscopy for screening and authenticity testing. For this reason, we...
Article
Seit dem Vergiftungsfall eines Säuglings im Jahre 2005 durch Milch, in der Mohnsaat ausgekocht wurde, stehen die Untersuchungen auf pharmakologisch wirksame OpiatAlkaloide im Fokus der Lebensmittelüberwachung in Karlsruhe [1]. Mohnsaaten können gewinnungsbedingt unerwünscht hohe Gehalte arzneilich hochpotenter Mohnalkaloide enthalten. Hierzu zählen...
Article
Cannabidiol (CBD) ist, im Gegensatz zu Δ9-Tetrahydrocannabinol (THC), ein nicht psychoaktives Cannabinoid. Es wird derzeit aufgrund seiner möglichen entkrampfenden, entzündungshemmenden, angstlösenden sowie antiemetischen Wirkungen als Arzneimittel, z.B. zur Behandlung von Epilepsie, getestet. CBD-Produkte aller Art können aber inzwischen meist unt...
Article
Full-text available
Zusammenfassung Seit dem 1996 aufgehobenen Anbauverbot für Pflanzen der Spezies Cannabis sativa L. (sog. Faserhanf) mit geringem Gehalt des psychoaktiven Inhaltsstoffs Δ9-Tetrahydrocannabinol (THC) wird eine Vielzahl daraus hergestellter Lebensmittel angeboten. Als Beurteilungshilfe für die amtliche Lebensmittelüberwachung werden in dieser Übersic...
Preprint
Full-text available
Cannabidiol (CBD)-containing products are widely marketed as over the counter products, mostly as food supplements, to avoid the strict rules of medicinal products. Side-effects reported in anecdotal consumer reports or during clinical studies were first assumed to be due to hydrolytic conversion of CBD to psychoactive Δ ⁹ -tetrahydrocannainol (THC...
Article
The recent article of Bujdosó et al. [1] compares analytical data of a collective of recorded spirits (n=119) with unrecorded spirits (n=87) regarding the contents of ethanol, methanol and selected higher alcohol such as 1-propanol (termed other aliphatic alcohols, OAA). The results were used to obtain a quantitative risk assessment using the margi...
Chapter
The World Health Organization estimates that globally out of the 6.2 L of pure alcohol consumed per person (15 + years), 25% is unrecorded alcohol. Unrecorded alcohol is defined as alcohol not registered in the legislation where it is consumed and includes homemade, surrogate, and counterfeit alcohols. Since the production, distribution, and consum...
Article
This article points out some important requirements for accurate analysis of MOSH (mineral oil saturated hydrocarbons) and MOAH (mineral oil aromatic hydrocarbons) using NMR spectroscopy. These include the selection of integration windows of MOSH not above delta 3.0 ppm as this might lead to inclusion of non-aliphatic compounds, but also the exclus...
Article
Full-text available
In cosmetic products, hydrocarbons from mineral oil origin are used as ingredients in a wide variety of consistency, from liquid oil to solid wax. Refined mineral oil hydrocarbons consist of MOSH (mineral oil saturated hydrocarbons) and a low proportion of MOAH (mineral oil aromatic hydrocarbons). MOSH and MOAH comprise a variety of chemically simi...
Article
Full-text available
The four heat-induced coffee contaminants—acrylamide, furfuryl alcohol (FA), furan and 5-hydroxymethylfurfural (HMF)—were analyzed in a collective of commercial samples as well as in Coffea arabica seeds roasted under controlled conditions from very light Scandinavian style to very dark Neapolitan style profiles. Regarding acrylamide, average conte...
Chapter
Der Onlinehandel mit Erzeugnissen nach dem Lebensmittel – und Futtermittelgesetzbuch (LFGB) und auch mit Erzeugnissen aus den Rand- und Graubereichen wie Tabakerzeugnissen oder (oft illegalen) Arzneimitteln wächst stetig und stellt die amtliche Kontrolle vor neue Herausforderungen. Aber selbst konventionelle Lebensmittel werden mehr denn je in klas...
Preprint
Full-text available
The three heat-induced coffee contaminants acrylamide, furfuryl alcohol (FA) and 5-hydroxymethylfurfural (HMF) were analyzed in a collective of commercial samples as well as in Coffea arabica seeds roasted under controlled conditions from very light Scandinavian style to very dark Neapolitan style profiles. Regarding acrylamide, average contents in...
Article
Beverage fraud involving counterfeiting of brand spirits is an increasing problem not only due to deception of the consumer but also because it poses health risks e.g. from possible methanol admixture. Suspicious spirit samples from Russia and Kenya were analysed using 1H nuclear magnetic resonance (NMR) spectroscopy in comparison to authentic prod...
Article
Unrecorded alcohol consumption may be assessed by combining data from expert assessments and nationally representative surveys. While such a multivariate approach improves previous knowledge, underestimates may relate to the weak data available in some countries, exclusion of most vulnerable populations in surveys and potential unawareness of consu...
Article
Full-text available
Mineral oils (such as paraffinum liquidum or white oil), which consist of mineral oil saturated hydrocarbons (MOSH) and mineral oil aromatic hydrocarbons (MOAH), are widely applied in various consumer products such as medicines and cosmetics. Contamination of food with mineral oil may occur by migration of mineral oil containing products from packa...
Article
Nuclear magnetic resonance (NMR) spectroscopy has achieved increased application in the field of food authenticity control. Its instrumental variability is very low so that it is possible to compile large databases of authentic spectra. Adulterations in food fraud cases can be detected and quantification of compounds for regulatory limits control c...
Article
Full-text available
A simple, rapid, and selective quantitative nuclear magnetic resonance spectroscopic method was evaluated for the determination of the content of fluorinated pharmaceuticals. 19F NMR spectra were either obtained in dimethylsulfoxide-d 6 or aqueous buffer, using trifluoroacetic acid as internal standard. Quantification of 13 fluorine-containing phar...
Article
Full-text available
Die Bezeichnung Schwarzwaldforelle ist seit dem 25.11.1997 in das Verzeichnis der geographisch geschützten Angaben (g. g. A.) der EU aufgenommen und darf seither nur noch nach den in den entsprechenden EU-Verordnungen (z. Z. VO (EU) 1151/2012) niedergelegten Regeln erzeugt und in Verkehr gebracht werden. Wenn die Bezeichnung "Schwarzwaldforelle" ve...
Article
Full-text available
Mineral hydrocarbons consist of two fractions, mineral oil saturated hydrocarbons (MOSH) and mineral oil aromatic hydrocarbons (MOAH). MOAH is a potential public health hazard because it may include carcinogenic polycyclic compounds. In the present study, 400 MHz nuclear magnetic resonance (NMR) spectroscopy was introduced, in the context of offici...
Article
Full-text available
Counterfeit alcohol belongs to the category of unrecorded alcohol not reflected in official statistics. The internet trade of alcoholic beverages has been prohibited by the Russian Federation since 2007, but various sellers still offer counterfeit spirits (i.e., forged brand spirits) over the internet to Russian consumers, mostly in a non-deceptive...
Article
As a dimension of exposure, alcohol quality (better termed ‘alcohol composition') is currently considered only for liver cirrhosis. However, in relation to methanol admixture, it may be an important factor in causing mortality and morbidity, especially in unrecorded surrogate alcohols.
Preprint
Full-text available
Mineral hydrocarbons consist of two fractions, mineral oil saturated hydrocarbons (MOSH) and mineral oil aromatic hydrocarbons (MOAH). MOAH is a potential public health hazard because it may include carcinogenic polycyclic compounds. In the present study, 400 MHz nuclear magnetic resonance (NMR) spectroscopy was introduced, in the context of offici...
Preprint
Full-text available
Counterfeit alcohol belongs to the category of unrecorded alcohol not reflected in official statistics. The internet trade of alcoholic beverages has been prohibited by the Russian Federation since 2007, but various sellers still offer counterfeit spirits (i.e., forged brand spirits) over the internet to Russian consumers, mostly in a non-deceptive...
Article
Nach der Lebensmittelinformationsverordnung sind bestimmte Pflichtangaben auf Lebensmittelverpackungen in einer Mindestschriftgröße mit einer x-Höhe von 1,2 mm anzugeben. Zur Messung ist nach QS-Vorgaben eine Rückführung notwendig. Am CVUA Karlsruhe hat sich dafür ein System aus Präzisionsmessskala mit digitalem Mikroskop bewährt.
Data
Supplementary Figures S1-S13 (19F NMR spectra of all investigated compounds).
Technical Report
Full-text available
In the first part of the NMR technical report (see Guide to NMR Method Development and Validation – Part I: Identification and Quantification), the special criteria to facilitate development of NMR-based applications is described. These guidelines (Part I) mostly deal with general requirements, such as NMR spectra acquisition, identification, devel...
Article
Full-text available
A methodology that utilizes (1)H-NMR spectroscopy has been developed to simultaneously analyze toxic terpenes (thujone and camphor), major polyphenolic compounds, the total antioxidant capacity (ORAC) and the Folin-Ciocalteu (FC) index in foods and medicines containing sage. The quantitative determination of rosmarinic acid (limit of detection (LOD...
Article
Halicioglu et al. reported on two children who manifestedgeneralized tonic-clonic seizures after accidental exposure to sage(Salvia officinalis L.) oil [1]. Their report is important not onlyfrom a clinical standpoint, but because it provides insights intothe toxicology of essential oils in humans, which is currently basedpredominantly on knowledge...
Article
Full-text available
Sage (Salvia officinalis L.) is used as an herbal medicinal product, with the most typical form of application as infusion with boiling water (sage tea). The well-established traditional uses include symptomatic treatment of mild dyspeptic complaints, the treatment of inflammations in the mouth and the throat, and relief of excessive sweating and r...
Article
Sage tea, the aqueous infusion of dried sage leaves (Salvia officinalis L.), is used as a form of food as well as a form of traditional herbal medicine. Several in vivo and in vitro studies point to sage polyphenols as active principles that may inhibit lipid peroxidation and improve antioxidant defences. This study describes an UHPLC methodology w...
Article
The use of thujone, a monoterpene ketone often present in sage (Salvia officinalis L.) or wormwood (Artemisia absinthium L.), for the treatment of diabetes mellitus was recently suggested in a study published in this journal. Evidence was based on the findings obtained in a diabetic rat model. After oral treatment with thujone (5 mg/kg bodyweight (...