Deliberate Adulteration Research Articles

Screening the quality of legal and illegal dietary supplements by LC-MS/MS

ABSTRACT Dietary supplements are widely consumed. However, the lack of mandatory testing results in limited data on their quality, particularly in Eastern Europe. In this study, 21 legally registered and 9 illegal supplements, seized from an underground facility by the Polish Police, were examined. Contaminants were screened by utilising high-performance liquid chromatography coupled with untargeted mass spectrometry. The analysis identified 32 contaminants in the 30 dietary supplements examined. Untargeted analysis revealed a concerning issue: the intentional adulteration of both legal and illegal supplements with pharmacologically active substances that are prohibited in this category of products. This study indicated that many dietary supplements are of low quality due to deliberate adulteration or inadequate manufacturing conditions. The presence of unregistered or unapproved substances in these supplements poses serious health risks. Strong legal regulations are essential to address this issue effectively.

A robust set of qPCR methods to evaluate adulteration in major spices and herbs

Consumers and companies associated with food or pharmaceuticals rely on spices and herbs in various forms. Their intricate supply chains, elevated prices, and low-volume production render them vulnerable to fraudulent practices. However, comprehensive methodologies to detect adulterants remain scarce, impeding national control laboratories from enforcing European and national legislation. In this study, we present quantitative real-time PCR (qPCR) methods designed to identify the top five adulterants of each of six commonly consumed spices and herbs: paprika/chili, turmeric, saffron, cumin, oregano and black pepper. The specificity of each method was confirmed by qPCR analysis of a large collection of relevant plant species. Each authentic sample was combined with its respective top five adulterants as identified in the European Union-wide coordinated control plan on herbs and spices in 2021 or in the existing literature. These binary mixtures were used to evaluate the method's performance with respect to sensitivity, linearity and trueness at four levels of adulterants concentration. Detection was also investigated in multi-adulterated samples. These SYBR™ Green-based qPCR methods enable the specific detection of adulterants, and their sensitivity allows for the distinction between inadvertent contamination and deliberate adulteration. Altogether, these methods contribute to safeguard the authenticity of these high-value commodities.

Phthalates: The Main Issue in Quality Control in the Beverage Industry

Phthalate esters (PAEs) are a group of chemicals used to improve the flexibility and durability of plastics. The chemical properties and the resistance to high temperatures promote their degradation and release into the environment. Food and beverages can be contaminated by PAEs through the migration from packaging material because they are not covalently bound to plastic and also via different kinds of environmental sources or during processing. For instance, alcoholic drinks in plastic containers are a particular risk, since the ethanol contained provides a good solubility for PAEs. According to its role as an endocrine disruptor compound and its adverse effects on the liver, kidney, and reproductive and respiratory systems, the International Agency on Research Cancer (IARC) classified di-(2-ethylhexyl) phthalate (DEHP) as a possible human carcinogen. For this reason, to control human exposure to PAEs, many countries prohibited their use in food as non-food substances. For example, in Europe, the Commission Regulation (EU) 2018/2005 restricts the use of DEHP, dibutyl phthalate (DBP), benzyl butyl phthalate (BBP), and diisobutyl phthalate (DiBP) to a concentration equal to or below 0.1 by weight in plasticizers in articles used by consumers or in indoor areas. There are reports from the US Food and Drug Administration (FDA) that some beverages (and food as well), particularly fruit juices, contain high levels of phthalates. In some cases, the deliberate adulteration of soft drinks with phthalate esters has been reported. This paper would like to show the difficulties of performing PAE analysis in beverage matrices, in particular alcoholic beverages, as well as the main solutions provided for quality control in the industrial branches.

Adulteration detection of Gastrodia elata Blume and its commercial products using chloroplast DNA marker-based species-specific PCR assays

Gastrodia elata Blume has been recognized as a precious herbal medicine for thousands years due to its abundant bioactive ingredients and health-promoting features. The inadvertent or intentional adulteration of G. elata poses a severe crisis for consumers and significantly disrupts the market order. Therefore, accurate discrimination of G. elata from its adulterants is crucial to ensure its therapeutic effects and protect consumers’ interests. In this study, two species-specific PCR assays for molecular discrimination of G. elata from its five adulterants were established by targeting the chloroplast rps12 and clpP regions, respectively. Both of the assays can reliably identify as little as 0.1 % of deliberate adulteration with a detection threshold of only 0.01 ng of template DNA, and the assays are effective in detecting adulteration within G. elata as well as its commercial extracts. The present study provide a highly sensitive and reliable method for ascertaining the authenticity of G. elata and its commercial products, and the methodology can be employed in the authenticity and adulteration detection of other herbal products.

Exploring Deep Learning to Predict Coconut Milk Adulteration Using FT-NIR and Micro-NIR Spectroscopy.

Accurately identifying adulterants in agriculture and food products is associated with preventing food safety and commercial fraud activities. However, a rapid, accurate, and robust prediction model for adulteration detection is hard to achieve in practice. Therefore, this study aimed to explore deep-learning algorithms as an approach to accurately identify the level of adulterated coconut milk using two types of NIR spectrophotometer, including benchtop FT-NIR and portable Micro-NIR. Coconut milk adulteration samples came from deliberate adulteration with corn flour and tapioca starch in the 1 to 50% range. A total of four types of deep-learning algorithm architecture that were self-modified to a one-dimensional framework were developed and tested to the NIR dataset, including simple CNN, S-AlexNET, ResNET, and GoogleNET. The results confirmed the feasibility of deep-learning algorithms for predicting the degree of coconut milk adulteration by corn flour and tapioca starch using NIR spectra with reliable performance (R2 of 0.886-0.999, RMSE of 0.370-6.108%, and Bias of -0.176-1.481). Furthermore, the ratio of percent deviation (RPD) of all algorithms with all types of NIR spectrophotometers indicates an excellent capability for quantitative predictions for any application (RPD > 8.1) except for case predicting tapioca starch, using FT-NIR by ResNET (RPD < 3.0). This study demonstrated the feasibility of using deep-learning algorithms and NIR spectral data as a rapid, accurate, robust, and non-destructive way to evaluate coconut milk adulterants. Last but not least, Micro-NIR is more promising than FT-NIR in predicting coconut milk adulteration from solid adulterants, and it is portable for in situ measurements in the future.

Successful campaign in Bangladesh eliminates deliberate adulteration of turmeric with PY-34

Successful campaign in Bangladesh eliminates deliberate adulteration of turmeric with PY-34

Validation of Two Real-Time PCR Approaches for the Relative Quantitation of Pork and Horse DNA in Food Samples

Two real-time PCR methods for the relative quantitation of DNA from meat species in food samples are described: these methods are applicable for horse in processed beef meat products, and pork in raw/processed beef meat products. Test samples were prepared using raw meat admixtures or processed horse/pork in beef food products made to an industry-standard recipe. The methods were subjected to single laboratory method validation, evaluating the performance characteristics of specificity, PCR efficiency and r-squared (r2), Limit of Detection (LOD), Limit of Quantitation (LOQ), and precision and trueness. A limited UK-based inter-laboratory trial of the two methods was completed involving four participating laboratories. Full statistical analysis of the data qualified the applicability of the methods for accurate and sensitive trace-level analysis. The methods were deemed fit for purpose for reproducibly distinguishing between adventitious contamination at 0.1% (w/w), the level for further enforcement action at 1% (w/w), and a level representative of deliberate economically motivated adulteration (10% (w/w)). The data provided evidence that the precision of the two methods was applicable for qualitative and quantitative detection at topically important levels of adulteration. This work has added significant value to the current state of the art in quantitative determination of topical meat species adulteration, allowing analysts to distinguish between adventitious contamination and deliberate adulteration. The resulting methods described in this paper can easily be deployed and used by analytical laboratories for controls and due-diligence testing based on standard laboratory equipment.

Application of direct injection-ion mobility spectrometry-mass spectrometry (DI-IMS-MS) for the analysis of phenolics in honeybush and rooibos tea samples

Consumer awareness of the health benefits of herbal teas such as rooibos and honeybush has led to an increase in production demand and to inevitable accidental or deliberate adulteration. In this study, direct injection-ion mobility spectrometry-mass spectrometry (DI-IMS-MS) is proposed as a rapid methodology for the differentiation of rooibos and honeybush blends (adulterations). Analytical data was obtained from 100 rooibos, 130 honeybush and 7 blend samples. Principal component analysis (PCA) showed differences between samples of rooibos and honeybush blends, and further showed the diagnostic value of marker compounds in distinguishing Cyclopia intermedia, C. genistoides and C. subternata, mainly used for honeybush production. Markers such as eriodictyol-C-hexose isomers, orientin, aspalathin, and vitexin were characteristic of blends containing more than 80 % rooibos plant material, and quinic acid, iriflophenone-3-C-glucoside-4-O-glucoside, C-glycosylxanthones isomers (mangiferin and isomangiferin), and eriodictyol were characteristic of blends containing more than 80 % C. intermedia plant material. Furthermore, the C-glycosylxanthones isomers (mangiferin and isomangiferin) were prominent in C. genistoides, quinic acid was prominent in C. subternata and piscidic acid was prominent in C. intermedia plant material. Phenolic compounds in the herbal teas were further characterised based on an array of complementary descriptors (e.g., retention time, arrival times, accurate mass information, tandem MS fragmentation data, and TWCCSN2) to strengthen compound identification.

Hygienic knowledge and practices of milk vending machine handlers in the informal settlements of Nairobi, Kenya

Background: Poor milk handling practices due to lack of knowledge or deliberate adulteration compromises the safety of milk and that of the consumer. With the increase of milk vending machines in informal settlements, the knowledge and practices of vendors concerning milk hygiene are critical in determining milk safety. The operation of milk vending machines is guided by strict regulations that aim at ensuring proper practices among milk handlers, but the level of implementation among milk vendors is questionable. This study sought to establish hygienic knowledge and handling practices of vendors operating milk vending machines in Nairobi’s informal settlements of Kibra and Dagoretti North. Methods: Using a cross-sectional study design, 37 milk vendors were interviewed at the study setting with the aid of questionnaires. Data was then recorded in datasheets and analyzed using frequencies, correlation, and t-test with the aid of Statistical Package for Social Sciences software. Results: The mean percentage score for knowledge and practices was 68.83% and 54.05%, respectively. The knowledge and practices of vendors significantly improved with the increase in their level of education (p=0.04 and p=0.02). There was a significantly positive correlation between knowledge and practices (r=0.626, p=0.000). Conclusions: There is a low level of hygienic knowledge and poor practices among vendors operating milk vending machines in the study area. The efforts by the regulator to ensure proper implementation of the regulations was also not sufficient. Training is required to improve the hygienic knowledge and practices of milk vending machine handlers in informal settlements. Frequent inspections should also be carried out in the informal settlements to ensure proper implementation of regulations on the operation of milk vending machines.

Authentication of berries and berry-based food products.

Berries represent one of the most important and high-valued group of modern-day health-beneficial "superfoods" whose dietary consumption has been recognized to be beneficial for human health for a long time. In addition to being delicious, berries are rich in nutrients, vitamins, and several bioactive compounds, including carotenoids, flavonoids, phenolic acids, and hydrolysable tannins. However, due to their high value, berries and berry-based products are often subject to fraudulent adulteration, commonly for economical gain, but also unintentionally due to misidentification of species. Deliberate adulteration often comprises the substitution of high-value berries with lower value counterparts and mislabeling of product contents. As adulteration is deceptive toward customers and presents a risk for public health, food authentication through different methods is applied as a countermeasure. Although many authentication methods have been developed in terms of fast, sensitive, reliable, and low-cost analysis and have been applied in the authentication of a myriad of food products and species, their application on berries and berry-based products is still limited. The present review provides an overview of the development and application of analytical chemistry methods, such as isotope ratio analysis, liquid and gas chromatography, spectroscopy, as well as DNA-based methods and electronic sensors, for the authentication of berries and berry-based food products. We provide an overview of the earlier use and recent advances of these methods, as well as discuss the advances and drawbacks related to their application.

Harnessing multiplex polymerase chain reaction assay for convenient and simultaneous differentiation of testudinis carapax et plastrum from trionycis carapax

Background: Testudinis Carapax et Plastrum (TCP, Guijia) and Trionycis Carapax (TC, Biejia), which made from the shell of Chinemys reevesii (CR) and Pelodiscus sinensis (PS), were two kinds of widely used animal-derived Traditional Chinese medicine (TCM). Some cheap substitutes such as the carapace and plastron of Trachemys scripta (TS), Mauremys sinensis (MS), or Apalone ferox (AF) shells obtained from restaurants are sometimes used, which expose the public health to a high risk and cause unfair competitions in the market. Objective: The objective of the study was to develop a multiplex polymerase chain reaction (PCR) approach to simultaneously differentiate five Chelonia species and identify adulteration of two natural products. Materials and Methods: Five novel species-specific primers were designed for CR, TS, MS, PS, and AF, followed by optimization of PCR conditions and validation for specificity and sensitivity. Then, a deliberate mixture was analyzed to verify the capability of adulteration detection. Finally, it was used to examine commercial products. Results: The developed method proved to be highly specific and detection limit was 1 ng for all the species tested. Particularly, it was still applicable and reliable when processed products or deliberate adulteration were examined. Two batches of commercial raw TCP products were identified to be counterfeited by TS using the newly proposed approach. Conclusion: The newly proposed multiplex PCR method showed sufficient merits to be readily employed as a regular means to authenticate edible and medicinal TCM products made of TCP and TC.

A review on molecular techniques employed for authentication of Indian medicinal plants

Traditional medical systems are advancing to the level of modern medicines in treatment and preventive aspects. The increased trade in medicinal plants provides income source for herbalists while substitution of rare ingredients with cheaper and more readily available species is misleading the end users. The prime cause of the problems associated with the standardization of medicinal plants is complex composition of herbal drugs used in the form of whole plants, plant parts or extracts. Deliberate adulteration of intended ingredients are posing difficulty in distinguishing the genuine resources. Authentication of medicinal plants by recent molecular techniques is inevitable for herbal drug industries, researchers and academia. Of late, herbal genomics, molecular studies of medicinal plants and powerful next generation sequencing techniques have been emerged to transform the current knowledge. A compilation of various molecular markers used, their efficiency in barcoding for the purpose of accurate authentication of herbal drugs has been attempted in this study. Data were collected from previous literature and online repositories like NCBI, Pubmed etc. There are various molecular techniques that can be exploited for authentication of medicinal plants such as Restriction Fragment Length Polymorphism (RFLP), Random Amplified Polymorphic DNA (RAPD), Amplified Fragment Length Polymorphism (AFLP), Sequence Characterized Amplified Region (SCAR), Selective Amplification of Microsatellite polymorphic loci (SAMPL), Simple Sequence Repeats (SSR), Inter Simple Sequence Repeat (ISSR), DNA barcoding, Next Generation Sequencing Techniques etc. Some of medicinal plants were reported having molecular data useful in plant identification. The genomic data of poly herbal formulations helps for scientific validation and universal recognition. Even though the challenges associated with reprehensibility, primer designing, amplification products of molecular markers and troubles related with DNA isolation and purification, become the major obstacle in front of researchers. It is high time to focus these novel strategies for proper identification to ensure the fidelity of traditional herbal products and there by promoting a step towards the global acceptance of our indigenous medicinal systems.

Chemical Barcoding: A Nuclear-Magnetic-Resonance-Based Approach To Ensure the Quality and Safety of Natural Ingredients.

One of the greatest challenges facing the functional food and natural health product (NHP) industries is sourcing high-quality, functional, natural ingredients for their finished products. Unfortunately, the lack of ingredient standards, modernized analytical methodologies, and industry oversight creates the potential for low quality and, in some cases, deliberate adulteration of ingredients. By exploring a diverse library of NHPs provided by the independent certification organization ISURA, we demonstrated that nuclear magnetic resonance (NMR) spectroscopy provides an innovative solution to authenticate botanicals and warrant the quality and safety of processed foods and manufactured functional ingredients. Two-dimensional NMR experiments were shown to be a robust and reproducible approach to capture the content of complex chemical mixtures, while a binary normalization step allows for emphasizing the chemical diversity in each sample, and unsupervised statistical methodologies provide key advantages to classify, authenticate, and highlight the potential presence of additives and adulterants.

Overview of Analytical Tools for the Identification of Adulterants in Commonly Traded Herbs and Spices.

Background: Spices and aromatic herbs have long been used by people to impart sensory appetizing elements, including aroma, flavor, and color, to foods and beverages in an effort to enhance their palatability. Herbs and spices exhibit a plethora of medicinal properties including antimicrobial and antioxidant properties. Spices serve as natural preservatives to delay food spoilage and extend shelf life. As spice trading has exponentially increased globally, herbs and spices have become prone to adulteration, which can be deliberate or unintentional. Deliberate adulteration is usually economically motivated, aimed at maximizing profit margins, whereas unintentional adulteration is often attributed to improper harvesting or processing of the plant material or collecting/substituting closely related species. Adulteration of herbs or spices with toxic ingredients such as Sudan dyes or metal salts (e.g., lead chromate) may result in serious public health consequences. Objective: To provide a concise account of ongoing adulteration issues with spices and herbs in order to enhance general awareness of the short- and longer-term implications of such fraud. Method: Last twenty-years of literature on various aspects of spice adulteration including text books and online resources were gathered and compiled. In addition, a number of original reports have been published prior to year 2000 that are directly associated with adulteration of commonly traded herbs and spices were also included. Results: The current review covers the role of spices and herbs in human life, adulteration of the commonly consumed spices and herbs, identification of their adulterants, as well as the most popular analytical techniques and methods used in their detection, including spectroscopic, chromatographic, electronic sensing, and deoxyribonucleic acid-based methodologies. Conclusions: Spices and herbs, being high-priced commodities, have been often subjected to adulteration in many ways which reduces their quality and potentially has harmful health implications. Adulteration is attributed primarily to increased demand or supply shortage of the spices and aromatic herbs. The motivation for spice fraud is largely attributed to economical interest to gain greater profit margins and such adulteration of spices can have serious implications for public health. To combat the adulteration of spices and herbs effectively, a range of analytical techniques across many different technologies have been developed. These techniques are expected to aid in the detection of adulterants and establish quantifiable concentrations for the compounds in question in various matrices, including spices and aromatic herbs.

Tackling Fraudsters with Global Strategies to Expose Fraud in the Food Chain.

Deliberate adulteration of food products is as old as food processing and production systems. Food adulteration is occurring increasingly often today. With globalization and complex distribution systems, adulteration may have a far-reaching impact and even adverse consequences on well-being. The means of the international community to confront and solve food fraud today are scattered and largely ineffective. A collective approach is needed to identify all stakeholders in the food supply chain, certify and qualify them, exclude those failing to meet applicable standards, and track food in a real time. This review provides some background into the drivers of fraudulent practices (economically motivated adulteration, food-industry perspectives, and consumers' perceptions of fraud) and discusses a wide range of the currently available technologies for detecting food adulteration followed by multivariate pattern recognition tools. Food chain integrity policies are discussed. Future directions in research, concerned not only with food adulterers but also with food safety and climate change, may be useful for researchers in developing interdisciplinary approaches to contemporary problems.

Quality Control of Krill Oil by Nuclear Magnetic Resonance (NMR) Spectroscopy: Composition and Detection of Foreign Species

ABSTRACTKrill oil is currently among the most highly promoted products in the dietary supplement market, which, due to its high price, can be potentially adulterated with fish species and artificial oil. For a holistic control of krill oil quality, 1H, 13C, and 31P nuclear magnetic resonance (NMR) spectroscopies were used. The fatty acid and phospholipid composition as well as secondary ingredients, such as homarine, amino acids, and chitin, were examined. The following phospholipid species were detected: phosphatidylcholine (75–85 mol %), phosphatidylethanolamine (4–7 mol%) and their lyso derivatives 1-lysophosphatidylcholine (1–2 mol%)–2-lysophosphatidylcholine (10–16 mol%) and lysophosphatidylethanolamine (1 mol%). In the -2 position of phospholipids, the content of eicosapentaenoic acid (mean 68.23%; relative standard deviation 2.23%) was twice as high as the content of docosahexaenoic acid (mean 31.77%; relative standard deviation 4.79%). 13C NMR spectroscopy was used to distinguish between krill and fish oil-based dietary supplements. The adulteration of krill oil can be detected by fatty acid distribution in the sn-2 triacylglycerol position. The sensitivity of the method is about 10% (w/w) of fish content in blends, which is enough to detect deliberate adulteration. The same methodology can be used to recognize synthetically modified krill oil. The method was successfully applied to 30 commercially available krill and fish oil supplements.

Revival of Complementary and Alternative Herbal Medicines

Herbal medicines, complementary or alternative medicines is a wide term for the therapies thatare not part of standard care but it has many theories regarding efficacy based on personal experiences, history and common knowledge. It has long been used since ancient times since the beginning of human civilization. Its use had caught much attention in the early 1800s, with the development in the science of chemistry, a new era in pharmacotherapeutics and the use of active chemical ingredients in plants which were known to produce favorable therapeutic effects, were explored, active compounds were extracted, purified and their structure was revealed. This advancement paved the way towards modern pharmaceutical therapy. The modern drugs are based on these herbal medicines, after extracting the active and pure chemical compounds. Pharmacokinetics and physicochemical properties of the active ingredients was explored. It lead to the better understanding of efficacy and safety profile of these drugs and first choice for treatment of various diseases. At the same time, the herbal medicines were considered as secondarily important.After approximately two centuries, the use of herbal medicines have seen a revival globally both indeveloping as well as developed countries. In the past few years, the practice of using herbal medicines as an alternative and complementary health medicine has gained more importance. Herbal medicines are common for treatment of various ailments including cancer, digestive disorders, pain related disorders, neuropathic ailments and cardiac arrhythmias etc. Even it has been used by pregnant females and mostly perceived as safe. Its use has gained more attraction due to its ‘natural’ approach and lesser side effects. Their use if often overlooked but physicians should pay attention to these medicines.There is lack of familiarity, standardization of the drug components, unproven therapeutic effectsin various diseases, unexplored toxicology, pharmacokinetics, drug-drug interactions, and compatibility in patients with varying medical, genetic and demographic history. There are serious concerns regarding the safety, efficacy and quality of herbal products and nutraceuticals. Accidental contamination and deliberate adulteration are assumed to be the main cause of the side effects.Much of the herbal medical knowledge is scattered in different regions of the world and mostlyavailable at family, community and local level and mostly in any native languages. There is need ofcoherent sources, knowledge, and exploration of these medicines across the world. The herbal medicine has varying diversity in different geological regions and they should be investigated. There should be a regional or national body to control and approve the herbal medicines. Proper documentations on these medicines and food supplements should also be done.

What’s in the box? Authentication of Echinacea herbal products using DNA metabarcoding and HPTLC

BackgroundDifferences in regulatory policies between countries as well as a lack of appropriate standardized methods for the authentication and quality control of herbal products directly impact their quality and safety. Echinacea products are among the top-selling herbal products in Europe and the United States with indications for a broad range of ailments. The increased use of Echinacea species has led to concerns about adulterated products resulting from challenges in morphology-based identification, due to overlapping morphological variation, frequent hybridization between species, and deliberate adulteration. PurposeThis study addressed the need for a novel analytical strategy in the authentication of herbal products. MethodsA combination of high performance thin layer chromatography (HPTLC) and DNA metabarcoding was employed. Fifty-three Echinacea herbal products marketed across Europe were tested to evaluate the accuracy of these methods in plant identification and their potential for detecting substitutes, adulterants and other unreported plant constituents. ResultsHPTLC provides high resolution in the detection of Echinacea phytochemical target compounds, but does not offer information on the other species within the product. Alternatively, we showed that the limitation of HPTLC in detecting non-targeted species can be overcome by the complementary use of DNA metabarcoding. Using DNA metabarcoding, Echinacea species were detected in 34 out of the 38 retained products (89%), but with a lack of discriminatory resolution at the species level due to the low level of molecular divergence within the Echinacea genus. All of the tested herbal products showed considerable discrepancies between ingredients listed on the label and the ones detected using DNA metabarcoding, registering an overall ingredient fidelity of only 43%. ConclusionThe results confirm that DNA metabarcoding can be used to test for the presence of Echinacea species and simultaneously to detect other species present in even highly processed and multi-ingredient herbal products.

Milking the Quality Test: Improving the Milk Supply Chain Under Competing Collection Intermediaries

We examine operational and incentive issues that conspire to reduce the quality of milk—via deliberate adulteration by milk farmers—acquired by competing collection intermediaries in developing countries. Broadly speaking, three main forces in the milk supply chain lead to the low quality of milk: high testing costs, harmful competition among stations, and free-riding among farmers. The goal of this study is to provide recommendations that address the quality problem with minimal testing. Interestingly, some intuitive interventions—such as providing stations with better infrastructure (e.g., storage and refrigeration facilities) or subsidizing testing costs—could hurt the quality of milk in the presence of competition. To save testing costs we utilize mixed testing, where the milk combined from multiple farmers is tested once. However, mixed testing makes the system vulnerable to free-riding among farmers. We counter free-riding by applying a credible threat of individual testing (although not its actual use in equilibrium). We then propose two interventions to combat the harmful competition among stations. The novelty of our proposals lies in utilizing the force of competition to solve a problem created by competition. The incentives in our proposals provide a new tool for the stations to compete and convert the harmful effect of competition (quality reduction) into a beneficial one (quality improvement), resulting in a socially desirable equilibrium outcome: all the farmers provide high-quality milk and each competing station conducts only one mixed test and no further testing. This paper was accepted by Serguei Netessine, operations management.

Adulteration and poor quality of Ginkgo biloba supplements

Adulteration of Ginkgo products sold as unregistered supplements within the very large market of Ginkgo products (reputedly £650 million annually) through the post-extraction addition of cheaper (e.g. buckwheat derived) rutin is suspected to allow sub-standard products to appear satisfactory to third parties, e.g. secondary buyers along the value chain or any regulatory authorities. This study was therefore carried out to identify products that did not conform to their label specification and may have been actively adulterated to enable access to the global markets.500MHz Bruker NMR spectroscopy instrumentation combined with Topspin version 3.2 and a CAMAG HPTLC system (HPTLC Association for the analysis of Ginkgo biloba leaf) were used to generate NMR spectra (focusing on the 6–8ppm region for analysis) and chromatograms, respectively.Out of the 35 samples of Ginkgo biloba analysed, 33 were found to contain elevated levels of rutin and/or quercetin, or low levels of Ginkgo metabolites when compared with the reference samples. Samples with disproportional levels of rutin or quercetin compared with other gingko metabolites are likely to be adulterated, either by accident or intentionally, and those samples with low or non-existent gingko metabolite content may have been produced using poor extraction techniques. Only two of the investigated samples were found to match with the High-Performance Thin-Layer Chromatography (HPTLC) fingerprint of the selected reference material. All others deviated significantly. One product contained a 5-hydroxytryptophan derivative, which is not a natural constituent of Ginkgo biloba.Overall, these examples either suggest a poor extraction technique or deliberate adulteration along the value chain. Investigating the ratio of different flavonoids e.g. quercetin and kaempferol using NMR spectroscopy and HPTLC will provide further evidence as to the degree and kind of adulteration of Gingko supplements. From a consumer perspective the equivalence in identity and overall quality of the products needs to be guaranteed for supplements too and not only for products produced according to a quality standard or pharmacopoeial monograph.