Indirect enzyme‐linked Immunosorbent assay for detection of cow's milk in goat's milk

An indirect enzyme‐linked immunosorbent assay (ELISA) has been developed for the specific detection of cow's milk (1–25%) in goat's milk. The test uses polyclonal antibodies raised in rabbits against bovine whey proteins (BWP). The anti‐BWP antibodies were recovered from the crude antiserum by immunoadsorption and elution from a column containing immobilized BWP. The anti‐BWP antibodies were biotinylated and rendered cow's milk specific by mixing them with lyophilized ovine and caprine whey proteins. Streptavidin‐peroxidase was used to detect the biotinylated anti‐BWP antibodies bound to bovine milk proteins immobilized on 96‐well plates. The colour developed by the subsequent enzymic conversion of the substrate gave clear absorbance differences when assaying mixtures of goat's milk containing variable amounts of cow's milk.     

Quinine drinking: More regulatory puzzles

Rats were permanently hypodipsic when offered a quinine adulterated fluid on a chronic basis. Plasma osmolarity and Na concentration were normal, but the quinine drinkers showed a slight hyperkalemia compared to water drinking controls. The quinine-drinking rats maintained hydromineral equilibrium through the excretion of a small amount of concentrated urine. The quinine intake was closely matched to need, and fell to near zero when food was removed or water was supplied intravenously. This harmony of intake and output was disrupted after acute hypertonic NaCl load: while the obligatory salt diuresis was no different between water and quinine drinkers, the latter did not drink (except at the lowest level of adulteration) within several hours. However, by 24 hr all had shown a delayed drinking response. This delay in drinking of quinine was also evident after non-painful intravenous NaCl infusions, but no drinking occurred after nephrectomy. Quinine drinkers were also unresponsive to isoproterenol and intracranial dipsogens. These data are discussed in terms of their implication for definitions of regulatory drinking behavior.     

纸基-表面增强拉曼光谱法快速鉴别染色南五味子药材

目的 采用纸基-表面增强拉曼光谱法(SERS)对染色南五味子进行快速鉴别。方法 选用浸泡法制备的银胶纸作为SERS基底,擦拭经乙醇-水溶液润湿的南五味子,银胶纸立即进行SERS检测;先后对银溶胶的浓缩倍数、银胶纸的SERS增强效果及稳定性等因素进行考察。结果 成功鉴别低浓度酸性红、赤藓红染色的南五味子。结论 纸基-SERS法可实现非法染色南五味子的快速、准确、无损的鉴别,有望应用于快检领域。     

Direct metabolic fingerprinting of olive oils using STELDI-MS

A new and rapid approach for analysis of olive oil has been developed using sorptive tape-like extraction in combination with laser desorption ionization mass spectrometry (STELDI-MS). This powerful combination has some great advantages, as no-separation steps, solvent-free, matrix-free, and no sample preparation. The olive oil compounds are analyzed by LDI-MS, directly from the sample spot in a thin-layer chromatography (TLC) plate. Chosen samples represent products commonly used as adulterants in extra virgin olive oil (EVOO) and the main monitored ions were lipid adulteration markers. Analytical procedures consisted of profiling the main fatty acids (m/z 255 – palmitic acid, 279 – linoleic acid, 281 – oleic acid and 283 – stearic acid), triacylglycerols (m/z 901 – LLL and 907 – OOO) and some phenolic compounds (m/z 169 – gallic acid, 193 – ferulic acid and 195 – 2(4-hydroxyphenyl) ethyl acetate) in extra virgin olive oil (EVOO), olive oil (OO), hazelnut oil (HO) and soybean oil (SO). Compound identification was confirmed by analysis of collision-induced dissociation (CID) products in positive (ion [M+Na]⁺) and negative mode (ion [M−H]⁻). This method is simple, fast and efficient in identifying compounds that can be used to recognize different levels of adulteration, oxidation and hydrolysis of vegetables oils.     

Adulterants in selected dietary supplements and their detection methods

At present, there is a growing trend toward the intentional adulteration of dietary supplements (DS) with synthetic pharmaceuticals, which represents an alarming emerging risk to consumers and a serious problem for regulatory agencies. An amazing array of synthetic drugs and their analogues have been reported as adulterants in DS. Mainly, the presence of analogues represents a serious health risk as their efficacy and toxic effects have not been clinically assessed yet and may result in unpredictable adverse effects. The purpose of this review is to provide an overview, over the period 2009–2019, of the most frequently reported adulterants in DS for the treatment of erectile dysfunction, obesity/overweight, diabetes mellitus, and hypertension and the analytical methods used for their detection.     

Hygienic quality,adulteration of pork and histamine production by Raoultella ornithinolytica in milkfish dumpling

Ten milkfish dumpling products purchased from retail stores in southern Taiwan were collected to determine the occurrence of biogenic amines, histamine-forming bacteria, and adulteration of pork. This study showed the high contents of aerobic plate count (APC), total coliforms (TC) and Escherichia coli in tested milkfish dumpling samples, whereas the average content of various biogenic amines in all tested samples was < 1.6 mg/100 g (< 0.05 to 1.54 mg/100 g). Three histamine-producing bacterial strains (2 isolates of Raoultella ornithinolytica and 1 isolate of Enterobacter aerogenes) isolated from tested samples produced 276.6 ppm to 561.8 ppm of histamine in trypticase soy broth supplemented with 1.0% L-histidine (TSBH). Assay of multiplex polymerase chain reaction (PCR) revealed that the adulteration rates were 50% (5/10) for pork in milkfish dumplings. In addition, milkfish dumpling stuffing was inoculated with R. ornithinolytica at 5.0 log colony forming units (CFU)/g and stored at various temperatures from 4°C to 37°C to investigate bacterial growth and formation of histamine. The histamine contents quickly increased to higher than 50 mg/100 g in samples stored at 37°C and 25°C within 24 hours and 36 hours, respectively, as well as stored at 15°C within 48 hours. Therefore, bacterial growth and histamine formation were controlled by cold storage of the samples at 4°C.     

丁香掺杂染色问题及检测方法研究

目的：4-甲基咪唑为焦糖色素制备过程中的一副产物,通过建立4-甲基咪唑的快速检测方法,控制丁香中花梗染焦糖色素后掺入样品。方法：采用高效液相色谱-质谱联用法,色谱柱为PhenomenexLuna C18（2 mm×150 mm,3μm）,以甲醇-0.1%甲酸溶液为流动相梯度洗脱,流速0.3 mL·min^-1,柱温30℃;质谱使用电喷雾离子源,正离子模式下检测。结果：4-甲基咪唑在9.28~371.11 ng·mL^-1浓度范围内呈良好的线性关系（r=0.9994）,平均回收率96.91%,RSD=1.0%;160批次丁香中33批次检出4-甲基咪唑,表明上述样品涉嫌染色。结论：本方法快速、简便、准确,专属性强,灵敏度高,可作为丁香中4-甲基咪唑的定性定量检测方法,为控制丁香质量提供参考。     

TLC-SERS联用法检测降糖中成药中添加的格列类药品

目的：研究降糖中成药中非法添加格列类药品的表面增强拉曼光谱（ surface enhanced Raman spectroscopy , SERS）检测方法。方法利用薄层色谱法将待检成分与中药基质进行简单分离,采用表面增强拉曼光谱技术对薄层板上的微量物质进行检测。通过摸索模拟阳性样品中格列类药品的SERS检测条件,建立可用于降糖中成药中非法添加物的检测方法。结果采用有机溶剂DMF制备所得的银溶胶可以获得较好的格列类药物SERS图谱。结论该研究所建立的TLC与SERS联用方法检测简便、快速、经济,可用于降糖中成药中非法添加格列类药品的快速检测。     

Urinary melamine: Proposed parameter of melamine adulteration of food

Melamine is widely being reported as a food adulterant. Although its toxicity is currently recognized, melamine adulterations of food items are ongoing for falsely inflating the protein content of the food. Melamine alone or in combination with cyanuric acid or uric acid causes nephrotoxicity, and melamine-induced nephrotoxicity is now a global concern. It has been proven that when consumed, melamine is metabolized at a slower rate and excreted unchanged in urine. There is every possibility that when individuals consume melamine-adulterated food items, the melamine may be excreted unchanged in the urine. Therefore, melamine estimation in urine may be a yardstick to check for melamine adulteration of food items. In the present review, recent literature on this subject is analyzed justifying.     

Adulteration of Chinese herbal medicines with synthetic drugs: a systematic review

The popularity of Chinese herbal medicines (CHMs) demands a critical analysis of safety issues. The aim of this systematic review is to summarize data regarding adulterations of CHMs with conventional drugs. Literature searches were carried out in six databases. Articles containing original data on adulterations were considered without language restrictions. Eighteen case reports, two case series and four analytical investigations were identified. The list of adulterants contains drugs associated with serious adverse effects like corticosteroids. In several instances, patients were seriously harmed. One report from Taiwan suggests that 24% of all samples were contaminated with at least one conventional pharmacological compound. It is concluded that adulteration of CHMs with synthetic drugs is a potentially serious problem which needs to be addressed by adequate regulatory measures.