Journal of AOAC International最新文献

Background: Freshness is one of the most important qualities of fish and has a significant impact on utilization and commercial value. As global production and trade volumes of fishery products increase, standardization of scientific methods for evaluating fish freshness is required.

Objective: The K value based on the ratio of ATP derivative content is widely recognized as a scientific freshness index of fish. The aim of this study was to standardize the K value analysis method, which would be useful for fair commercial transactions of bony fish.

Methods: Conventional methods for analyzing K values of fish were modified. An interlaboratory study was conducted to evaluate the reproducibility of the method. The 11 participating laboratories analyzed 10 test samples (five pairs of blind duplicates of material) using HPLC.

Results: For five test materials with a K value of 6.12-83.4%, the range of reproducibility relative standard deviation (RSDR) was 1.3-3.5%. The reproducibility standard deviation (sR) was 0.21-1.2%.

Conclusion: Considering the rate of increase of K value in typical bony fish species and storage conditions, the target value of sR was set to ≤1.25%, so detecting a difference of 5% in K values. The results of the interlaboratory study met this criterion.

Highlights: The precision of the method was found to be acceptable.

Background: Glucose is the most abundant monosaccharide. Glucose is mainly made by plants during photosynthesis from water and carbon dioxide, using energy from sunlight. It is therefore contained in many foodstuffs naturally or added later as an ingredient.

Objective: To validate the performance of the Enzytec™ Liquid D-Glucose for the determination of D-glucose in food and beverages such as fruit and vegetable juices, soft drinks, wines, and beer.

Methods: The kit contains two ready-to-use components, which makes handling easy and suitable for automation. D-Glucose is phosphorylated to glucose-6-phosphate (G-6-P) by a hexokinase and ATP. In the presence of glucose-6-phosphate dehydrogenase and NAD, G-6-P reacts to gluconate-6-phosphate, whereby NADH is formed and measured at a wavelength of 340 nm within 20 minutes.

Results: Mannose and D-fructose interfere at 5.1 and 12.5 g/L (or more), respectively. Sulfite does not interfere up to 1.25 g/L. The calculated LOD and LOQ when using a test solution volume of 100 µL are 1.4 and 4 mg/L, respectively. The linear measurement range is from 4 to 2000 mg/L D-glucose. Trueness was checked by using materials from NIST (cranberry juice) and one reference wine from the German Wine Analysts. Spiking of wine, beer, and juices resulted in recoveries between 93 and 101%. Analysis of NIST SRM 3282 resulted in an intermediate precision of 4.1%. For automation, three applications with different test solution volumes and different but overlapping measurement ranges were validated. Linearity is given from 2.4 up to 10 000 mg/L.

Conclusions: The method is robust and accurate for manual and automated applications. The method was approved as AOAC Official Method of Analysis℠.

Highlights: The ready-to-use components of the test kit have a shelf life of at least 29 months from the date of manufacture.

Background: Miquelianin (MIQ) is a natural phenolic compound found in various plants, including Salvia species, with potential health benefits due to its antioxidant and anti-inflammatory properties.

Objective: This study presents an investigation of the electrochemical oxidation pathway and sensitive analysis of MIQ, which was isolated from the aerial parts of Calystegia silvatica (CS) that grows in Trabzon, Turkey.

Methods: Electrochemical determination methods have gained significant attention for the quantitative analysis of bioactive compounds due to their simplicity, sensitivity, and cost-effectiveness. The electrochemical determination of MIQ primarily involves the utilization of electrochemical techniques such as cyclic voltammetry (CV) and differential pulse voltammetry (DPV).

Results: Under optimum experimental conditions, a calibration plot for MIQ with LODs of 99.3 × 10-9 M and 145 × 10-9 M were obtained using DPV with glassy carbon electrodes (GCEs) and boron-doped diamond electrodes (BDDEs) in the range of 2.0 × 10-6 to 3.6 × 10-5 M. The presented method was validated and successfully performed for the determination of MIQ from plant extracts with excellent recovery values as 104.7, 101.8, and 102.1%.

Conclusion: This study explores the electrochemical oxidation pathway and sensitive analysis of MIQ, isolated from C. silvatica in Trabzon, Turkey. GCEs and BDDEs as carbon-based electrodes were used for the sensitive analysis of MIQ in phosphate buffer (PB) solution at pH 7.0 solution. MIQ was detected using GCEs and BDDEs with limits of 99.3 × 10-9 M and 145 × 10-9 M, respectively, within a concentration range of 2.0 × 10-6 to 3.6 × 10-5 M. The validated method demonstrated excellent recovery values of 104.7, 101.8, and 102.1% for determining MIQ from plant extracts.

Highlights: This electrochemical method offers promising opportunities for accurate and sensitive analysis of MIQ. Continued research and technological advancements in this field can contribute to a deeper understanding of the electrochemical behavior of MIQ and facilitate its practical applications in pharmaceutical, food, and nutraceutical industries, promoting its utilization as a valuable bioactive compound.

Background: Selenoneine exhibits antioxidant properties and is thus expected to become a new functional ingredient. Accurately determining selenoneine levels in foods is therefore critical.

Objective: This study investigated and validated extraction methods for selenoneine in seafood and seafood-derived products.

Methods: Selenoneine was extracted from seafood and seafood-derived products by sonication for 1 h and incubation at 37 °C for 24 h in a solution of 50 mmol/L dithiothreitol (DTT). The concentration of selenoneine was then determined using liquid chromatography-inductively coupled plasma mass spectrometry (LC-ICP-MS) and size-exclusion column chromatography using a mobile phase of 0.1 mmol/L ammonium acetate with 0.1% IGEPAL®.

Results: The method was validated using a DTT solution that effectively extracts selenoneine. The LOD (0.020-0.030 mg/kg), LOQ (0.067-0.099 mg/kg), repeatability (3.4-8.9%), intermediate precision (4.1-8.9%), and trueness (recovery of 94-109% based on spiked samples) of the proposed method were satisfactory for determining selenoneine in seafood and seafood-derived products. Selenoneine was detected in migratory fish and processed migratory fish products obtained in Japan. Particularly large amounts of selenoneine were detected in the dark muscle of bluefin tuna.

Conclusion: Using a reagent reactive to thiol groups, selenoneine was effectively extracted from seafood and seafood-derived products. The results of method validation analyses were satisfactory. Selenoneine was detected in processed products prepared from migratory fish, indicating that selenoneine remains even after processing. Water-soluble selenoneine was found to be extracted in the liquid.

Highlights: Selenoneine could be effectively extracted using DTT, and determination of selenoneine in various seafood was possible using LC-ICP-MS.

Background: The Bacillus cereus group (B. cereus sensu lato) is a group of spore-forming strains. B. cereus group is a human pathogen associated with foodborne outbreaks with symptoms of diarrhea and emesis.

Objective: This study evaluates the performance of BACARA® 2 (BAC2) and RAPID'B. cereus® (RAPID) agars compared to mannitol-egg yolk-polymyxin (MYP) agars and the original BACARA® (BAC) media to detect and enumerate the B. cereus group in pure culture and foods.

Methods: We incorporated five food types to include liquid milk, whey powder, mashed potatoes, rice, and tea bags. For each food matrix, there were five test portions per level inoculum prepared (low, medium, and high), and a negative control. Individual test portions were diluted 1:10 in Butterfield's phosphate buffer (BPB) and 0.1 mL of the dilutions were inoculated on BAC2, RAPID, and MYP agars. In-house R script was applied to conduct statistical analysis to compare medium performance in food adulteration tests.

Results: Inclusivity testing determined that all six B. cytotoxicus strains grew on BAC2, RAPID, and MYP but only one strain grew on BAC after 24 h incubation. RAPID had similar results as BAC2 in single-colony tests. In food tests, relative level of detection (RLOD) values indicated MYP was more sensitive for detecting B. cereus strains than BAC2 and RAPID, which is a result of B. cytotoxicus strains in mashed potato and whey powder needing an additional 24-hour incubation to exhibit typical morphology on BAC2 and RAPID.

Conclusion: Our study demonstrated the use of BAC2 and/or RAPID agar will improve the performance of the U.S. Food and Drug Administration Bacteriological Analytical Manual (BAM) B. cereus method, particularly for the detection of B. cytotoxicus. Importantly, the use of BAC2 and/or RAPID will decrease the time to detect viable B. cereus strains without additional confirmation steps compared to MYP.

Highlights: For improved isolation and identification of B. cereus group in foods, we propose the use of BAC2 or RAPID as optional agars, along with MYP.

Background: Ivermectin (IVM) is commonly used for the treatment of parasitic diseases in aquaculture and is administered either through oral or immersion methods, but it lacks regulatory approval.

Objective: The aim of the present study was to determine the acute oral toxicity of IVM by estimating the 96 h median lethal dose (LD50) using mortality as endpoint, for an economically important freshwater fish, Cyprinus carpio.

Methods: Medicated feed was prepared by employing different doses of IVM top-dressed onto the commercial feed pellets. A single oral dose of IVM at different doses (mg/kg b.wt.) of 0 (control-T1), 1 (T2), 2.5 (T3), 5 (T4), 10 (T5), 12 (T6), 15 (T7), 18 (T8), 21 (T9), 25 (T10), and 50 (T11) was dissolved in dimethyl sulfoxide (DMSO) and top-dressed using 0.5% w/v guar gum as a wet binder to the feed. The medicated feed was administered at 3% b.wt. to all treatment groups and cumulative mortalities were recorded over a duration of 96 h.

Results: The estimated LD50 of IVM was found to be 8.91 ± 3.46 mg/kg·b.wt. Furthermore, the treatment group (T2) was administered a single oral dose of 1 mg/kg b.wt. and did not exhibit any noticeable behavioral changes compared to the control group. Similarly, LOAEL and NOEAL doses were found to be 2.5 mg/kg b.wt. and 1 mg/kg b.wt., respectively.

Conclusions: This study provides valuable insights for further determining the safe dosage of IVM that can be used in aquaculture for the treatment of parasitic diseases.

Highlights: The present study might be helpful for fixing the maximum residual limit (MRL) for IVM in the aquaculture sector, and the data will be helpful for prescription of the drug by regulatory authorities for treating parasitic diseases in fish.

Background: The Petricore™ Aerobic Count (AC) method is used for enumeration of mesophilic bacterial colony counts in a broad range of food and environmental samples. The plate is a ready-to-use dry rehydratable film media composed of modified standard-method nutrients, water-soluble gelling agents and a tetrazolium indicator on the adhesive sheets, and transparent cover film.

Objective: The purpose of this study is to validate the Petricore AC for AOAC Performance Tested MethodsSM (PTM) certification.

Methods: Matrix studies were conducted on a broad range of foods and select environmental samples: fresh raw ground beef, fresh raw ground pork, raw bacon, raw shrimp, raw salmon, frozen raw tuna, frozen sliced mushrooms, frozen avocado, frozen blueberries, bacon-lettuce-tomato sandwich, frozen pizza (margherita), cooked sausage (fish and chicken breast), Romaine lettuce, cabbage, fresh green juice, stainless steel surface, plastic surface, and lettuce wash water. Petricore AC results were compared to standard-method plating procedure results appropriate to each matrix type. Product consistency and stability testing was performed on three production lots of Petricore AC, and robustness experiments examined the allowable range of three parameters: culture temperature, incubation time, and inoculum amount.

Results: In the matrix study, equivalent results were observed between the Petricore AC method and reference methods for all matrixes evaluated. The mean log10 differences between candidate method and reference methods were within the ranged from -0.23 to 0.35 log10 within the acceptable range of -0.50 to 0.50 log10. The range of standard deviation values of the candidate method (0.01-0.88 log10) and the reference method (0.02-0.91 log10) were similar in all matrixes evaluated. The range of correlation factor R2 was between 0.9539 and 0.9981, indicating strong correlation between the two methods. In the product consistency/stability study, the Petricore AC plate was proven to be equivalent across production lots, and the shelf life was established at 1 year. Small differences in method parameters did not affect the Petricore AC results in robustness testing.

Conclusion: The Petricore AC plate is an accurate method for the enumeration of mesophilic aerobic bacteria in the matrixes evaluated.

Highlights: The data were reviewed by the AOAC PTM Program and approval was granted for certification of Petricore AC as PTM 032502.

Background: The increasing popularity of herbal medicines and dietary supplements has raised concern about potential adulteration with pharmaceutical drugs.

Objective: To detect and determine cyproheptadine (CYP) and dexamethasone (DEX) as adulterants in weight gain herbal supplements found in the Iraqi market.

Methods: Nine herbal supplements marketed as natural weight gainers were purchased from local pharmacies and were screened using high-performance liquid chromatography (HPLC) for qualitative and quantitative detection of CYP and DEX.

Results: CYP was detected in seven of the nine products at levels of 2.65-8.6 mg per dosage unit. DEX was detected in all test solutions at levels of 6.2-18.75 mg per dosage unit.

Conclusion: A large proportion of herbal weight gain supplements was found to contain undeclared pharmaceuticals with severe health implications. The findings call for the immediate institution of tighter regulatory control and regular quality control tests in the name of consumer safety.

Highlights: Herbals and supplements for weight gain are increasingly popular but may be adulterated with pharmaceutical drugs that impose serious health risks for consumers. There is an urgent need for regulatory enforcement and routine quality checks are recommended.

Background: It is a common practice to process crude turmeric (CT) using different approaches; however, limited research is available on the comparison of volatile organic compounds (VOCs) before and after processing.

Objective: This study investigated the impact of five different processing methods on the VOCs of CT before and after processing.

Method: The five types of processed turmeric included vinegar-treated turmeric (VT), mussel powder-treated turmeric (MT), water extract of rice-processed turmeric (RT), stir-fried turmeric (ST), and wine-processed turmeric (WT). The gas chromatography-mass spectrometry (GC-MS) technique was used to identify the volatile profiles. Volatilomics based on multivariate statistics was used to assess the key metabolic differences between these five types of processed turmeric and CT within the VOCs.

Results: A total of 79 VOCs were detected between processed turmeric and CT, with terpenoids accounting for most of them. In the ST and WT groups, compared to the CT group, the number of changes in VOCs was relatively small, whereas in the VT, RT, and MT groups, there were a greater number of changes, with most metabolites exhibiting a downward trend. Through the volatilomics analysis, 13 potential differential compounds were screened out, among which there were three common differential compounds.

Conclusions: This study reveals the primary causes for the variations in VOCs in processed turmeric and CT, establishing the groundwork for evaluating the overall quality of processed turmeric and its use in therapeutic settings.

Highlights: The study systematically compared the effects of five different turmeric processing methods on VOCs using GC-MS-based volatilomics, providing a data reference for research on the changes in its pharmacological activity.

Background: D- and L-lactic acid are produced naturally by lactic acid bacteria and are found in fermented milk products, pickled vegetables, and cured meats. D-lactic acid is formed by some microorganisms only, e.g., Lactobacillus lactis and Leuconostoc cremoris. D-Lactic acid is not formed or only in traces by "higher organisms," e.g., by animals. Therefore, the presence of D-lactate may serve as an indicator for microbial contamination or spoilage, assuming that fermentation techniques have not been used.

Objective: To validate the performance of the Enzytec™ Liquid D-Lactic acid for the determination of D-lactic acid in food and beverages such as milk and (fermented) milk products, fermented vegetable products, wines, beer, fruit and vegetable juices, and eggs and egg powder.

Methods: The kit contains two ready-to-use components, which makes handling easy and suitable for automation. D-lactic acids react in the presence of NAD and D-lactate dehydrogenase to pyruvate and NADH. The NADH formed is equivalent to the amount of D-lactic acid converted.

Results: Ascorbic acid, 3-hydroxybutyric acid, and sulfite interfere at concentrations higher than 0.2, 0.2, and 0.05 g/L, respectively. Oxaloacetic acid, pyruvic acid, and D-fructose do not interfere at or below concentrations of 0.2, 1, and 10 g/L, respectively. The calculated LOD when using a test volume of 100 µL is 5.4 mg/L, and the LOQ is 15 mg/L. The practical upper measurement range is 600 mg/L. Relative intermediate precision was between 3.5 and 5.7% for pineapple juice, sauerkraut juice, wine, and liquid egg. A reference material (wine) showed recoveries of 108%. For automation, three applications with different test volumes were validated. Linearity is given from 0.75 up to 3125 mg/L.

Conclusions: The method is robust and accurate and was approved as an AOAC Official Method of Analysis℠.

Highlights: The ready-to-use components of the test kit have a shelf life of at least 24 months.