Survey of aflatoxin M1 in cheese from the North-east region of São Paulo,Brazil

In the present study, 24 samples of Minas Frescal cheese and 24 samples of Minas Padrão cheese produced in the North-east region of the state of São Paulo, Brazil, were analysed for aflatoxin M₁ (AFM₁) by high-performance liquid chromatography (HPLC) between March and August 2008. AFM₁ was detected in 13 (27.1%) samples at concentrations ranging from 0.037 to 0.313?ng?g^?1. The mean concentrations of AFM₁ in positive samples of Minas Frescal and Minas Padrão cheese were 0.142?±?0.118 and 0.118?±?0.054?ng?g^?1, respectively. It is concluded that the incidence of AFM₁ in Minas cheese may contribute to an increase in the overall ingestion of aflatoxins in the diet, hence indicating the need for the adoption of a tolerance limit for AFM₁ in cheese in Brazil.     

Coccidiostats in milk: development of a multi-residue method and transfer of salinomycin and lasalocid from contaminated feed

A confirmatory multi-residue method was developed for the determination in milk of 19 coccidiostats (amprolium, arprinocid, clazuril, clopidol, decoquinate, diclazuril, ethopabate, halofuginone, lasalocid, maduramicin, monensin, narasin, nicarbazin, nequinate, robenidine, salinomycin, semduramicin, toltrazuril sulfone and toltrazuril sulfoxide). Sample preparation utilising extraction with organic solvent and clean up by SPE and freezing was found reliable and time-efficient. Optimised chromatography and MS conditions with positive and negative ESI achieved sufficient sensitivity and selectivity. Validation experiments has proven method usefulness for routine analysis of coccidiostats in milk samples. An on-farm study conducted on dairy cows fed with experimentally contaminated feed with salinomycin and lasalocid showed negligible transfer to milk. No residues of lasalocid were found in collected samples. Salinomycin was found only in 5 of 168 samples analysed, while the concentrations of salinomycin in those samples (0.119–0.179 µg kg^–1) was significantly below the limit of salinomycin in milk set by European Union legislation. Such low concentrations of both coccidiostats cannot be explained by conjugation during dairy cows’ metabolism, as shown by experiments with enzymatic hydrolysis.     

The simultaneous determination of the ionophore antibiotics in animal tissues and eggs by tandem electrospray LC–MS–MS

A method has been developed for the simultaneous extraction and determination of the four most currently used Ionophore antibiotics (lasalocid, monensin, narasin and salinomycin) by LC–MS–MS from different animal tissues and eggs. Results show good repeatability, and mean spiked recoveries for lasalocid, monensin, narasin and salinomycin in animal livers are in the average range 93–103, 96–103, 93–102 and 97–106%, respectively, and in eggs the mean spiked recoveries are 101, 103, 98 and 102% for lasalocid, monensin, narasin and salinomycin, respectively. The detection limit is at 1 ng ml⁻¹ for all the named ionophorous compounds. A quantitation level of 50 ng g⁻¹ for lasalocid, monensin at 2.5 ng g⁻¹, and 10 ng g⁻¹ for narasin and salinomycin is achieved which represents half the action limit prescribed by the UK Regulation in compliance with the European Council Directive 96/23/EC. A high throughput of samples is achievable using this method which allows the analysis of 30–40 samples by one analyst in a day.     

Efficacy of bovicin HC5 and nisin combination against Listeria monocytogenes and Staphylococcus aureus in fresh cheese

Fresh and soft cheeses provide a suitable medium for the growth of many microorganisms and have been frequently associated with foodborne diseases. This study aimed to evaluate the effects of the bacteriocins bovicin HC5 and nisin on Listeria monocytogenes and Staphylococcus aureus in Minas Frescal cheese, a traditional Brazilian fresh product. The cheese was inoculated with 10⁴ CFU g^?1 of both pathogens, and the bacteriocins were added at 600 AU g^?1 of each one. After 9 days of storage at 4 °C, L. monocytogenes Scott A were not detected in 25 g samples. Although the bacteriocins reduced the population of S. aureus ATCC 6538, increasing numbers were detected after 15 days of storage at 4 °C. Staphylococcal enterotoxin C was detected in cheeses added of bacteriocins and stored under abusive temperature of 15 °C. The results demonstrate the potential application of combination of bovicin HC5 and nisin in controlling the pathogens growth assessed in Minas Frescal cheese.     

Metal levels in Trachurus trachurus and Cyprinus carpio in Turkey

Concentrations of five toxic metals were determined in two fish species from Turkish cities during 2010–2011. The obtained lead concentrations for all of the studied Trachurus trachurus (mean 777 μg kg^?1) and Cyprinus carpio (mean 439 μg kg^?1) samples were found to be higher than the maximum level (ML) of 300 μg kg^?1, while Cd concentrations in the same samples were lower than the ML. Mean chromium (501 μg kg^?1), Ni (272 μg kg^?1) and Cu (785 μg kg^?1) concentrations in T. trachurus were significantly higher than in C. carpio (336 μg Cr kg^?1, 229 μg Ni kg^?1 and 394 μg Cu kg^?1), similar to those of Pb and Cd. Measured Pb concentrations in T. trachurus tissues are significantly higher than the ML, while those of Cd in both T. trachurus and C. carpio species were lower than the ML values.     

3-Monochloro-1,2-propandiol (3-MCPD) in soy sauce from the Bulgarian market

The 3-monochloro-1,2-propandiol (3-MCPD) levels in soy sauces which contained hydrolysed vegetable protein were evaluated for the Bulgarian market. For analysis of 3-MCPD, a gas chromatography–mass spectrometry (GC-MS) method was applied with a linear range of 0.03–2.00 μg mL^?1 and a limit of detection (LOD) of 2.3 μg kg^?1 and a limit of quantification (LOQ) of 3.4 μg kg^?1. At these levels, the standard deviation was 5.1%, with recoveries between 81% and 102%. The method was applied to the analysis of 21 samples of soy sauce from the Bulgarian market. Results ranged from 3.7 to 185.6 μg kg^?1. Soy sauces produced from hydrolysed soy protein contained higher levels of 3-MCPD than naturally fermented sauces. In 38.4% of samples of Bulgarian origin, the 3-MCPD content was above the EU limit of 20 μg kg^?1. In all analysed samples, 33.3% had a 3-MCPD content above the EU limit.     

Development of a Headspace-Solid Phase Microextraction-Gas Chromatography/Mass Spectrometry (HS-SPME-GC/MS) Method for the Determination of Benzene in Soft Drinks

A method based on headspace-solid phase microextraction and gas chromatography with mass spectrometry has been developed and validated for the determination of benzene in soft drinks. The extraction step was optimized using a rotatable central composite design including the following experimental variables: extraction temperature, extraction time, sample weight, and salt concentration. The optimized procedure, which was carried out at 30 °C during 30 min by using a 75 μm carboxen-polydimethylsiloxane fiber, showed good linearity within the concentration range 0–25 μg?kg^?1 (r ² ?>?0.999), mean recoveries from 97.5 to 103.1 %, and coefficients of variation from 1.5 to 13.4 % for repeatability and from 1.5 to 15.7 % for within-laboratory reproducibility. Limits of detection and quantification were calculated at 0.02 and 0.08 μg?kg^?1, respectively. The method was applied to determine the concentrations of benzene in 77 samples of beverages from the Brazilian market. Levels from <0.08 to 10.84 μg?kg^?1 were obtained, which are comparable to those verified in other countries. Most of the samples (72.2 %) contained benzene up to 1 μg?kg^?1.     

Ultrasound-Assisted Extraction Followed by Solid-Phase Extraction Followed by Dispersive Liquid–Liquid Microextraction for the Sensitive Determination of Diazinon and Chlorpyrifos in Rice

Selectivity of solid-phase extraction (SPE) was combined with the concentration power of dispersive liquid–liquid microextraction (DLLME) to obtain a sensitive, low solvent consumption method for high-performance liquid chromatography determination of diazinon and chlorpyrifos in rice. In this method, rice samples were extracted by ultrasound-assisted extraction followed by SPE. Then, the SPE eluent was used as a disperser solvent in the next dispersive liquid-liquid microextraction step for further purification and enrichment of diazinon and chlorpyrifos. Under the optimal conditions, the linear range was from 5.0 to 250 μg kg^?1 for diazinon and from 2.5 to 250 μg kg^?1 for chlorpyrifos. Limits of detection of diazinon and chlorpyrifos were 1.5 and 0.7 μg kg^?1, respectively. Limits of quantitation of diazinon and chlorpyrifos were 5.5 and 3.0 μg kg^?1, respectively. The precisions and recoveries also were investigated by spiking 10 μg kg^?1 concentration in rice. The recoveries obtained were over 90 % with relative standard deviation (RSD%) below 9.0 %. The new approach was utilized to successfully detect trace amounts of diazinon and chlorpyrifos in different Iranian rice samples.     

Sodium benzoate and potassium sorbate preservatives in food stuffs in Iran

A high-performance liquid chromatography method was applied for the determination of the levels of benzoate and sorbate in 400 food samples, including pickled cucumbers, canned tomato pastes, sour cherry jams, soft drinks, fruit juices and dairy products (UF-Feta cheeses, Lighvan cheeses, lactic cheeses, yogurts and doogh). The results showed that 270 (67.5%) of all samples contained benzoate ranging from 11.9 to 288.5 mg kg^?1 in lactic cheese and fruit juice, respectively. The levels of sorbate in 98 (24.5%) of the samples were 20.1 to 284.3 mg kg^?1 in doogh and fruit juice, respectively. Moreover, benzoate was detected in all dairy products ranging from 11.9 mg kg^?1 in lactic cheese to 91.2 mg kg^?1 in UF-Feta cheese. A low concentration of benzoate could originate naturally, due to specific biochemical mechanisms during cheese, yogurt and doogh maturation. In conclusion, a minimum level for benzoate in dairy products should be defined in the legislation.     

p-Cresol in cheese: Is it a flavouring compound or chemical contaminant?

ABSTRACT

p-Cresol has been identified as a flavouring compound in cheeses; however, scientific studies have already identified p-cresol as a potential chemical contaminant in environmental matrices. Thus, the objective of this study was to evaluate four traditional methods for extracting p-cresol from cheese samples in order to validate the best method, and finally to apply it to five cheese samples with different origins, processing and ripeness times. The analyses were performed by gas chromatography-mass spectrometry after derivatisation of p-cresol with anhydride acetic and pyridine. Better results were achieved by the QuEChERS method, which showed recovery higher than 80%, relative standard deviation lower than 16%, limit of quantification of 5 μg kg^?1 and linearity between 5 and 400 μg kg^?1 with R² 0.99. p-Cresol was quantified in almost all of the samples analysed at different concentration levels, which were in an increasing order at μg kg^?1: Cheddar (< LOQ), Parmesan (8 ± 0.7), Gorgonzola (103 ± 14), smoked Provolone (365 ± 28) and barbecue cheese (1001 ± 187). Although no maximum residue limit has been established for p-cresol in food, the results suggest that cheeses exposed to charcoal combustion notably increase the p-cresol levels and may represent a hazard to human health, especially in risk groups such as patients with chronic kidney disease who have serious problems with p-cresol.     

Occurrence of patulin and 5-hydroxymethylfurfural in apple sour,which is a traditional product of Kastamonu,Turkey

Apple sour is a traditional product of Kastamonu, Turkey. It is consumed by spreading on bread or drinking after diluting with water. The aim of this study was to determine patulin (PAT) and 5-hydroxymethylfurfural (HMF) in apple sour. This study is the first to evaluate the occurrence of PAT and HMF in apple sour. The samples were extracted with ethyl acetate using liquid-liquid extraction technique. PAT and HMF were determined by HPLC with UV detection. PAT was detected in all samples, and the PAT level in 94.9% of samples was found to be equal or greater than the legal limit for juice concentrates. The mean value for PAT was found to be 284 ± 307 μg kg^?1. PAT levels in 13 of 39 samples were in the range of 100 ≤ x < 200 μg kg^?1, two samples were in the range of 0 ≤ x < 50 μg kg ?1 and two samples were in the range of 1000 ≤ x < 1500 μg kg¹. HMF levels of all samples were above the legal limit for solid molasses. The mean value for HMF was found to be 16215 ± 13317 mg kg^?1. HMF levels of 10 of 39 samples were determined to be in the range of 10000 ≤ x < 20000 mg kg^?1, eight samples were in the range of 20000 ≤ x < 30000 mg kg^?1 and only three samples were in the range of 100 ≤ x < 1000 mg kg^?1. There was a significant and inverse relationship between HMF and pH of the samples. These results indicate that consumption of apple sour is a considerable risk in terms of HMF and PAT toxicity.     

Occurrence of glyphosate in beer from the Latvian market

A sensitive LC-MS/MS method for the determination of glyphosate in beer has been developed, validated, and applied to analyse 100 beer samples from 24 different producers and distributors in Latvia. The selected samples represented most beer brands and varieties sold in local supermarkets. Different procedures for sample preparation and chromatographic separation were compared. The final version of the method consisted of solid phase extraction, chromatographic separation on aminopropyl stationary phase, and detection using tandem mass spectrometry. The concentration of glyphosate in beer varied from below the LOD of 0.2 μg kg^?1 up to 150 μg kg^?1, higher than previously reported. Significantly higher (p < 0.01) content of glyphosate was observed in beers that did not have the country of production disclosed on the label and were sold in local supermarkets by distributors from Latvia (1.8 μg kg^?1 median concentration in locally produced beer, 6.7 μg kg^?1 in beer of undisclosed origin).     

Co-occurrence of aflatoxins,ochratoxin A and citrinin in “egusi” melon (Colocynthis citrullus L.) seeds consumed in Ireland and the United Kingdom

The natural co-occurrence of aflatoxins (AFs), ochratoxin A (OTA) and citrinin (CIT) in melon seed samples obtained from retailers and households in Ireland and the United Kingdom (UK) was evaluated. AFs and OTA were determined by HPLC with fluorescence detection while CIT was analysed by HPLC-MS/MS. AFB₁ was detected in all (100%) samples (mean = 9.7 μg kg^?1; range = 0.2–66.5 μg kg^?1). Mean total AFs was 12.0 μg kg^?1 (range = 0.3–82 μg kg^?1). Commercially retailed samples showed a significantly higher AFB₁ contamination (p < 0.05) than the household samples. OTA occurred in 3 (13.6%) samples, while 4 (18.2%) were contaminated with CIT at very low levels. In this study, 68% of the melon seed samples were contaminated above the 2 μg kg^?1 EU limit for AFB₁ in oilseeds. These results highlight the need for the development of strategies to reduce AF contamination in “egusi” for human consumption.     

Aflatoxins and ochratoxin A in flour: a survey of the Serbian retail market

This report presents data on the occurrence of aflatoxins (AF) and ochratoxin A in different types of flour marketed in Serbia. A total of 114 samples of wheat, buckwheat, rye, oat, barley, rice, millet and corn flour were collected in the period 2012–2016 and analysed using high performance liquid chromatography with fluorescence detection. Among flours other than corn, AFB1 was quantified only in rice, while ochratoxin A (OTA) was found in 29% of the samples. In corn flours the percentage of positive samples varied greatly over the years: AFB1 7.1–80.0%, OTA 30.0–40.6%, with a co-occurrence of 7.1–34.4%. Overall 5.2% of flours other than corn and 10.7% of corn flours exceeded the maximum levels (MLs) for AFB1 and/or OTA. The highest recorded levels were 8.80 μg kg^?1 of AFB1 (corn) and 23.04 μg kg^?1 of OTA (rye). Overall mean contamination levels of corn flours were 0.53 μg kg^?1 of AFB1 and 0.46 μg kg^?1 of OTA.     

Determination of glyphosate,AMPA, and glufosinate in honey by online solid-phase extraction-liquid chromatography-tandem mass spectrometry

A simple method was developed for the simultaneous determination of glyphosate, its main degradation product (aminomethylphosphonic acid), and glufosinate in honey. Aqueous honey solutions were derivatised offline prior to direct analysis of the target analytes using online solid-phase extraction coupled to liquid chromatography-tandem mass spectrometry. Using the developed procedure, accuracies ranging from 95.2% to 105.3% were observed for all analytes at fortification levels of 5, 50, and 150 μg kg^?1 with intra-day precisions ranging from 1.6% to 7.2%. The limit of quantitation (LOQ) was 1 μg kg^?1 for each analyte. Two hundred honey samples were analysed for the three analytes with AMPA and glyphosate being most frequently detected (99.0% and 98.5% of samples tested, respectively). The concentrations of glyphosate were found to range from <1 to 49.8 μg kg^?1 while those of its degradation product ranged from <1 to 50.1 μg kg^?1. The ratio of glyphosate to AMPA was found to vary significantly amongst the samples where both analytes were present above the LOQ. Glufosinate was detected in 125 of 200 samples up to a maximum concentration of 33.0 μg kg^?1.     

Evaluation of short chain chlorinated paraffins in human milk and their intake by infants in Hebei Province,China

ABSTRACT

Short-chain chlorinated paraffins (SCCPs) have drawn increasing interest worldwide since they were included in the list of controlled persistent organic pollutants in Annex A of the Stockholm Convention in 2017, and the potential health risk they pose to humans must be evaluated. In this study, 86 human milk samples were collected from 55 healthy Chinese mothers living in the Shijiazhuang region of Northern China in 2014–2015. Advanced online gel permeation chromatography–gas-chromatography-coupled mass spectrometry with negative-ion chemical ionisation was used to quantify the SCCPs in the samples. The estimated mean level of SCCPs was 2.51 μg g^?1 lipid weight (range 0.21–16.12). The SCCP concentration correlated positively with the mother’s bodyweight at the end of pregnancy (P < 0.05). The mean SCCP intake by infants via breast milk was 13.0 μg kg^?1 day^?1 at 1 month, 7.1 μg kg^?1 day^?1 at 3 months, and 2.5 μg kg^?1 day^?1 at 6 months after birth. This study provides initial data on the levels of SCCPs in human milk in a chlorinated-paraffin-manufacturing area in China, and indicates a high health risk for infants.     

Aflatoxin M1 in raw milk from different regions of São Paulo state – Brazil

A total of 635 raw milk samples from 45 dairy farms, from three regions of São Paulo state – Brazil, were evaluated during 15 months for aflatoxin M₁ (AFM₁). AFM₁ was determined by high performance liquid chromatograph with fluorescence detection. AFM₁ was detected (>0.003 µg kg^?1) in 72.9%, 56.3% and 27.5% of the samples from Bauru, Araçatuba and Vale do Paraíba regions, respectively. The mean AFM₁ contamination considering all the samples was 0.021 µg kg^?1. Furthermore, the concentration of AFM₁ was quite different among Bauru (0.038 µg kg^?1), Araçatuba (0.017 µg kg^?1) and Vale do Paraíba (<0.01 µg kg^?1) regions. Only three samples (0.5%) had higher contamination than the tolerated limit in Brazil (0.50 µg kg^?1) and 64 samples (10.1%) had a higher contamination than the maximum limit as set by the European Union (0.050 µg kg^?1). The estimated AFM₁ daily intake was 0.358 and 0.120 ng kg^?1 body weight per day for children and adults, respectively.     

Ochratoxin A in red pepper flakes commercialised in Turkey

The aim of this study was to investigate the presence of Ochratoxin A (OTA) in red pepper flakes commercialised in Turkey. A total of 75 samples were collected from different supermarkets and traditional bazaars in Istanbul during 2012–2013. OTA analysis was performed by high-performance liquid chromatography equipped with fluorescence detection after immunoaffinity column clean-up. The method was linear in the range 0.05–40 μg kg^?1 (r² = 0.9997). Twenty-seven out of 31 (87.1%) packed red pepper flake samples contained OTA at concentrations ranging from 0.6 to 1.0 μg kg^?1, whereas 100% of the unpacked red pepper flake samples contained OTA, in the range 1.1–31.7 μg kg^?1. Overall, only 4 unpacked samples (5.3%) contained OTA, with a mean value of 23.4 μg kg^?1, which is higher than the European Union limit. It is suggested that OTA content should be carefully considered in red pepper flake samples especially marketed in unpacked form.     

Occurrence of bound 3-monochloropropan-1,2-diol content in commonly consumed foods in Hong Kong analysed by enzymatic hydrolysis and GC-MS detection

The aim of this study was to determine the level of bound 3-monochloropropan-1,2-diol in foodstuffs commonly consumed in Hong Kong, China, by an enzymatic hydrolysis indirect method which proved to be free from interferences. A total of 290 samples were picked up randomly from the local market and analysed. About 73% of these samples were found to contain detectable amounts of bound 3-MCPD. Amongst the 73 food items, bound 3-MCPD was not detected in 13 food items, including extra virgin olive oil, beef ball/salami, beef flank, ham/Chinese ham, nuts, seeds, soy sauce, oyster sauce, butter, yoghurt, cream, cheese and milk. For those found to contain detectable bound 3-MCPD, the content ranged up to 2500 µg kg^?1. The highest mean bound 3-MCPD content among the 14 food groups was in biscuits (440 [50–860] µg kg^?1), followed by fats and oils (390 [n.d.–2500] µg kg^?1), snacks (270 [9–1000] µg kg^?1), and Chinese pastry (270 [n.d.–1200] µg kg^?1). Among the samples, the highest bound 3-MCPD content was in a grape seed oil (2500 µg kg^?1), followed by a walnut flaky pastry (1200 µg kg^?1) and a grilled corn (1000 µg kg^?1). Basically, the results of this study agreed well with other published results in peer-reviewed journals, except for cheese, cream, ham, nuts and seeds.