Determination of heavy metals in selected black sea fish species

Heavy metals can be accumulated by marine organisms thought a variety of pathways, including respiration, adsorption and ingestion. The levels of heavy metals are known to increase drastically in marine environment through mainly anthropogenic activities. Fish are good indicators for the long term monitoring of metal accumulation in the marine environment. The aim of this study was to determine the levels of Cd, As, Hg, Pb, Zn and Cu in edible part and gill of seven most consumed Bulgarian fish species collected from north-east coast of Black Sea. These fish species are sprat (Sprattus sprattus sulinus), Mediterranean horse mackerel (Trachurus mediterraneus ponticus), Black sea gobies (Neogobius melanostromus), shad (Alosa pontica), Atlantic bonito (Sarda sarda), bluefish (Pomatomus saltatrix) and grey mullet (Mugil cephalus). The fish samples were collected during 2010. The analytical determination of As, Cd, Pb, Zn and Cu were performed by using flame and graphite furnace atomic absorption spectrometry after microwave digestion procedure. The total mercury determination was determined using a direct mercury analyzer (DMA-80). The metal concentration of analyzed elements was highest in the gill for all fish species. The maximum metal concentration was measured for Cu (1.40 mg kg⁻¹ w.w), Zn (11 mg kg⁻¹ w.w) and Pb (0.08 mg kg⁻¹ w.w) in muscle tissues of shad and sprat. The edible part of horse mackerel has the maximum value for Hg (0.12 mg kg⁻¹ w.w) while Atlantic bonito predominantly accumulates As (1.10 mg kg⁻¹ w.w). The analytical results obtained from this study were compared within acceptable limits for human consumption set by various health institutions.     

Scope extension validation of a LC-MS method for the inspection of preservatives in butter

Butters are considered as “natural products” by many consumers, once they are obtained from milkfat without adding of any additive, except sodium chloride, starter cultures and natural dyes. The main goals of this study were to extend the scope of a previously developed method, including a new analyte (benzoic acid) and new matrices (butter and margarine), and thus evaluate the content of preservatives in national and imported butters traded in Brazil. Samples (n = 51) from inspected establishments in Argentina (n = 2), Brazil (n = 40), France (n = 7) and Uruguay (n = 2) were assessed by liquid chromatography-tandem mass spectrometry. Two screening inspection rounds were carried out between November, 2015 and January, 2016. Non-compliance rates were 36.4% in 2015 and 22.2% in 2016 for Brazilian butters. It was shown that preservatives are irregularly added to butters by many factories, contrary to regulation, and without proper declaration on labeling. The limits of quantitation (LOQ) were set to 25.00 mg kg⁻¹ (benzoic acid), 1.25 mg kg⁻¹ (natamycin), 3.13 mg kg⁻¹ (nisin) and 2.50 mg kg⁻¹ (sorbic acid). Except nisin, any of the researched preservatives was detected in a total of 12 samples, in concentrations that ranged from <LOQ–235.67 mg kg⁻¹ (benzoic acid), 8.26–35.60 mg kg⁻¹ (natamycin) and 4.52–1007.17 mg kg⁻¹ (sorbic acid). The method was also checked on margarine samples, revealing concentrations that ranged from 43.72 to 359.17 mg kg⁻¹ (benzoic acid) and from 509.00 to 1102.67 mg kg⁻¹ (sorbic acid), respectively. Our findings demonstrate that there is a need for stricter control in butter processing, with the aim to ensure food safety and to safeguard consumers.     

Contamination levels for lead,cadmium and mercury in marine gastropods,echinoderms and tunicates

As part of a specific monitoring programme, total lead (Pb), cadmium (Cd) and mercury (Hg) concentrations in marine gastropods (common winkle, common whelk, abalone and murex), echinoderms (purple sea urchin and black sea cucumber) and tunicates (an ascidian species) were investigated by the French National Reference Laboratory (NRL) for trace elements in foodstuffs of animal origin. These elements were analysed by atomic absorption spectrometry in order to evaluate the safety of these species for human consumption. The highest levels of Hg and Cd were found in murexes, 0.185 mg kg^?1 and 0.853 mg kg^?1, respectively; whereas the highest level of Pb was detected in ascidians (0.505 mg kg^?1). Hg and Pb concentrations were always below the maximum levels set by the European legislation (0.5 mg Hg kg^?1 and 1.5 mg Pb kg^?1 wet mass) and for Cd, only 2 samples of murex (2.09 ± 0.42 mg kg^?1 and 2.33 ± 0.46 mg kg^?1) exceeded the maximum level set by French legislation of 2.0 mg kg^?1 wet mass.     

Sushi commercialized in Brazil: Organic Hg levels and exposure intake evaluation

The presence of organic mercury (methylmercury) in tuna, salmon and kani sushis marketed in restaurants specialising in Japanese foods (Campinas, São Paulo, Brazil), was investigated by atomic absorption spectrometer with thermal decomposition and amalgamation. Total mercury was analyzed directly, whilst organic mercury was quantified after a previous extraction with toluene in an acid solution, assisted by microwaves. Under these analytical conditions there was no interconversion between the inorganic and organic mercury. High sensitivity was observed for organic mercury, with limits of detection and quantification of 2.0 and 6.6 μg kg⁻¹. The organic mercury contents ranged from 12 to 583 μg kg⁻¹, 6.6 to 8.2 μg kg⁻¹ and no detected values, for the tuna, kani and salmon sushi, respectively. The mean proportion of organic Hg/total Hg for tuna sushi was 88%, indicating that the most toxic form of mercury, organic Hg, predominate in this food. The estimated exposure to methylmercury was made by taking into account the Provisional Tolerable Weekly Intake (PTWI 1.6 μg/kg) considering the daily consumption of 150 g and 20 g per adults (60 kg) and children (15 kg), respectively. Our results demonstrated that the consumption of tuna sushi may exceed 100% of PTWI.     

Characterization and selection of Lactobacillus brevis starter for nitrite degradation of Chinese pickle

To improve the safety of Chinese pickles, lactic acid bacteria were isolated from traditional fermented foods to test for nitrite degradation during the pickling process. Lactobacillus brevis AR123 was screened out as a starter culture for pickle fermentation. L. brevis AR123 has a high tolerance to nitrite and salt. During pickle fermentation, the nitrite peak appeared from 12 to 24 h in the pickle juice and was delayed to 24–48 h in the pickles. In 6% salt, L. brevis AR123 and a commercial starter could rapidly lower the pH of the pickles, and the nitrite contents were 0.83 mg kg⁻¹ and 3.05 mg kg⁻¹, respectively, in pickles at 72 h. Meanwhile, no obvious nitrite peak was observed for the pickle inoculated with a mixed starter; it had a low nitrite level (0.88 mg kg⁻¹ at 72 h). However, the concentration of nitrite was as high as 17.92 mg kg⁻¹ in the spontaneous fermentation group. During pickle fermentation, Lactic acid bacteria (LAB) population increased significantly when salt concentration was 4%–8%, and sensory analysis shown that the L. brevis AR123 inoculated pickle exhibited better sensory evaluation results than spontaneous fermentation pickle. In conclusion, inoculation with L. brevis AR123 alone or combined with a commercial starter (mixed starter) is effective in removing nitrites and enhancing the sensory properties of pickle. LAB could accelerate degradation of nitrite significantly and shorten the fermentation time for pickle process.     

Occurrence of four mycotoxins in cereal and oil products in Yangtze Delta region of China and their food safety risks

A total of 76 cereal and oil products collected from Yangtze Delta region of China were analyzed for occurrences of aflatoxins (AFs), aflatoxin B₁ (AFB₁), ochratoxin A (OTA), deoxynivalenol (DON) and zearalenone (ZEN). The mycotoxins were determined by the standard detection procedures using immunoaffinity column clean-up coupled with fluorometer (or HPLC-UV). ZEN was the most prevalent toxin, with the incidence of 27.6% (range = 10.0–440.0 μg kg⁻¹), and 9.2% of the evaluated samples were contaminated with a concentration higher than that of the legislation limit of China (60 μg kg⁻¹). AFs and AFB₁ were detected in 14.5% of the samples analyzed, the concentrations ranging 1.1–35.0 μg kg⁻¹ for AFs, and 1.0–32.2 μg kg⁻¹ for AFB₁; 4.0% of the samples had the concentrations of AFs and AFB₁ higher than that of the corresponding legislation limits of China (5.0, 10.0 and 20.0 μg kg⁻¹ for different products). OTA was detected in 14.5% of the cereal and oil products collected; the concentrations ranged 0.51–16.2 μg kg⁻¹. Only 2 samples showed OTA levels higher than that of the legislation limit of China (5.0 μg kg⁻¹). DON was detected in 7.9% of the samples; the concentrations ranged 100–700 μg kg⁻¹, and none of the samples showed DON concentration higher than that of the legislation limit of China (1.0 mg kg⁻¹). A total of 15.8% cereal and oil products were contaminated with at least two mycotoxins (multiple contaminations with different combinations including AFs-ZEN, AFs-OTA-ZEN, OTA-ZEN, ZEN-DON, OTA-ZEN-DON). The dietary exposure assessment results indicated that AFs (AFB₁), OTA, DON and ZEN from cereal-based products represented a series health risk to both adults and children in Yangtze Delta region of China. This is the first report of safety evaluation associated with major mycotoxins for the area.     

Chlorpyrifos residue levels on field crops (rice,maize and soybean) in China and their dietary risks to consumers

In this study, chlorpyrifos residue levels in field crops of rice, maize and soybean were investigated according to the “Guideline on Pesticide Residue Trials” of China. On the basis of the residual results, human dietary risks were further evaluated. Chlorpyrifos residues of harvest grains were firstly prepared by QuEChERS method and analyzed using Gas Chromatography Tandem Mass Spectrometry (GC–MS/MS). Dietary risks were assessed by a deterministic approach. The median residues in field trials of rice, maize and soybean were 0.617, 0.0227 and 0.0136 mg kg⁻¹, respectively. The highest residues in field trials of rice, maize and soybean were 3.23, 0.114 and 0.102 mg kg⁻¹, respectively. Chronic intake assessment indicated that only 39.0% of acceptable daily intake (ADI, 0–0.01 mg kg bw⁻¹ day⁻¹) was consumed through rice, maize and soybean. The acute hazard indexes (aHI) of adults was 26.1% of acute reference dose (ARfD, 0–0.1 mg kg bw⁻¹) and aHI of children was 63.5% of ARfD in dietary exposure assessment through rice, maize and soybean consumption. Single pathway risk assessment indicated that chlorpyrifos application on field crops in manner of the good agricultural practices didn't pose public health risks.     

Determination of Cd in food using an electrothermal vaporization capacitively coupled plasma microtorch optical emission microspectrometer: Compliance with European legislation and comparison with graphite furnace atomic absorption spectrometry

A precise, accurate and sensitive method based on electrothermal vaporization capacitively coupled plasma microtorch optical emission spectrometry for Cd determination in various dietary products was developed. The instrumentation is inexpensive as it includes a low power (15 W) and low argon consumption (150 ml min⁻¹) microplasma connected to a small-sized Rh electrothermal vaporization device and a low resolution microspectrometer. The sample was subjected to microwave assisted digestion in HNO₃ – H₂O₂ mixture and Cd was determined in 10 μl sample without preconcentration. The standard addition method was used to compensate for the non-spectral matrix effects. The new method was in-house validated by analyzing certified reference materials and test dietary samples for which the Cd maximum level was established in Commission Regulation 488/2014/EU. The figures of merit of the proposed method and the experimental results were compared to those obtained in graphite furnace atomic absorption spectrometry as standardized method and discussed in relation with the requirements in the Commission Decision 2002/657/EC and Commission Regulations 2011/836/EU and 2007/333/EC. The limit of detection in fresh sample (0.001–0.009 mg kg⁻¹), limit of quantification (0.002–0.018 mg kg⁻¹), recovery (103 ± 15%), trueness (−3.0)–(+7.3)% and precision (0.8–14.0%) were similar to those found in the reference method and comply with the minimal criteria imposed to a method to be used in official laboratories for Cd determination in food. Precision for Cd determination close to maximum admitted levels or higher was of 0.8–6.0%, while for lower concentration in the range 4.0–14.0%. The Bland and Altman statistical test allowed successful evaluation of the new method as an alternative to the well established graphite-furnace atomic absorption spectrometry. The proposed method has analytical potential and is easy to run, while the full miniaturized instrumentation could be considered as a useful tool for the future as an alternative to the traditional instrumentation.     

Development and validation of a new qualitative ELISA screening for multiresidue detection of sulfonamides in food and feed

An indirect competitive enzyme-linked immunosorbent assay (ELISA) to screen sulfonamide residues in food (muscle, eggs, milk and honey) and feed has been developed and validated according to Commission Decision 2002/657/EC. The immunoreagents were appropriately produced to detect a wide range of sulfonamide antibiotic congeners, obtaining half-maximum inhibition concentration (IC₅₀) values below 10 μg L⁻¹ for 11 sulfonamides widely used in veterinary practices. Taking into account the complexity of involved matrices, specific sample preparation protocols have been optimised combining high method throughput with low detectable concentrations. Accordingly, depending on the congener, the obtained detection capabilities (CCβs) were lower or equal to 20 μg kg⁻¹ (muscle, eggs and milk), 10 μg kg⁻¹ (honey) and 2 mg kg⁻¹ (feed). Finally the developed qualitative test was applied to real samples collected within the official monitoring programmes: results exceeding the established screening cut-off were re-analysed with a suitable confirmatory method. The presence of one or more sulfonamides was found in all the suspect screening samples thus demonstrating that the proposed ELISA can be successfully applied in class-specific detection of sulfonamides in food and feed.     

Application of solid phase extraction and two-dimensional gas chromatography coupled with time-of-flight mass spectrometry for fast analysis of polycyclic aromatic hydrocarbons in vegetable oils

A fast and simple solid-phase extraction (SPE) method followed by comprehensive two-dimensional gas chromatography coupled to time-of-flight mass spectrometry (GC × GC–TOFMS) has been developed for analysis of 15 + 1 carcinogenic polycyclic aromatic hydrocarbons (PAHs) in vegetable oils. Of three critically assessed sample preparation approaches – (i) gel permeation chromatography (GPC), (ii) GPC followed by silica based SPE, and (iii) SPE employing PAHs-dedicated molecularly imprinted polymers (MIPs), the latter one was selected as the best option. Recoveries of the overall analytical procedure ranged from 70 to 99%, with repeatabilities in the range of 2–11%. Limits of quantitation (LOQs) ranging for individual PAHs from 0.1 to 0.3 μg kg⁻¹, were fairly below the maximum level 2 μg kg⁻¹ established for the PAHs representative, benzo[a]pyrene (BaP), by EU Legislation for this commodity. Within the mini-survey in which the new method was employed for examination of 35 samples of various kinds of vegetable oils collected at the Czech market, the highest PAH4 levels, i.e. the sum of BaP, benz[a]anthracene (BaA), benzo[b]fluoranthene (BbFA) and chrysene (CHR) were found in sea buckthorn (708 μg kg⁻¹) followed by rapeseed oil (99.8 μg kg⁻¹). Altogether 8 samples from 35 examined vegetable oils exceeded the maximum limit 2 μg kg⁻¹ for BaP and 10 samples exceeded 10 μg kg⁻¹ set for PAH4 which is fixed by Commission Regulation (EU) no 835/2011 for oils.     

A survey study on safety and microbial quality of “gluten-free” products made in Italian pasta factories

The rising prevalence of celiac disease leads to an increased demand of “gluten-free” products. A survey study on the gluten content and on the microbiological quality of “gluten-free” flour, and processing flour products, was carried out from 2010 to 2015 in Northern Italy. Overall 12,419 samples were analyzed, and 94.7% contained a gluten concentration less than 5 mg kg⁻¹ (lower limit of detection). Only 0.1% of samples showed a gluten concentration above 80 mg kg⁻¹ (maximum limit of detection). In the remaining 5.2%, the gluten concentration was between 5 and 80 mg kg⁻¹, underlining how a gluten-free diet completely devoid of gluten is unrealistic. The microbiological quality of these products was investigated.Overall, the majority of samples revealed microbial loads of less than 1 l g CFU g⁻¹ (lower limit of detection). High levels of spoilage bacteria were found in egg-containing products. Total mesophilic bacteria were counted in all analyzed food categories with concentrations up to about 6, 8 and 9 l g CFU g⁻¹ in dry pasta, flours and egg products respectively. Listeria monocytogenes was found only in one sample, whereas Salmonella spp. was never found.Buckwheat flour was the most frequently contaminated product by presumptive Bacillus cereus, with a prevalence of 12.5%. Also, a contamination by Coagulase-Positive Staphylococci was found during this investigation, especially in buckwheat dry pasta and flour and in egg dry pasta, with a prevalence of 54.7%.This study aimed to enhance the knowledge about the “gluten-free” products which are still poorly studied, even if their impact on the food market is increasingly considerable.     

Evaluation of mercury,cadmium and lead levels in fish and fishery products imported by air in North Italy from extra-European Union Countries

The levels of cadmium (Cd), mercury (Hg) and lead (Pb) were evaluated in 251 samples of fish and fishery products randomly collected between January 2010 and December 2013 from products imported through the airport of Milan Malpensa from extra-European Union (extra-EU) Countries and inspected at the Border Inspection Post by official public veterinarians. In this study, products were classified in four categories: predatory fish (larger predatory fishes like tunafish and swordfish, and spiny dogfish), non-predatory fish (other species of fishes of lower dimensions and different feeding behavior, mollusc (cephalopods and bivalves) and crustacean). Analyses were performed by accredited laboratory. All the concentrations were below the levels expressed in Regulation (EC) No 1881/2006 except for two samples of swordfish that exceeded in Hg content. Predatory fish had a significantly higher content of Hg (median value 375 μg kg⁻¹) while mollusc had a significantly higher content of Cd (median value 66.5 μg kg⁻¹) compared to the other groups of seafood included in this study. No relationship was found between the individual concentration of metals.     

Saturated aqueous ozone degradation of deoxynivalenol and its application in contaminated grains

Deoxynivalenol (DON) is a secondary metabolite produced by Fusarium graminearum in grains, food and contaminated feed, which can lead to many adverse health effects to humans and livestock. The degradation of DON in different contaminated grains oxidated by saturated aqueous ozone (80 mg L⁻¹) was monitored by ultra-high-performance liquid chromatography, tandem-quadrupole-detection mass spectrometry (UPLC–TQD-MS). Results suggest that ozone has a significant effect on DON reduction in solution. When 80 mg L⁻¹ gaseous ozone was used to treat 10 mg L⁻¹ of DON solution, the degradation rate of DON reached 83% within 7 min, while the respective detoxification rates of contaminated wheat, corn and bran by saturated aqueous ozone (80 mg L⁻¹) were 74.86%, 70.65% and 76.21 in 10 min. Ozone at 80 mg L⁻¹ was applied on various DON solution concentrations at 1 mg L⁻¹, 10 mg L⁻¹ and 20 mg L⁻¹ in ultra-pure water. In this paper, the degradation procedure for DON is calculated and described by a first-order kinetic equation. At lower levels (20 mg L⁻¹) of aqueous ozone, intermediate degradation products were observed by ultra-ne quickly and effectively degrades DON and toxicity in various contaminated grains in a matter of minutes. Therefore, ozonation is projected to be an effective, fast, and safe method for DON degradation.     

Should chlorate residues be of concern in fresh-cut salads?

Chlorine remains the most popular method used by the fresh produce industry for decontamination. However, the occurrence of disinfection by-products (DBP) derived from chlorine-based disinfectants has been highlighted as a problem. After recent reports, chlorate residues in fresh produce are of concern in Europe. This study evaluated the chlorate accumulation in process wash water and the residues in fresh-cut lettuce when sodium hypochlorite was used as a wash aid. At a commercial processing facility, total chlorine was continually added to achieve a free chlorine level of 1–80 mg L⁻¹ for water disinfection as the organic load measured as chemical oxygen demand (COD) increased over time (1000–1500 mg O₂ L⁻¹). This resulted in chlorate accumulation (19–45 mg L⁻¹) in the process water. When fresh-cut lettuce was washed in that water, chlorate residues were detected in the lettuce and the concentrations increased linearly with the repeated use of the same process water, reaching concentrations of 4.5–5.0 mg kg⁻¹. To understand the chlorate accumulation in the process wash water, several experiments were performed at a pilot plant scale with different levels of COD and free chlorine. There was a significant (p < 0.001) correlation (R = 0.91) between the total added chlorine and the chlorate accumulation in the process water. We demonstrated that the added chlorine needed to maintain a free chlorine level in the process water was the contributing factor to chlorate accumulation. Chlorate residues in the washed fresh-cut lettuce after rinsing for 1 min in tap water and in commercial bags were below the limit of quantification. This study contributes to the knowledge of chlorate accumulation in the process water when sodium hypochlorite was used as a sanitizer.     

Effect of ozone treatment on aflatoxin B1 and safety evaluation of ozonized corn

This paper studies the ozone treatment effect on degradation of aflatoxin B₁ (AFB₁) in corn with different moisture content (MC). The toxicity of the degradation products (DPs) of the ozone-treated AFB₁-Contaminated Corn (ACC) was also evaluated using the human hepatocellular carcinoma cell line (HepG2) as model cells. The degradation rate of AFB₁ in corn increases with ozone concentration and treatment time. The results showed that ACC with 13.47% MC was easier to be degraded by ozone than with 20.37% MC. Treated with 90 mg L⁻¹ ozone for 20 min and 40 min, AFB₁ in corn with 13.47% MC decreased from 83 μg kg⁻¹ to 18.12 μg kg⁻¹ and 9.9 μg kg⁻¹, respectively, well meeting the China National Standard of AFB₁ in corn (20 μg kg⁻¹). In order to evaluate the safety of ozone used on ACC, the impacts of AFB₁ as well as untreated and ozone-treated ACC with the same level of AFB₁ content on HepG2's survival rate, morphology, and apoptosis were studied. The results showed that ACC had high cell toxicity while the toxicity of ozone-treated ACC had no significant difference with that of the AFB₁-free culture solution. It is concluded that ozonation can quickly and effectively degrade AFB₁ in corn and diminish ACC's toxicity, and therefore, ozonation is expected to be an effective, fast, and safe method for AFB₁ degradation in ACC.     

Detection and monitoring of 3-monochloropropane-1,2-diol (3-MCPD) esters in cooking oils

A series of refined palm oil products were collected from different refineries in Malaysia and were analysed for 3-MCPD esters content. Samples were analysed using acidic transesterification and quantification by Gas Chromatography-Mass Selective Detector (GC-MSD). This method is based on the Federal German Institute for Risk Assessment (BfR) Method 008 for 3-MCPD esters. Limit of Detection (LOD) for this method was 0.25 mg kg⁻¹ and Limit of Quantification (LOQ) was 0.50 mg kg⁻¹ 3-MCPD esters were generally not detected in crude oils, but were found at trace levels in bleached oils. Deodorized or fully refined oils contained higher 3-MCPD esters. The values ranged from <0.25-5.77 mg kg⁻¹ for palm oil products, whilst other cooking oils in the retail ranged from <0.25-2.45 mg kg⁻¹.     

Rapid method based on immunoassay for determination of paraquat residues in wheat,barley and potato

The detection of bipyridine herbicides residues in food samples is hampered due to their particular physico-chemical features, which requires the application of specific extraction and analytical procedures, which disqualifies them from being incorporated into the multi-residue methods (MRMs). There is a need for alternative robust and efficient analytical screening methods, and in this respect, we present here a fast and reliable immunochemical analytical procedure for the detection of paraquat (PQ) residues in food samples, particularly potato, barley and wheat. The procedure involves the extraction with 1 N HCl:MeOH at 80 °C, followed by centrifugation and filtration, and the extracts can be directly measured by a microplate-based ELISA without any other sample treatment or clean-up, except from buffering the solution and adjusting the pH. Selective polyclonal antibodies, were raised against N-(4-carboxypent-1-yl)-N′-methyl bipyridilium acid (hapten PQ1), and used to establish a high sensitive immunochemical analytical assay, able to measure simultaneously many samples. Under these conditions the accuracy is very good, with almost quantitative recoveries. The non-specific interferences caused by the matrix are negligible for the case of potato and wheat, while for barley it is necessary to further dilute the extract or using a negative certified extract to build the standard calibration curve. The method of extraction consisted in acidic extraction and after a dilution is able to be measured. The analysis method results simply, achieving good detectabilities. The limits of detection (LODs) achieved were between 0.037 ± 0.01 μg kg⁻¹ in wheat, 0.71 ± 0.3 μg kg⁻¹ in barley and 0.56 ± 0.10 μg kg⁻¹ in potatoes, values that are far below the Maximum Residue Level (20 μg kg⁻¹) established by the EU policies for paraquat residues in these foodstuff products. The results demonstrate the high potential of these methods as screening tools for food safety and inspection controls.     

A survey of mycotoxins in random street-vended snacks from Lagos,Nigeria, using QuEChERS-HPLC-MS/MS

A survey in African snacks was carried out in order to evaluate the intake of 23 mycotoxins. The African snack samples were purchased from street vendors within Lagos metropolis (Nigeria) and evaluated for the presence of 23 mycotoxins using a modified QuEChERS procedure coupled with liquid chromatography-triple quadrupole linear ion trap mass spectrometer. The snacks included akara, baked coconut, coconut candy, donkwa, groundnut cake (kulikuli), lafun, milk curd (wara), fresh and dried tiger-nuts, and yam flour. Only three mycotoxins were detected in 23.8% of the studied snacks, and at concentrations ranging from 6 to 54 μg kg⁻¹. The concentrations of aflatoxin B₁ (AFB₁) and AFB₂ reached 23 μg kg⁻¹ and 3 μg kg⁻¹, respectively. Moreover a sample of baked coconut contained α-zearalenol (α-ZOL), which was up to 54 μg kg⁻¹ in coconut candy. As considers prevalence, aflatoxins and α-ZOL were not detected in lafun and groundnut-based snacks (donkwa and kulikuli), whereas each of the three mycotoxins contaminated 12.5% (1/8) of the coconut-based samples. This is the first report of α-ZOL in cassava and coconut, and their products. AFB₁ and total aflatoxins (TAFs) concentrations exceeded the maximum allowable limit recommended by National Agency for Food and Drug Administration and Control Nigeria (NAFDAC) in one sample of baked coconut (AFB₁ = 23 μg kg⁻¹ and TAFs = 26 μg kg⁻¹) and donkwa (AFB₁ = 19 μg kg⁻¹ and TAFs = 21 μg kg⁻¹).     

Aflatoxins and ochratoxin A in dried eggplant and green bell pepper

In this study, 50 dried eggplant and 50 dried green bell pepper samples were analyzed in terms of their aflatoxin and ochratoxin A (OTA) content. Aflatoxins G₂, G₁, B₂, and B₁, and OTA contents were analyzed using high-performance liquid chromatography with a flame ionization detector (HPLC–FID). Total aflatoxin and, as well as aflatoxin G₂, G₁, B₂, and B₁ content in dried eggplant samples were ranged between 0.82 and 2.58, 0.10–0.23, 0.32–1.35, 0.12–0.67, and 0.17–0.71 μg kg⁻¹, respectively. Total aflatoxin and, as well as aflatoxin G₂, G₁, B₂ and B₁ content in dried green bell pepper samples were 0.81–2.42, 0.11–0.22, 0.32–1.38, 0.13–0.66, and 0.18–0.91 μg kg⁻¹, respectively. OTA content was varied from 8.88 to 21.35 μg kg⁻¹ in eggplant samples, and from 15.38 to 24.70 μg kg⁻¹ in dried green bell pepper samples. Of the dried eggplant samples and dried green bell pepper samples, 36% and 24% of them, respectively, had aflatoxin B₁ values which were below the minimum limit of detection (LOD) of 0.05 μg kg⁻¹. None of the analyzed samples exceeded the legal limit values of 10 μg kg⁻¹ for total aflatoxin content, and 5 μg kg⁻¹ for aflatoxin B₁ content. However, 80% of the dried eggplant samples and 100% of the dried green bell pepper samples exceeded the legal limit value for OTA content (15 μg kg⁻¹). According to the results, it was concluded that dried vegetables should be examined in terms of their aflatoxins. It is essential to analyze OTA content more thoroughly, as it has the potential to pose a risk for public health, as well as for the economy.     

The efficacy of grape seed extract,citric acid and lactic acid on the inactivation of Vibrio parahaemolyticus in shucked oysters

The efficacy of grape seed extract (GE), citric acid (CA) or lactic acid (LA) on the inactivation of Vibrio parahaemolyticus in shucked oysters was studied. The minimum inhibitory concentration (MIC) of GE, CA or LA against V. parahaemolyticus in TSB-1% NaCl was also determined. The shucked oysters were artificially inoculated with V. parahaemolyticus, the inoculated shucked oysters (25 g) were then dipped in solution of GE (0.0, 10.0, 20.0, 50.0, 100, 200, 300 and 500 mg mL⁻¹), CA (0.0, 5.0, 10.0, 15.0, 20.0, 50.0, 100, 200 and 300 mg mL⁻¹) or LA (0.0, 1.0, 5.0, 10.0, 15.0, 20.0, 50.0, 100 and 150 mg mL⁻¹) for 10 min. The population of V. parahaemolyticus in shucked oysters was determined. The MICs of GE, CA or LA against V. parahaemolyticus were 10.0, 5.0 or 1.0 mg mL⁻¹, respectively. A 500, 300 or 150 mg mL⁻¹ GE, CA or LA solutions were needed to reduce the population of V. parahaemolyticus to below the detection level (1.0 log g⁻¹) in shucked oysters.