Leafy Vegetable Samples Research Articles

Antibiotic-resistant bacteria contaminating leafy vegetables in Saudi Arabia’s eastern region

BackgroundFood-associated antibiotic-resistant bacteria can cause infections that may critically impact human health. The objectives of this study were to determine the microbial contamination level of green leafy vegetables and their antibiotic resistance pattern.MethodsSixty-three samples of leafy vegetables were collected from Dammam Central Fruit and Vegetables Market from January to June 2023. The vegetables included lettuce (Lactuca sativa), parsley (Petroselinum crispum), and watercress (Nasturtium officinale). Samples were tested by standard microbiological techniques for identification and antibiotic susceptibility testing.ResultEight types of bacteria belonging to six different genera were detected. Enterobacteriaceae family was represented by four genera: Klebsiella, Proteus, Morganella, and Enterobacter. The other two genera were Pseudomonas and Aeromonas. Enterobacter cloacae was the most abundant organism, followed by Pseudomonas putida and Aeromonas sobria. On the other hand, Morganella morganii, Aeromonas hydrophila, and Proteus mirabilis were the least abundant. The three vegetable types had different levels of bacterial contamination. All isolated organisms were sensitive to penicillin, cephalosporin, aminoglycoside, and fluoroquinolone. However, Klebsiella oxytoca, M. morganii, and K. pneumonia showed resistance to ampicillin. A. hydrophila, Morganella morganii, and E. cloacae showed resistance to amoxicillin. M. morganii and E. cloacae were found to be resistant to cefalotin. Moreover, A. hydrophila, M. morganii, and E. cloacae were resistant to cefoxitin. Again, A. hydrophila was found to be resistant to imipenem. Only M. morganii was resistant to Ciprofloxacin. Two isolates, P. mirabilis and M. morganii were resistant to tigecycline. Another two, M. morganii and P. mirabilis were resistant to Nitrofurantoin. Only M. morganii was found to be resistant to trimethoprim.ConclusionThis study aligns with the broad consensus in the literature about the significance of bacterial contamination in vegetables and the public health implications. The unique focus on antibiotic resistance patterns adds an essential dimension to the existing body of knowledge.

Uptake of tire-derived compounds in leafy vegetables and implications for human dietary exposure

IntroductionTire and road wear particles are one of the most abundant types of microplastic entering the environment. The toxicity of tire and road wear particles has been linked to their organic additives and associated transformation products. Tire and road wear particles, and associated tire-derived compounds are introduced to the agricultural environment via atmospheric deposition, irrigation with reclaimed wastewater, and the use of biosolids (treated sewage sludge) as fertilizer. In the agricultural environment, these tire-derived compounds could be taken up by edible plants, leading to human exposure.MethodsSixteen tire-derived compounds were measured in twenty-eight commercial leafy vegetable samples from four countries. Based on the results, the estimated daily intake of these tire-derived compounds was calculated due to leafy vegetable consumption based on local diets under a mean and maximum concentration scenario.ResultsIn commercial leafy vegetables, six tire-derived compounds were detected: benzothiazole (maximum concentration—238 ng/g dry weight), 2-hydroxybenzothiazole (maximum concentration—665 ng/g dry weight), 1,3-diphenylguanidine (maximum concentration—2.1 ng/g dry weight), N-(1,3-dimethylbutyl)-N′-phenyl-p-phenylenediamine (6PPD, maximum concentration—0.4 ng/g dry weight), N-Isopropyl-N-phenyl-4-phenylenediamine (IPPD, maximum concentration—0.1 ng/g dry weight), and N-phenyl-N-cyclohexyl-p-phenylenediamine (CPPD, maximum concentration—0.3 ng/g dry weight). At least one compound was present in 71% of samples analyzed. The estimated daily intake for 1,3-diphenylguanidine ranged from 0.05 ng/person/day in the mean scenario to 4.0 ng/person/day in the maximum scenario; benzothiazole ranged from 12 to 1,296 ng/person/day; 6PPD ranged from 0.06 to 2.6 ng/person/day; IPPD ranged from 0.04 to 1.1 ng/person/day; CPPD ranged from 0.05 to 2.6 ng/person/day.DiscussionStatistical analyses did not reveal correlation between known growth conditions and tire-derived compound concentrations in the leafy vegetable samples. The estimated daily intake via leafy vegetable consumption was generally lower than or comparable to the estimated daily intake via other known sources. However, we show that tire-derived compounds are taken up by foodstuff, and exposure might be higher for other produce. Future studies are needed to uncover pathways of tire-derived compounds from road to food, assess the exposure to transformation products, and investigate the biological effects associated with this exposure.

Assessment of potential health risks associated with heavy metal concentrations in leafy vegetables in Kerman, Iran

ABSTRACT Despite the growing awareness of the nutritional benefits of leafy vegetables, there is a lack of information about the presence of heavy metals and the associated risks in these products. This study aimed to investigate the concentration of heavy metals in leafy vegetables in Kerman City. The research also assessed the intake of heavy metals and the associated drisks for children and adults who consume these vegetables. The study followed the recommended methods by the US Environmental Protection Agency (USEPA) to evaluate both carcinogenic and non-carcinogenic diseases. A total of 400 leafy vegetable samples, including parsley, coriander, Persian leek, and basil, were randomly collected from agricultural farms in the outskirts of Kerman City. The samples were analysed using a graphite furnace atomic absorption spectrometer to measure the concentrations of lead (Pb), cadmium (Cd), iron (Fe), and copper(Cu). The results revealed that the levels of heavy metals in leafy vegetable samples exceeded the recommended standards set by international organisations such as FAO/WHO, European countries, and Iran. The total target hazard quotient (THQ) for non-carcinogenic diseases resulting from the consumption of leafy vegetables was higher than one for both children and adults in all studied areas, indicating a potential risk of non-carcinogenic diseases associated with the consumption of these vegetables. Furthermore, the average Incremental Lifetime Cancer Risk (ILCR) resulting from exposure to agricultural soil through leafy vegetable consumption exceeded the hazardous and unacceptable range of 104− × 10−6 in both children and adults. This suggests the possibility of carcinogenic diseases caused by Pb and Cd through the consumption of leafy vegetables in all studied areas, with a higher overall risk observed in children compared to adults. In conclusion, while leafy vegetables are widely recognised for their nutritional benefits, our study underscores a critical gap in understanding the presence of heavy metals and the associated risks in these products. The findings reveal that the concentrations of heavy metals in leafy vegetables from Kerman City exceed international standards, posing potential health risks, particularly in children. Further research and regulatory actions are warranted to address this pressing issue and ensure the safety of our food supply.

Microbiological Quality of Irrigation Water and Leafy Vegetables in Dar es Salaam, Tanzania

The quality of water used for the irrigation of leafy vegetables in urban settings is in doubt due to contamination associated with poor hygiene and water pollution. This study examined the microbiological quality of irrigation water and leafy vegetables at Chang’ombe in Dar es Salaam, Tanzania as well as the perceptions and level of awareness of nearby consumers. Water and leafy vegetable samples were analysed for faecal coliform (FC) using standard techniques. Perception and awareness of consumers were collected using a questionnaire survey. The results showed an average FC count of 406.1 ± 16.40 MPN/100 ml for the irrigation water. The sweet potato leaves and amaranth had FC counts of 11.40 ± 5.220 CFU/g and 17.60 ± 11.98 CFU/g respectively. The levels of FC in irrigation water and leafy vegetables were within the allowed limits by WHO and NAS-USA standards respectively but fall short of some stricter European standards for irrigation water. The household survey showed that consumers perceive irrigation water at Chang’ombe as polluted and may be one of the main sources of food contamination. They minimize associated health risks in various ways such as using clean storage, washing and cooking. It was concluded that the microbial quality of water used for irrigation of leafy vegetables at Chang’ombe poses no risk to public health, but based on tighter standards, improved public awareness of hygienic practices is crucial to address potential risks.

Enrichment, Bioaccumulation and Health Risks of Trace Metals in Soils and Leafy Vegetables Grown on the Banks of the Ugandan Lifeline River, River Rwizi

Urban vegetable farming in wetlands and riverbanks are common features of Ugandan cities. However, urbanization has led to various anthropogenic activities that can lead to the pollution of water resources, enrichment of pollutants in soils and, consequently, pollutant bioaccumulation in edible tissues of plants cultivated on such soils. In this study, we report on the levels of six trace metals (TMTs) in 75 samples of leafy vegetables (Brassica oleracea L., Spinacia oleracea L., Amaranthus hybridus L., Cucurbita pepo L. and Solanum nigrum L.) and soils (n = 75) grown on the banks of River Rwizi, the second longest river in Uganda only after the Nile River. The concentrations of TMTs (Mn, Zn, Cd, Pb, Cr and Cu) in edible vegetable tissues and soils were quantified using flame atomic absorption spectrometry. The mean concentrations (in mg kg−1) of the TMTs in the soil samples were 205–373.84 (Mn), 12.72–65.04 (Zn), 0.26–0.42 (Cd), 3.36–16.80 (Pb), 5.96–25.06 (Cr) and 2.83–35.27 (Cu). In vegetable samples, the concentrations ranged from 43.25 to 110.00 (Mn), 1.08 to 1.83 (Cd), 41.06 to 71.20 (Zn), 4.31 to 6.16 (Pb), 0.65 to 0.81 (Cr) and 5.70 to 14.35 (Cu). With the exception of Mn and Cr, the rest of the TMTs were bioaccumulated in the edible vegetable tissues (bioconcentration factors = 1.03 to 10.71). Considering chronic daily intake through ingestion, dermal contact and inhalation of the TMTs in soils from the banks of River Rwizi, there are no potential non-cancer and carcinogenic health effects that could be experienced in both adults and children. Consumption of leafy vegetables could pose both non-cancer health risks (from ingestion of Zn, Pb, Cr, Mn and Cd) and cancer health risks (due to intake of Cd) in both children and adults. There is therefore a need to enforce regulations to mitigate the pollution of River Rwizi for a more sustainable economic development.

Pesticide Residues in Greenhouse Leafy Vegetables in Cold Seasons and Dietary Exposure Assessment for Consumers in Liaoning Province, Northeast China

Excessive pesticide application in greenhouses leads to elevated levels of pesticide residues, especially in cold seasons, thereby posing a potential dietary exposure risk to the residents’ health. This study aimed to investigate 65 pesticides in 469 leafy vegetable samples collected from greenhouses in Liaoning province between October 2018 and May 2020. Overall, the pesticide levels in 96.4% (452/469) of the samples were below the MRLs established by the Codex Alimentarius Commission. The detection rate of 65 pesticides ranged from 0.2% to 11.9%. Multiple pesticide contamination was common, with dimethomorph being the most recurrent contaminant. The dietary risk assessment study revealed obvious differences in chronic and acute exposure risk values. The chronic risk quotients (RQcs) for leafy vegetable samples were 0.001%–3.993%, indicating an acceptable public health risk for the residents. As two leafy vegetables highly consumed in cold seasons in northeast China, the acute risk quotients (RQas) of Chinese cabbage samples were significantly lower than 100%; however, pakchoi samples exhibited RQa values ranging from 0.159% to 580.529%, showing an unacceptable acute dietary risk. This highlights that, compared to the chronic dietary risks, the potential acute dietary risks induced by the pesticides are higher in greenhouse-grown leafy vegetables during cold seasons.

Assessing Washing Methods for Reduction of Pesticide Residues in Green Leafy Vegetables

The use and import of pesticides have been increasing each year to increase agricultural production. The most highly consumed pesticide in Nepal is fungicide followed by insecticide, herbicide and others. Exposure to these pesticides may result in serious health effects. The main route of exposure is the consumption of contaminated fruits and vegetables. Many studies have shown to reduce the pesticide residues level through various culinary and processing treatments. This experiment was carried out to compare the effectiveness of four washing methods to reduce pesticide residues in vegetables. These comprised of running water method, washing by using NaHCO3, NaCl, and vinegar solution. The leafy vegetable samples, Bok choy (N=61) were purchased from local markets and analyzed for the contents of the two pesticides, 2,4-D and atrazine. Samples were extracted using Quick, Easy, Cheap, Effective, Rugged, and Safe (QuEChERS) method and analyzed by liquid chromatography coupled with tandem mass spectrometry (LC-MS/MS) with stable isotopically-labelled internal standards. The quality of the method was examined in terms of accuracy, precision, linearity, limit of detection (LOD) and limit of quantification (LOQ). Washing vegetables under running tap water significantly decreased (p<0.05) 2,4-D residues by 50%. However, atrazine residues were not reduced significantly from washing under running water but washing with vinegar had a significant effect. This study suggests that washing vegetables before consumption is important to reduce intake of pesticides and associated health risks.
 
 

HRMS analysis of pesticides in vegetables from Shanghai and risk assessment

ABSTRACT A rapid analytical method for the simultaneous determination of 550 pesticide residues in vegetable samples was developed based on ultra-high performance liquid chromatography-tandem Q/Orbitrap high-resolution mass spectrometry (UPLC-Q/Orbitrap-HRMS). To investigate the risk of exposure to pesticide residues through vegetable consumption, 704 leafy vegetable samples from Shanghai were analysed for multiple residues using this method. A total of 54 pesticide residues were identified in these vegetable samples and 302 samples contained one or more pesticide residue. The levels of the detected pesticides did not pose a health risk in the long term and were acceptable according to the results of the chronic dietary risk assessment. Risk rankings displayed that most of the pesticides were low to medium risk. The findings of this study provide a reference for future pesticide monitoring programmes.

Effects of different drying methods on the micronutrients of four leafy vegetables traditionally consumed by some Clans in Izzi and Unwana, Ebonyi State, Nigeria

This study was carried out to evaluate the effects of different drying methods (Freeze drying, shade drying and oven drying at varied temperatures of 40oC, 50oC and 60oC) on the micronutrients (mineral and vitamin) contents of L. cupanioides, F. ottonifolia, P. osun and C. pentandra. The minerals contained in both dried and fresh leafy vegetable samples were analyzed by the dry ash extraction method, while vitamins (A, B1, B2, B6 and E) contents of the leafy vegetable samples were determined spectrophotometrically. Vitamin C was determined titrimetrically after homogenizing each sample in 50ml 5.6M EDTA solution. The results from the study revealed that the various drying methods affected the leafy vegetable samples within and between them in the same pattern but to different degrees resulting to moisture lose with increase in minerals and increase in vitamin concentrations when compared with the fresh leafy vegetable samples. Freeze drying and shade drying had the best micronutrients retention effects across all the leafy vegetable samples while oven drying at varied temperatures of 40oC, 50oC and 60oC had gradual decrease in minerals and vitamins retention effects as the temperature increases. The difference in mineral and vitamin concentrations retention with respect to drying methods decreased in this order: Freeze drying > shade drying > oven drying at 40oC > oven drying at 50oC > oven drying at 60oC. The results of the various micronutrients for both fresh and dried leafy vegetable samples in this study ranged as thus: Calcium (72.59–398.10mg/100g), magnesium (41.16–461.07mg/100g), phosphorus (79.28–306.11mg/100g), iron (2.11–32.11mg/100g), zinc (0.19–18.88mg/100g), sodium (29.10–326.51mg/100g), potassium (0.8-196.31mg/100g), vitamin B1 (0.31– 4.22mg/100g), vitamin B2 (0.31 –1.49mg/100g),vitaminB6 (0.36–3.91mg/100g), vitamin A (110.01–548.22ug/g), vitamin C (159.84–818.46mg/100g) and vitamin E (0.16– 9.91mg/100g). In conclusion, the freeze drying and shade drying are the best drying methods for producing dried traditional leafy vegetables with higher micronutrients retention than oven drying at varied temperatures (40oC, 50oC and 60oC).

Quantifying Bioaccumulation Factors of Food Cultivars in the Vicinity of Coal Mining: A Study in Ngwo, Akwuke, and Udi Communities, Enugu State, Nigeria

Heavy metal contamination resulting from coal mining activities poses a substantial threat to both environmental stability and human health. This study delves into the bioaccumulation factors of various food cultivars within the coal mining regions of Ngwo, Akwuke, and Udi Communities in Enugu State, Nigeria. Heavy metals, including lead, cadmium, nickel, manganese, and chromium, have been recognized as significant contaminants responsible for various detrimental health effects. The presence of these metals in the environment, particularly in soil, water, and subsequently in food crops, leads to indirect human exposure through the food chain, thereby triggering several health risks. This research focuses on assessing the levels of heavy metal bioaccumulation in food cultivars and their potential implications for human health. Samples of leafy vegetables and tubers were collected from different locations within the communities and processed following recommended methods. The digestion process involved the use of concentrated acids and subsequent analysis through Atomic Absorption Spectrophotometry (AAS) to quantify the concentration of heavy metals. Bioaccumulation factors (BAF) were determined by establishing the ratio of metal concentrations in the plants to those in water. Results indicated significant variations in bioaccumulation factors among different cultivars and study sites. For instance, the bioaccumulation of manganese and chromium in pumpkin from Akwuke was notably higher compared to Udi and Ngwo, while lead and cadmium levels were significantly higher in Udi. Similar trends were observed in scent leaf and cassava samples, suggesting differential metal accumulation based on cultivar type and geographical location. The findings underscore the concerning levels of heavy metal bioaccumulation, especially high cadmium accumulation in certain food cultivars, posing potential health hazards to communities reliant on these crops. This study emphasizes the critical need for effective environmental management strategies and water treatment practices in these regions to mitigate health risks associated with heavy metal exposure through food consumption. Keywords: Heavy metals, Bioaccumulation factors, Food cultivars, Coal mining, Environmental health, Nigeria.

Contamination Levels and Phenotypic and Genomic Characterization of Antimicrobial Resistance in Escherichia coli Isolated from Fresh Salad Vegetables in the United Arab Emirates.

Contaminated fresh produce has been identified as a vehicle for human foodborne illness. The present study investigated the counts, antimicrobial resistance profile, and genome-based characterization of Escherichia coli in 11 different types of fresh salad vegetable products (n = 400) sampled from retailers in Abu Dhabi and Dubai in the United Arab Emirates. E. coli was detected in 30% of the tested fresh salad vegetable items, with 26.5% of the samples having an unsatisfactory level (≥100 CFU/g) of E. coli, notably arugula and spinach. The study also assessed the effect of the variability in sample conditions on E. coli counts and found, based on negative binominal regression analysis, that samples from local produce had a significantly higher (p-value < 0.001) E. coli count than imported samples. The analysis also indicated that fresh salad vegetables from the soil-less farming system (e.g., hydroponic and aeroponic) had significantly (p-value < 0.001) fewer E. coli than those from traditional produce farming. The study also examined the antimicrobial resistance in E. coli (n = 145) recovered from fresh salad vegetables and found that isolates exhibited the highest phenotypic resistance toward ampicillin (20.68%), tetracycline (20%), and trimethoprim-sulfamethoxazole (10.35%). A total of 20 (13.79%) of the 145 E. coli isolates exhibited a multidrug-resistant phenotype, all from locally sourced leafy salad vegetables. The study further characterized 18 of the 20 multidrug-resistant E. coli isolates using whole-genome sequencing and found that the isolates had varying numbers of virulence-related genes, ranging from 8 to 25 per isolate. The frequently observed genes likely involved in extra-intestinal infection were CsgA, FimH, iss, and afaA. The β-lactamases gene blaCTX-M-15 was prevalent in 50% (9/18) of the E. coli isolates identified from leafy salad vegetable samples. The study highlights the potential risk of foodborne illness and the likely spread of antimicrobial resistance and resistance genes associated with consuming leafy salad vegetables and emphasizes the importance of proper food safety practices, including proper storage and handling of fresh produce.

Prevalence of Clostridium perfringens and Clostridium difficile carrying cpa, tcdA toxin genes in raw meat and leafy vegetables

The genus Clostridium is a Gram-positive, spore-forming bacterium. Most species of&amp;nbsp;Clostridium spp. usually are found in soil, water, dead plants, animal carcasses, and play&amp;nbsp;an important role in the decomposition of substances in nature. Raw meat and fresh&amp;nbsp;vegetable are more likely to be contaminated with spores or vegetative cells of the genus&amp;nbsp;Clostridium. The study results showed that the percentage of samples contaminated with&amp;nbsp;raw meat and leafy vegetables collected at markets in Dong Da, Ha Dong and Hoang Mai&amp;nbsp;districts infected with C. perfringens was 26.67% (n = 150) and 26.82% (n = 220). The&amp;nbsp;percentage of raw meat and leafy vegetable samples contaminated with C. difficile was&amp;nbsp;very low with 6.00% (n = 150) and 0.9% (n = 220), respectively. Gene amplification&amp;nbsp;reactions revealed the presence of cpa toxin gene in all C. perfringens strains and detected&amp;nbsp;02 C. difficile strains carrying the tcdA gene.

Transfer Factor of Radionuclides from Soil to Leafy Vegetables in Iraq Using Gamma Ray Spectroscopy

The activity concentration of natural radioactivity levels, of artificial cesium and transfer factor from soil to plants in agricultural areas at Al- Yusiefya region were determined by using NaI (Tl) detector spectrometer. Ten species of leafy plants have been selected: Spinach, Parsley, Watercress, Lettuce, Rashad, Radish, Green onion, Turnip green, Green beet and Mint. The mean activity concentrations of 238U, 232Th, 40K and 137Cs in leafy vegetable samples were 12.4±3.8, 14.8±4.7, 283±93 and 1.06±0.99 Bg/kg, and in soil samples were 15.9±4.3, 16.1±5.2, 298.5±3.9, and 1.11±0.37 Bq/kg. The radiation hazard indices were evaluated (radium equivalent, external hazard index, annual effective dose, absorbed dose rate) were within the permissible values except for excess lifetime cancer risk. The mean transfer factor values of 226 Ra, 232Th, 40K, and 137Cs were 0.89±0.2, 0.9±0.2 , 1.02±0.3, and 0.77±0.25. The leafy vegetable are safe for consumption and the studied area does not pose a considerable radiological threat .

Quantification of 363 Pesticides in Leafy Vegetables (Dill, Rocket and Parsley) in the Turkey Market by Using QuEChERS with LC-MS/MS and GC-MS/MS

Contamination of agricultural products with pesticide residues is a growing concern due to their adverse health effects and increasing worldwide usage of pesticides. In 2021 a total of 200 samples of green leafy vegetables, including 80 dill, 80 rocket and 40 parsley, purchased from greengrocer shops, markets and bazaars in Corum Province, Turkey, were monitored for pesticide residues. In green leafy vegetables, 363 pesticides were analyzed using a quick, easy, cheap, effective, rugged, and safe (QuEChERS) sample preparation, followed by liquid chromatography coupled to mass spectrometry (LC-MS/MS) for 311 residues and gas chromatography coupled to mass spectrometry (GC-MS/MS) for 52 residues. The method was in-house validated at two fortification levels, and satisfactory recoveries and precisions were achieved for all residues. No quantifiable residues were found in 35% of the samples, whereas 43 residues belonging to 24 different chemical classes were detected in 130 green leafy vegetables. Among the green leafy vegetables, the highest occurrence frequency was recorded in the rocket, followed by dill and parsley. In 46% of the green leafy vegetables, the residue levels exceeded European Union Maximum Residue Levels (EU MRLs). The most frequently detected pesticides were pendimethalin (22.5%), diuron (38.7%) and pymetrozine (52.5%) in dill, rocket and parsley, respectively.

Microbial Communities on Samples of Commercially Available Fresh-Consumed Leafy Vegetables and Small Berries

Microbial communities on fresh-consumed plant products are an important predictor of quality and safety for the consumer. Totally, 45 samples of berry fruits (8 blackberries, 9 blueberries, 8 strawberries, 8 raspberries, 12 currants) and 40 samples of leafy vegetables (20 lettuce, 6 cornsalad, 8 rocket, 8 spinach) were analyzed using cultivation and DNA-depended methods. Total aerobic count, coliforms, and yeasts were significantly lower in fruits while counts of filamentous fungi were similar. Pantoea, Enterobacter, and Klebsiella were the most common colonies grown on VRBL agar. Salmonella was detected in single sample of cornsalad using qPCR but no sample contained Escherichia coli harboring stx1, stx2 and intimin genes. Sequencing of V4 region of bacteria 16S rRNA and ITS2 region of fungi amplified from plant tissue-extracted DNA confirmed different composition of fruit and vegetable microbiome. Pre-enrichment of bacteria in phosphate buffered water allowed deeper analysis of Enterobacteriaceae using V4–V5 region of 16S rRNA while differences among communities were described similarly. Pantoea, Klebsiella, or Staphylococcus were more frequent in berries while Pseudomonas, Flavobacterium, or Sphingobacterium in leafy vegetables. Comparison of inner and outer leaves of head-forming lettuces (6 iceberg, 5 romain) showed that outer leaves are colonized by more bacteria with higher diversity. Microbiological safety of fresh production requires more attention as the potentially pathogenic bacteria were detected, particularly in leafy vegetables. However, the true pathogenicity of such bacteria needs further research.

Optimization of ultrasonication-assisted extraction conditions using RSM-I-Optimal experimental design to recover vitamin D2 and K1 from selected green leafy vegetable samples

This study employed the response surface methodology to optimize the extraction conditions for recovering vitamins D2 and K1 from green leafy vegetables using ultrasonication-assisted extraction. The vitamin content was determined using an Accucore C18 column and a UPLC-Q-ToF/MS method. An RSM-I-Optimal design was used for designing the experiment to find the best combination of solvent level (mL), sonication time (min), sonication frequency (kHz), and temperature (°C). The experimental data from a 25-sample set were fitted to a second-order polynomial equation using multiple regression analysis. The extraction models had R2 values of 0.895 and 0.896, respectively, and the probability values (p < 0.0001) indicated that the regression model was highly significant. The optimal extraction conditions were: solvent level of 65 mL, sonication time of 45 min, sonication frequency of 70 kHz, and temperature of 45 °C. Under these conditions, the predicted recovery (%) values for vitamins D2 and K1 were 90.7% and 90.4%, respectively. This study has the potential to use the reported extraction method for routine quantification of vitamins D2 and K1 in the laboratory using UPLC-Q-ToF/MS.

Improved Analytical Approach for Determination of Tropane Alkaloids in Leafy Vegetables Based on µ-QuEChERS Combined with HPLC-MS/MS.

This work presents an optimized methodology based on the miniaturization of the original QuEChERS (μ-QuEChERS) followed by liquid chromatography coupled to mass spectrometry (HPLC-MS/MS) for the determination of tropane alkaloids (TAs), atropine, and scopolamine in leafy vegetable samples. The analytical methodology was successfully validated, demonstrating quantitation limits (MQL) ≤ 2.3 ng/g, good accuracy, and precision, with recoveries between 90–100% and RSD ≤ 13% for both analytes. The method was applied to the analysis of TA-producing plants (Brugmansia versicolor, Solandra maxima, and Convolvulus arvensis). High concentrations of scopolamine were found in flowers (1771 mg/kg) and leaves (297 mg/kg) of B. versicolor. The highest concentration of atropine was found in flowers of S. maxima (10.4 mg/kg). Commercial mixed leafy vegetables contaminated with B. versicolor and S. maxima were analysed to verify the efficacy of the method, showing recoveries between 82 and 110% for both analytes. Finally, the method was applied to the analysis of eighteen samples of leafy vegetables, finding atropine in three samples of mixed leafy vegetables, with concentrations of 2.7, 3.2, and 3.4 ng/g, and in nine samples with concentrations ≤MQL. In turn, scopolamine was only found in a sample of chopped Swiss chard with a concentration ≤MQL.

Prevalence and molecular characterization of shiga toxin-producing Escherichia coli in animal source foods and green leafy vegetables.

Shiga toxin-producing Escherichia coli (STEC) has emerged as important enteric foodborne zoonotic pathogens of considerable public health significance worldwide. The aim of this study was to determine the prevalence of the top seven STEC serotypes and to identify these serotypes in samples of animal source foods and vegetables. A total of 294 samples including 84 meat samples, 135 milk and dairy product samples and 75 green leafy vegetable samples were tested. The samples were harvested in mTSB-broth pre-enriched with novobiocin and then were tested by amplifying 16S shiga toxin (stx1/2), and eae genes using multiplex polymerase chain reaction (m-PCR) assay. A total of 260 (88.4%) samples were positive for E. coli and 29 (11.1%) of them were positive for shiga toxin, and eae genes. The positive samples were cultivated on CHROMAgar STEC and the colonies were evaluated for top seven STEC by m-PCR. The top seven STEC serotypes were detected in 27 (93.1%) of the samples: the STEC O111 serotype in 11 (40.7%) beef samples, STEC O45 in 3 (11.1%) chicken, STEC O145 in 6 (22.2%) parsley, 3 (11.1%) lettuce, 1 (3.7%) spinach, and 1 (3.7%) cheese, and STEC O103 in 2 (7.4%) lettuce samples. None of the samples was found positive for STEC O26, O121, and O157 serotypes. This study highlights the fact that the top seven STEC group poses a great risk in terms of food safety and public health in both animal source foods and vegetables.

Isolation and Genetic Characterization of Gram-negative Bacteria from Different Fresh Retail Vegetables in Nigeria

Aim: The proportion of food borne disease outbreaks as a result of contaminated products has increased over the years. In this study, the genetic characteristics of antibiotic resistant Gram-negative bacteria from different fresh retail vegetables in Okada, Edo state Nigeria was investigated.&#x0D; Place and Duration of Study: In April-May 2021, the study was carried out in the Department of Pharmaceutical Microbiology, Igbinedion University Okada Edo state Nigeria.&#x0D; Methodology: One hundred and eight isolates were isolated from sixteen different retail leafy and salad vegetable samples. Recovered isolates from samples were identified using standard microbiological techniques. Species identification for ten randomly selected isolates was performed by Matrix-assisted laser desorption ionization-time of flight (MALDI-TOF) mass spectrometry and ribosomal multilocus sequence typing (rMLST). Antimicrobial susceptibility testing was performed using the Kirby-Bauer method for 15 antibiotics. Isolates were characterized by whole genome sequencing (WGS).&#x0D; Results: Species identification using MALDI-TOF-MS and ribosomal MLST assigned the 10 randomly selected isolates to four different species. Identified isolates include Proteus mirabilis, Proteus vulgaris, Acinetobacter baumanii and Klebsiella quasipneumoniae. Out of the 10 randomly selected isolates, 60% (6/10) were antibiotic resistant in the antibiotic susceptibility test. WGS data confirmed the identities of the isolates except Proteus vulgaris identified as P. terrae. More than one resistant determinant was detected on the draft genome sequence of 80% (8/10) of the randomly selected isolates especially the regulatory system modulating antibiotic efflux CRP and the plasmid mediated quinolone resistant determinant qnrD1. Significantly, one Proteus mirabilis isolate was sensitive to the antibiotics in the phenotypic testing but had resistance determinants present.&#x0D; Conclusion: This study provides genomic characterization of antibiotic resistant isolates from retail leafy and salad vegetables from Nigeria. Further study is important to understand the public health importance of such resistance and the amount of risk posed to human health by these resistant organisms.

Comparative analysis of phytoconstituents in commonly used vegetables in gas flaring and non-gas flaring communities in southeastern Nigeria

A comparative study to determine the impact of gas flaring (GF) on some phytoconstituents of five commonly used green leafy vegetables was done. Two locations in south-east states in Nigeria, Ibeno in Akwa Ibom State, a gas flaring (GF) community and Nsukka in Enugu State, a non-gas flaring (NGF) community, were used. Five fresh green leafy vegetable samples were used for this study (Amaranthus hybridus, Gnetum africanum, Talinum triangulare, Telfairia occidentalis, and Vernonia amygdalina) and were obtained from community farmlands during the rainy season between August and November, 2016. After collecting and identifying the green leafy vegetables from five different farmlands in GF and NGF areas and at a distance of about 2km radius from the flare site in GF communities, detailed laboratory analysis was done for alkaloids, flavonoids, saponins and tannins. For A. hybridus, the flavonoid and tannin contents in NGF community were significantly (p&lt;0.05) higher than in GF community; G. africanum, the alkaloid and tannin contents were higher in NGF community; T. triangulare, the alkaloid content alone was higher in NGF community; T. occidentalis, the alkaloid, flavonoid, saponin and tannin contents were significantly (p&lt;0.05) higher in the NGF community; V. amygdalina, the tannin content alone was higher in NGF community compared to the GF community. Most green leafy vegetables from NGF community produced higher and better phytoconstituent concentrations than the GF community. This can be attributed to the non-pollution of the former environment.