Survival of Escherichia coli O157:H7 in soil and on carrots and onions grown in fields treated with contaminated manure composts or irrigation water

Many foodborne outbreaks of enterohemorrhagic Escherichia coli O157:H7 infection have been associated with the consumption of contaminated vegetables. On-farm contaminations through contaminated manure or irrigation water application were considered likely sources of the pathogen for several outbreaks. Field studies were done to determine the survival of E. coli O157:H7 on two subterranean crops (carrots and onions), and in soil fertilized with contaminated manure compost or irrigated with contaminated water. Three different types of composts, PM-5 (poultry manure compost), 338 (dairy manure compost) and NVIRO-4 (alkaline stabilized dairy manure compost), and irrigation water were inoculated with an avirulent strain of E. coli O157:H7 at 10⁷ cfu g⁻¹ and 10⁵ cfu ml⁻¹, respectively. A split-plot block design plan was used for each crop, with five treatments (one without compost, three with each of the three composts, and one without compost but with contaminated irrigation water applied) and five replicates for a total of 25 plots, each measuring 1.8×4.6 m², for each crop. Composts were applied to soil as a strip at a rate of 4.5 metric tons ha⁻¹ before carrots and onions were sown. Contaminated irrigation water was sprayed once on the vegetables at the rate of 2 l per plot for this treatment 3 weeks after carrots and onions were sown. E. coli O157:H7 survived in soil samples for 154–196 days, and was detected for 74 and 168 days on onions and carrots, respectively. E. coli O157:H7 survival was greatest in soil amended with poultry compost and least in soil containing alkaline-stabilized dairy manure compost. Survival profiles of E. coli O157:H7 on vegetables and soil samples, contaminated either by application of contaminated compost or irrigation water, were similar. Hence, preharvest contamination of carrots and onions with E. coli O157:H7 for several months can occur through both contaminated manure compost and irrigation water.     

Polyphenols,carotenoids, and ascorbic acid in underutilized medicinal vegetables

The polyphenols, carotenoids, ascorbic acid, and protein were determined in 24 underutilized medicinal vegetables from Indonesia. Anacardium occidentale, Sauropus androgynus (L.) Merr., and Moringa pterygosperma Gaertn. leaves were rich sources of flavonoids, with 118–144 mg/100 g fresh weight. Quercetin, kaempferol, and chlorogenic acid were the predominant polyphenols among those measured in vegetables. Polyscias pinnata leaves and Solanum torvum Swartz fruits had the most phenolic acids, with 53 and 36 mg/100 g, respectively. Moringa pterygosperma had the most carotenoids among vegetables, with 14 mg β-carotene equivalents (βCE)/100 g. Ascorbic acid content of fresh vegetables was 12.03–494.43 mg/100 g. A. occidentale, S. androgynus, Ocimum americanum L., Cosmos caudatus H.B.K., and Carica papaya L. (papaya) leaves had more than 100 mg ascorbic acid/100 g. Thus, a number of underutilized vegetables from Indonesia may be rich sources of functional components including polyphenols and ascorbic acid.     

The influence of preparation method on children’s liking for vegetables

This study aimed to investigate how different preparation methods influence children’s liking for vegetables. Participants were children from three age groups (4–6 years N = 46; 7–8 years N = 25; 11–12 years N = 23) and young adults (18–25 years N = 22). The participants tasted and ranked six preparation methods for carrots and French beans: mashed, steamed, boiled, stir-fried, grilled and deep-fried. In addition, the different vegetable preparations were rated on 15 attributes. All participants preferred boiled and steamed vegetables over the other preparations (p < 0.05). Boiled and stir-fried were the most familiar preparation methods for both vegetables. Vegetable liking was positively related to a uniform surface and the typical vegetable taste, and moderately related to crunchiness, whereas brown colouring and a granular texture were negatively related to vegetable liking. On the basis of these results, we conclude that children’s vegetable liking is influenced by a complex mixture of a uniform appearance, easily controllable textures and a typical, familiar vegetable taste.     

Effect of blanching on the antioxidant properties of some tropical green leafy vegetables

Eight popularly consumed green leafy vegetables in Nigeria namely: Structium sparejanophora, Amarantus cruentus, Telfairia occidentalis, Baselia alba, Solanum macrocarpon, Corchorus olitorus, Vernonia amygdalina, and Ocimum gratissimum were blanched in hot water for 5 mins. The antioxidant properties of the fresh and blanched green leafy vegetables were subsequently determined. The total phenol, ascorbic acid and the antioxidant potentials as typified by reducing property and free radical scavenging activity was also determined. The results of the study revealed that blanching cause a significant (P<0.05) increase in the total phenol [fresh (0.1–0.3 g/100 g), blanched (0.2–0.6 g/100 g)] content of the green leafy vegetables except in Amarantus cruentus and Vernonia amygdalina where there was no change. Conversely, there was a significant (P<0.05) decrease in the vitamin C [fresh (43.5–148.0 mg/100 g), blanched (15.8–27.3 mg/100 g)], reducing property [fresh (0.5–1.5 absorbance), blanched (0.1–0.6 absorbance)] and free radical scavenging ability [fresh (20.0–51.4%), blanched (16.4–47.1%)] of the blanched green leafy vegetables except in Structium sparejanophora, where there was no change in the reducing property (0.6 absorbance) and free radical scavenging ability (59.8%) of the blanched vegetable. In view of this it could be concluded that blanching of vegetables though makes green leafy vegetables more palatable and less toxic, however it reduces their antioxidant properties drastically.     

The impact of extreme weather events on Salmonella internalization in lettuce and green onion

Salmonella internalization is an important issue in raw vegetable consumption because washing usually cannot remove or inactivate the internalized pathogens effectively. In this study, the impact of extreme weather events, drought and heavy rains, caused by climate change on the internalization of Salmonella Typhimurium was investigated. Two leafy green fresh produce, iceberg lettuce and green onion were chosen. Rhizosphere soil inoculation was conducted to mimic the contamination routes via soil and then root uptake. Most internalized S. Typhimurium were found in lettuce leaves and in the root portions of green onion under all three irrigation conditions (optimal, drought, storm). In general, high concentration of soil inoculation facilitated the internalization level in both lettuce and green onion. Under extreme weather conditions, the internalization of S. Typhimurium in lettuce occurred when the soil was contaminated with a high level of bacteria (8–9 log colony forming unit (CFU)/g soil) and under these conditions, the internalization level was higher than the lettuce grown at the optimal water condition, except with 8 log CFU/g contamination (storm). Under drought, the results showed high variation, but the level of internalization of S. Typhimurium in lettuce increased by 16 times (1.21 log CFU/g) and 27 times (1.43 log CFU/g) compared to the optimally irrigated group when the soil was contaminated with 8 log and 9 log CFU/g soil, respectively. Ten-fold increased internalization was observed in the over-irrigated lettuce leaves when the soil was contaminated with 9 log CFU/g soil. The green onion samples showed ~ 4 log CFU/g green onion of S. Typhimurium internalization when exposed to high level of contamination (> 7 log CFU/g soil), which is a much higher internalization rate than the lettuce (average 2–3 log CFU/g). However, from the green onion experiments, no apparent patterns of water stress that affect on the levels on the Salmonella internalization were observed.     

Children’s liking and intake of vegetables: A school-based intervention study

This study investigated effects on vegetable liking and intake gained from exposing children to snack vegetables of different liking levels. In total, 345 9–11-year-old children participated. The intervention consisted of two exposure periods. First, children were either exposed to a neutrally liked vegetable (cauliflower), a mixture of a neutrally liked and a liked (sugar snap peas) vegetable, or a mixture of a neutrally liked and a disliked (celery) vegetable. In the second, period all children were served all vegetables. Intake of individual vegetables was measured daily. Liking was assessed before and after exposures and at a subsequent follow-up. Liking for most vegetables decreased during the exposure periods but tended to recover somewhat during follow-up. Intake of all vegetables was either stable or decreased during the intervention, no increases were observed. Intake levels depended on type of vegetable servings: When served with a liked vegetable, children consumed more of a neutrally liked vegetable than when served alone (p = 0.0005) or together with a disliked vegetable (p = 0.005).     

Genetic and environmental influences on liking and reported intakes of vegetables in Irish children

Variation in the bitterness of 6-n-propylthiouracil (PROP) is partially explained by polymorphisms in the TAS2R38 gene. Based on their perception of bitterness from PROP, people may be classified into non-, medium and supertasters. PROP perception has previously been linked to liking for cruciferous vegetables in children in some studies, but only one study to date has examined TAS2R38 genotype and its relationship with vegetable intake in children. Children’s vegetable consumption generally does not meet the recommended guidelines, thus the present study aimed to examine the influence of oral sensory measures, genetic variation and social factors on vegetable liking and intake. Vegetable liking in 7–13 year old Irish children (n = 525) was measured on a 5-point liking scale, and dietary intakes were assessed via a 3-day diet history. Vegetable intakes were calculated and standardised per kg body weight. A subset of children (n = 485) were genotyped for SNPs in TAS2R38, (A49P, V262A, I296V), and fungiform papilla (FP) were counted. The bitterness of PROP and sweetness of sucrose were rated on a generalised labelled magnitude scale (gLMS). PROP and sucrose intensity were significantly correlated (R² = 0.33, p = 0.001), although neither sucrose intensity nor FP density differed across the TAS2R38 genotype groups. Supertasters were less likely than nontasters to have tried/tasted cruciferous vegetables p < 0.04). A small, positive correlation was seen in FP density and vegetable intake, but only in the AVI homozygous children, (R² = 0.17, p = 0.035). 174 Nutrient acceptable children reported an intake of one or more of the vegetables of interest in the 3-day period. Liking of cruciferous vegetables and reported intake were significantly correlated. In multiple regression analyses in this subsection of the cohort, socioeconomic status (SES) and gender were more important than PROP bitterness or TAS2R38 genotype in predicting intakes (approximately 15% of liking and 67% of intake was explained by these models). Overall, neither PROP taster status nor TAS2R38 genotype alone had significant impact on bitter vegetable liking or intake. Further research into FP density and vegetable liking and intake may be warranted.     

Vegetable preparation practices for 5–6 years old Australian children as reported by their parents; relationships with liking and consumption

Vegetables are the food category least accepted by children, which is a key reason for their low intake. Common sense suggests that vegetable preparation, liking and consumption is idiosyncratic to each vegetable, e.g. carrots may be eaten raw, but raw broccoli may be unacceptable, however scientific evidence is largely lacking. This study measured children’s experiences, liking and consumption of vegetables in relation to preparation practices at home. Questionnaire data were collected for a comprehensive range of preparation methods (raw, boiling, steaming, frying, roasting, and seven ways of preparing it with other dishes (e.g. soup)) across five common vegetables, i.e. carrot, potato, broccoli, cauliflower, and green beans. Measures included experience with preparation methods (yes/no), liking (9 point hedonic scale) and consumption frequency (5 point scale). Data were reported by parents for their child (N = 82, 5–6 years, low and high vegetable intake), and child/parent pairs were recruited from the Sydney metropolitan area. Parents reported that children consumed an average of 6.8 (SD 3.4) different preparation methods for vegetables at home, including many mixed dishes. The number and type of preparations the child consumed depended on the vegetable type (p < .0001). Preparation method was associated with liking of carrot and potato (both p < .0001), and with consumption frequency of all vegetables (all p < .05). The most and least liked preparations were vegetable specific. Parents reported that vegetables in mixed dishes were generally well accepted by their children, and flavourings were added on average by 54%. The results also showed that a higher vegetable consumption was related to a higher liking, and exposure to more preparation methods. This study demonstrates the potential for further experimental research into preparation practices to increase vegetable acceptance and intake in children. A vegetable by vegetable approach is recommended, with potential cross-vegetable opportunities for flavour–flavour learning and flavour masking strategies including the use of mixed dishes.     

Exploring the effects of genotypical and phenotypical variations in bitter taste sensitivity on perception,liking and intake of brassica vegetables in the UK

Brassicaceous vegetables (BV) have chemoprotective effects and yet consumption of BV in the UK is low. Previous studies suggest perception, liking and intake of BV are influenced by bitter taste sensitivity which this study further explores. Phenotypical taste sensitivity of 136 subjects was classified using propythiouracil (PROP) and sodium chloride and fungiform papillae density (FPD) was measured from tongue images. Polymorphisms of TAS2R38 and gustin (CA6) genes were analysed. Liking and bitterness of four raw vegetables (two BV (broccoli and white cabbage) and two non-BV (spinach and courgette)), as well as habitual consumption, were evaluated.There was a significant association between TAS2R38 genotype and PROP taster status (p < 0.0001) and between FPD and PROP taster status (p = 0.029). Individuals with greater sensitivity for PROP predominantly had TAS2R38 PAV/PAV genotype and greater FPD. BV were perceived as more bitter than non-BV (p < 0.0001) with PAV/PAV subjects perceiving significantly stronger bitter intensity. There was a significant difference in liking for the four vegetables (p = 0.002), and between consumers of different TAS2R38 genotype (p = 0.0024). Individuals with TAS2R38 AVI/AVI genotype liked BV more. Regarding intake, both PAV/PAV and AVI/AVI individuals consumed more total vegetables and BV than PAV/AVI. Although PROP nontasters tended to consume more vegetables and BV than the other two phenotype groups, liking and vegetable intake were not significantly affected by taste phenotype. Although there was not a significant effect of CA6 genotype on bitterness ratings, there was a significant interaction between CA6 and TAS2R38, and in addition CA6 genotype was significantly associated with BV intake. However, these effects require validation as the proportions of the population with the CA6 G/G genotype was extremely small (7%).Our results confirmed that bitter taste perception in vegetables was influenced by both genotype and phenotype of bitter taste sensitivity. Moreover, our findings demonstrated that neither genotype nor phenotype of taste sensitivity alone accurately predict vegetable liking and intake as demographic factors were found to have a substantial influence.     

Taste intensities of ten vegetables commonly consumed in the Netherlands

Bitterness has been suggested to be the main reason for the limited palatability of several vegetables. Vegetable acceptance has been associated with preparation method. However, the taste intensity of a variety of vegetables prepared by different methods has not been studied yet. The objective of this study is to assess the intensity of the five basic tastes and fattiness of ten vegetables commonly consumed in the Netherlands prepared by different methods using the modified Spectrum method. Intensities of sweetness, sourness, bitterness, umami, saltiness and fattiness were assessed for ten vegetables (cauliflower, broccoli, leek, carrot, onion, red bell pepper, French beans, tomato, cucumber and iceberg lettuce) by a panel (n = 9) trained in a modified Spectrum method. Each vegetable was assessed prepared by different methods (raw, cooked, mashed and as a cold pressed juice). Spectrum based reference solutions were available with fixed reference points at 13.3 mm (R1), 33.3 mm (R2) and 66.7 mm (R3) for each taste modality on a 100 mm line scale. For saltiness, R1 and R3 differed (16.7 mm and 56.7 mm). Mean intensities of all taste modalities and fattiness for all vegetables were mostly below R1 (13.3 mm). Significant differences (p < 0.05) within vegetables between preparation methods were found. Sweetness was the most intensive taste, followed by sourness, bitterness, fattiness, umami and saltiness. In conclusion, all ten vegetables prepared by different methods showed low mean intensities of all taste modalities and fattiness. Preparation method affected taste and fattiness intensity and the effect differed by vegetable type.     

Vanillin inhibits pathogenic and spoilage microorganisms in vitro and aerobic microbial growth in fresh-cut apples

The antimicrobial effect of vanillin against four pathogenic or indicator organisms; Escherichia coli, Pseudomonas aeruginosa, Enterobacter aerogenes, and Salmonella enterica subsp. enterica serovar Newport and four spoilage organisms; Candida albicans, Lactobacillus casei, Penicillum expansum, and Saccharomyces cerevisiae that could be associated with contaminated fresh-cut produce, was examined. The minimal inhibitory concentration (MIC) of vanillin was dependent upon the microorganism and this ranged between 6 and 18 mM. When incorporated with a commercial anti-browning dipping solution (calcium ascorbate, NatureSeal™), 12 mM vanillin inhibited the total aerobic microbial growth by 37% and 66% in fresh-cut ‘Empire’ and ‘Crispin’ apples, respectively, during storage at 4 °C for 19 days. Vanillin (12 mM) did not influence the control of enzymatic browning and softening by NatureSeal. These results provide a new insight for vanillin as a potential antimicrobial agent for refrigerated fresh-cut fruits and vegetables.     

The consumer acceptance of novel vegetable-enriched bread products as a potential vehicle to increase vegetable consumption

Currently UK fruit and vegetable intakes are below recommendations. Bread is a staple food consumed by approximately 95% of adults in western countries. In addition, bread provides an ideal matrix by which functionality can be delivered to the consumer in an accepted and convenient food. Therefore, enriching bread with vegetables may be an effective strategy to increase vegetable consumption. This study evaluated bread enriched with red beetroot, carrot with coriander, red pepper with tomato or white beetroot (40 g vegetable per 100 g) compared to white control bread (0 g vegetable) for consumer acceptance. Consumers (n = 120) rated their liking of the breads overall, as well as their liking of appearance, flavour and texture using nine-point hedonic scales. Product replacement and purchase intent of the breads were rated using five-point scales. The effect of providing consumers with health information about the breads was also evaluated. There were significant differences in overall liking (P < 0.0001), as well as liking of appearance (P < 0.0001), flavour (P = 0.0002) and texture (P = 0.04), between the breads. However, the significant differences resulted from the red beetroot bread which was significantly (P < 0.05) less liked compared to control bread. There were no significant differences in overall liking between any of the other vegetable-enriched breads compared with the control bread (no vegetable inclusion). The provision of health information about the breads did not increase consumer liking of the vegetable-enriched breads. In conclusion, this study demonstrated that vegetable-enriched bread appeared to be an acceptable strategy to increase vegetable intake, however, liking depended on vegetable type.     

Ameliorating effects of ethyl acetate fraction from onion (Allium cepa L.) flesh and peel in mice following trimethyltin-induced learning and memory impairment

The anti-amnesic effects of onion (Allium cepa L.) flesh (OF)¹ and peel (OP)² on trimethyltin (TMT)³-induced learning and memory dysfunction were investigated to confirm learning and memory function. The inhibitory effect against cellular acetylcholinesterase (AChE)⁴ showed that the EtOAc fraction of OP (EOP⁵, IC₅₀ value = 37.11 μg/mL) was higher than the EtOAc fraction of OF (EOF⁶, IC₅₀ value = 433.34 μg/mL). The cognitive effects in ICR mice were also evaluated using Y-maze, passive avoidance, and Morris water maze tests. After the behavioral tests, AChE activity (control = 100%, TMT = 128%, EOF 20 = 108%, EOP 10 = 104%, and EOP 20 = 98%), superoxide dismutase (SOD)⁷ activity, oxidized glutathione (GSSG)⁸/total glutathione (GSH)⁹ and malondialdehyde (MDA)¹⁰ production were examined. These results indicate that both EOF and EOP improved learning and memory function. The main compounds of the EOF and EOP were analyzed by Q-TOF UPLC/MS, and the results were as follows: The EOF (quercetin and quercetin-4′-glucoside) and the EOP (quercetin-4′-glucoside and isorhamnetin-4′-glucoside). Consequently, our results suggest that both EOF and EOP could be efficacious in improving cognitive function through AChE inhibition and antioxidant activity in mice brains.     

Evaluating eggplant (Solanum melongena L) genotypes for bioactive properties: A chemometric approach

Thirty four genotypes of eggplant and its wild relatives were evaluated for their total phenolics, flavonoid content and antioxidant capacity. Free radical scavenging was evaluated using four in-vitro assays, viz. FRAP (Ferric reducing antioxidant power), CUPRAC (cupric reducing antioxidant capacity), TEAC (Trolox equivalent antioxidant capacity) and DPPH (2, 2-diphenylpicrylhydrazyl). Total phenolics in eggplant showed a wide variation, ranging from 22.62 to 234.46 mg gallic acid equivalents (GAE)/100 g fw (244.28 to 2990.64 mg GAE/100 g dw). With the exception of Solanum aethiopicum and its accessions (Ac-1, Ac-2 and Ac-3), all wild relatives had significantly (p < 0.05) higher total phenolics and flavonoid content than cultivated ones. Total antioxidant capacity (FRAP) in wild genotypes ranged from 1.13 to 8.04 μmol Trolox (TE)/g. The hierarchy in decreasing order was Solanum khasianum > Solanum torvum > Solanum sisymbriifolium > Solanum incanum > Solanum integrifolium > S. aethiopicum. The antioxidant capacity correlated high with total phenolics in all assays. In cultivated group, JBR-99 and RCMBL-3 possessed high antioxidant capacity than the rest. Principal component analysis (PCA) and Hierarchical cluster analysis (HCA) revealed distinct similarity between JBR-99 (green), S. sisymbriifolium, S. khasianum and S. torvum. Overall results indicate that the wild species of S. torvum, S. incanum and S. sisymbriifolium are potential candidates for improving the functional quality of cultivated eggplant.     

Antioxidant activity and phenolic content of roots,tubers and vegetables commonly consumed in India

Epidemiological evidence suggests that consumption of vegetables can prevent degenerative diseases caused by oxidative stress. Considering scanty data available on antioxidant activity (AOA) of roots, tubers and vegetables commonly consumed in India, the objective of the present study was to assess their AOA and relate it to their total phenolic content. AOA was assessed in vegetables (n = 19) and roots/tubers (n = 10) by DPPH (2,2′-diphenyl-1-picryl hydrazyl) scavenging activity and FRAP (ferric reducing antioxidant power) methods and the total phenolic content (TPC) using Folin–Ciocalteu reagent. Although AOA as well as TPC showed wide variation among roots, tubers and vegetables studied. AOA (both DPPH and FRAP) was significantly correlated with TPC among all the foods studied, with the correlation coefficient (r) values being 0.76 and 0.85 (p < 0.01) respectively with FRAP and DPPH activity among roots and tubers while among the vegetables studied, the corresponding values were 0.85 and 0.79 (p < 0.01) respectively. The results suggest that phenolic compounds may be significant contributors to the AOA of the vegetables, roots and tubers studied.     

Heavy metal accumulation in vegetables irrigated with water from different sources

The present study was carried out to assess levels of different heavy metals like iron, manganese, copper and zinc, in vegetables irrigated with water from different sources. The results indicated a substantial build-up of heavy metals in vegetables irrigated with wastewater. The range of various metals in wastewater-irrigated plants was 116–378, 12–69, 5.2–16.8 and 22–46 mg/kg for iron (Fe), manganese (Mn), copper (Cu) and zinc (Zn), respectively. The highest mean levels of Fe and Mn were detected in mint and spinach, whereas the levels of Cu and Zn were highest in carrot. The present study highlights that both adults and children consuming vegetables grown in wastewater-irrigated soils ingest significant amount of these metals. However, the values of these metals were below the recommended maximum tolerable levels proposed by the [Joint FAO/WHO Expert Committee on Food Additives (1999). Summary and conclusions. In 53rd Meeting, Rome, June 1–10, 1999]. However, the regular monitoring of levels of these metals from effluents and sewage, in vegetables and in other food materials is essential to prevent excessive build-up of these metals in the food chain.     

3-Chlorotyrosine formation in ready-to-eat vegetables due to hypochlorite treatment and its dietary exposure and risk assessment

Washing of iceberg lettuce with HOCl solutions in concentrations ranging from 1.41 to 141 mg/L resulted in 0.69 to 2.05 μg 3-chlorotyrosine/g vegetable. As also six commercial ready-to-eat iceberg lettuces from different producers contained 3-chlorotyrosine from 1.00 to 2.24 μg/g vegetable, a total of 122 ready-to-eat vegetable samples purchased in Belgian supermarkets were further screened for their 3-chlorotyrosine content. 3-chlorotyrosine was detected above the detection limit (0.19 μg/g sample) in 97, 24 and 14% of the lettuce mixes, vegetable mixes and frozen vegetables, respectively. In combination with consumption data of ready-to-eat vegetables by Belgian and Spanish consumers, a quantitative exposure assessment was performed, exemplifying a lower and higher ready-to-eat vegetables consuming population. Exposure to 3-chlorotyrosine from the frozen vegetables and vegetable mixes was lower compared to the lettuce mixes due to the combination of lower contamination and lower consumption. 3-chlorotyrosine exposure via lettuce mixes could be considered as a public health concern, especially in higher consuming populations represented by the Spanish population, with 17% of consumers (> 4.2 million people) and 8.5% of the total population (> 2,6 million people) exceeding the threshold of toxicological concern.     

Effects of Holding Methods and Time on the Vitamin Contents of Five Tropical Leafy Vegetables

Five tropical leafy vegetables, Pterocarpus soyauxii (“oha”), Pterocarpus santalinodes (“nturukpa”), Gongronema latifolium (“utazi”), Corchorus olitorius (“ahihiara”) and Amaranthus hybridus (“green”) were held for four days at ambient condition using three different popular local methods used in the Southeastern states of Nigeria. Each leafy vegetable was divided into three lots. Lots I and II were unwrapped while lot III was wrapped with broad cocoyam leaves. The three lots were held under a shade. In addition, lot II was regularly taken outside to the open at nights where it was exposed to cool air and early morning dews. The vitamin contents of each leafy vegetable lot were analysed initially and on daily basis for four days. The beta carotene and ascorbic acid contents ranged respectively from 4.88 – 9.84 μg and 105.62 – 278.65 mg per 100 g of the leafy vegetable. The five leafy vegetables are fair sources of thiamin, riboflavin and niacin. There were losses in the vitamins as holding time increased, regardless of the holding method employed. The rate of loss of vitamins was highest in Lot I (the unwrapped leaves that were kept in a shade both day and night). The rate of loss of vitamins was lowest in Lot III (the wrapped leafy vegetables).     

Effects of repeated exposure to either vegetables or fruits on infant’s vegetable and fruit acceptance at the beginning of weaning

This study investigated the effects of repeated exposure to either vegetables or fruits on an infant’s vegetable and fruit acceptance during the first 18 days of weaning. We hypothesized that repeated exposure to a type of vegetable or fruit, would increase its intake. Furthermore, we expected that being exclusively weaned with vegetables would result in a higher acceptance of vegetables than being exclusively weaned with fruits. To investigate this, a 19-day intervention study was conducted in 101 healthy infants, aged 4–6 months. Infants were randomly assigned to one of four treatment groups. Two groups received exclusively vegetable purées as targets every other day for 18 consecutive days; green beans was the target for one group and artichoke for the other group. The other two groups received exclusively fruit purées including either apple or plums as the target fruit. On day 19, the vegetable groups consumed their first fruit purée and the fruit groups their first vegetable purée. At the beginning of the study on days 1 and 2 and at the end on days 17, 18 and 19, the infants were fed fruit or vegetable purée in our laboratory. On days 3–16, the parents fed their infants the fruit or vegetable purées at home.Outcome variables were vegetable and fruit intake over time. Mean vegetable intake in the vegetable group increased significantly from 24 ± 28 g (mean ± SD) on days 1 and 2 to 45 ± 44 g on days 17 and 18. Fruit intake in the fruit group increased significantly from 46 ± 40 to 66 ± 42 g. Fruit intake was significantly higher than vegetable intake from the start. Repeated exposure to fruit had no effect on the vegetable intake. The first intake of green beans in the fruit groups at day 19, was 24 ± 29 g and on average as low as the green beans intake in the vegetable groups at the 1st exposure on days 1 or 2. Similarly, the first apple intake in the fruit groups on days 1 or 2 of 47 ± 48 g did on average not differ from the first apple intake of 45 ± 49 g in the vegetable groups on day 19. The mean intake of green beans and plums increased significantly after repeated exposure. The intake of the target food artichoke stayed low and the intake of apple only increased slightly. These findings confirm that at the first exposure fruit acceptance is higher than vegetable acceptance. Weaning with vegetables, but not with fruits, may promote vegetable acceptance in infants.