Comparative study on the microbiological quality of vegetables collected from local markets and super shops of Dhaka city

Vegetables are major source of vitamins and fibers but presence of pathogens in salad vegetables can cause outbreak of diseases. Several studies have been conducted on commonly consumed vegetables so far to detect the level of microbial contamination. However, few of them compare the microbial quality of local and super shop vegetables. The present study was conducted for microbiological assessment and comparing four types of vegetables collected from two different market conditions. In this study, Green chili (Capsicum frutescens L.), Tomato (Solanum lycopersicum), Coriander (Coriandrum sativum) and Lady’s finger (Abelmoschus esculentus) were analyzed to determine Total Viable Bacterial (TVB) Counts, Total Fungal (TF) Counts, Total Coliform Counts (TCC), Total Fecal Coliform (TFC) Counts and occurrence of Staphylococcus aureus, Pseudomonas spp., Listeria spp., Bacillus spp., Salmonella spp., and Vibrio spp. Among these microorganisms, Klebsiella spp. and Pseudomonas spp. were significantly present in coriander of both local market and super shop. All pathogenic bacteria and fungi were found in huge amounts in the vegetable samples of the local market. Although some pathogenic bacteria and fungi were also found in the same samples of the super shop, relatively lower than the local market’s vegetables. In conclusion, contamination in collected vegetable samples were not acceptable but comparatively higher load in local market samples indicated that the hygienic condition in these markets is not sufficiently maintained. Stamford Journal of Microbiology, Vol.11 (1) 2021: 24-27

Estimation of Pesticide Residues on Leafy Vegetables Using a Developed Handheld Spectrometer

In this study, a rapid and non-destructive detection model for pesticide residues on leafy vegetables was presented using a developed portable spectrometer. VIS/NIR spectra of three vegetable samples, including lettuce, oriental mustard, and bok choy, were analyzed at the range of 380 – 840 nm. Stepwise multiple linear regression (SMLR) models were developed based on chemical reference measurements and the spectral information of the leaf samples after performing the pre-processing method. Furthermore, a data acquisition interface was developed by Matlab GUI. Results of SMLR procedure indicated good performance for detection of indoxacarb and chlorantraniliprole with R2 ≥ 0.90. A fairly good model (0.90 > R2 > 0.80) was obtained for carbendazim in lettuce, whereas a poor model was found for emamectin-benzoate with R2 ≤ 0.80. It was concluded that pesticide residues on leafy vegetables could be predicted using our developed handheld spectrometer. It can also be generalized for the prediction of other pesticide components in agricultural products.

Distribution of Pesticides in Different Commonly Grown Vegetables of Cameron Highlands, Pahang, Malaysia

Gas chromatography-electron capture detector (GC-ECD) is used to extract and analyse pesticides in vegetable samples collected from Cameron Highlands, Pahang, Malaysia. The limit of detection (LOD) for all pesticides was in the range of 0.03 to 4.5 ng g-1. Recoveries in cabbage, lettuce, and celery ranged from 61.8%-121%, 60-128% and 60%-114%, respectively. The relative standard deviation (RSD) ranged 0.2-15% in cabbage, 0.5-18% in lettuce and 3-19.8% in celery. Organochlorine pesticides (OCPs) concentrations increased down the valley with dichlorodiphenyldichloroethylene (DDE) having the highest concentration at 233 µg kg-1. Organophosphorus pesticides (OPPs) were found to be dispersed throughout the valley, with the highest concentration of parathion ethyl (133 µg kg-1) whereas the pyrethroid pesticides (PYRs) concentrations were comparatively less. The detection frequency in the wet season was highest (5 < - < 100 µg kg-1) for most pesticides. However, in the dry season the pesticides concentrations were higher, at < 5 µg kg-1. PCA analysis indicated that farmers were using a mixture of pesticides.

Microbial quality and labeling of minimally processed fruits and vegetables

The consumption of minimally processed, or ready-to-eat (RTE), fruits and vegetables has been growing because people have shorter time to eat and due to the pursuit of convenience and health benefits. Minimal processing includes raw material selection and sorting, pre-washing, debarking, cutting, slicing, sanitizing, rinsing, centrifuging, and packing. Thus, natural protection barriers are affected during cutting methods and they release nutrients that enable microorganism growth. The aim of the current study was to evaluate the levels of aerobic mesophilic bacteria, molds and yeasts, coliforms at 35°C, Escherichia coli and Salmonella sp., as well as the labeling adequacy of minimally processed fruits and vegetables traded in Vitória, Espírito Santo, Brazil. Fruits and vegetables presented aerobic mesophilic bacteria, molds and yeasts, and coliforms at 35°C, above the safe limit for consumption purposes. The count of aerobic mesophilic bacteria in RTE fruits ranged from 4.00 to 6.30 Log CFU/g. The highest count of this microorganism group was recorded for fruit salads. Salmonella sp. was not identified in fruit or vegetable samples, whereas Escherichia coli was detected in four vegetable samples. None of the evaluated labels (n = 40) followed the Brazilian legislation. Minimally processed fruits and vegetables had poor microbiological quality and labeling was also unsatisfactory. The adoption of good manufacturing practices and quality control tools as strategies to produce safe food can help minimizing risks to consumers’ health.

A PRELIMINARY ALGERIAN STUDY OF CONTAMINATION ASSESSMENT FOR PATHOGENIC INTESTINAL PARASITE IN FRESH VEGETABLE

Fresh vegetables are frequently used to prepare fresh salad dishes widely consumed in the world. They are known to be the main source of pathogenic intestinal parasites. In this context, the present work aimed to (a) detect the pathogenic intestinal parasites (PIP) in washed fresh vegetables, and (b) assess the exposure to PIP in the city of Ain Témouchent (Algeria). In fact, 26 samples belonging to six groups of fresh vegetables (cabbages, lettuces, leeks, radishes, peppers and tomatoes) were collected, washed (similarly to domestic wash with or without vinegar addition), then examined for PIP contamination. The results indicated that 90% of the examined vegetable samples were contaminated with intestinal parasites showing higher prevalence in lettuce (70.85%) while the lowest contamination (23.52%) was reported in pepper. In addition, Cryptosperidium (72%) has been found to be the most dominant parasite in all vegetables while Toxocara (8%) was less present. These finding are a preliminary report to conduct a risk assessment of PIP linked to vegetable feeding

Determination of Concentration of Heavy Metals in Fruits, Vegetables, Groundwater, and Soil Samples of the Cement Industry and Nearby Communities and Assessment of Associated Health Risks

This study was conducted to estimate the heavy metal pollution in groundwater, soil, fruits, and vegetables within the cement industry and its vicinity. Seven different fruits and vegetables and seven heavy metals (Cd, Zn, Ni, Co, Cu, Cr, and Mn) were selected for analysis in soil, groundwater, fruit, and vegetable samples by atomic absorption spectrometry (AAS). Results of this study were compared with the National and International Standards of Pak NSWQD, WHO, and USEPA. The pH of soil and groundwater samples was within limits (WHO and Pak NSDWQ standards are 6.5–8.5). The concentration of Cr and Cu in groundwater samples was above the WHO and Pak NSDWQ standards (Cr = 0.05 ppm; Cu = 2 ppm). Vegetable samples were contaminated with metals except for Ni and Mn, whereas, in fruit samples, Mn and Cd were not present (WHO limit for Mn = 5 ppm). The mean concentration of Ni was high in fruits (WHO limit = 10 ppm), Zn was high in vegetables (WHO limit = 100 ppm), and Cu was high in soil and groundwater (WHO limit for soil = 36 ppm; for groundwater = 2 ppm). The results of daily intake of metals (DIM) for fruits, vegetables, and groundwater were compared with TDI by USEPA and PTDI of the WHO/FAO, and all were within the recommended limits. Calculated BAF for the selected environmental sample, that is, Indian Squash, lime fruit, and so on, was in order of Co > Cr > Cu and THQ; HRI was calculated to estimate the human health risk, and they were in a trend of Ni > Co > Cd > Cr and for HRI Co > Cr.

Estimation of coefficient of performance of thermoelectric cooler using a 30 W single-stage type

In this study, a single stage thermoelectric cooler (TER, of size: 21 × 14.2 × 13.5 cm) with thermoelectric module (TEM, of type inbc1-127. 05 with size 40 × 40 × 4.0 mm) and applied electrical power of 30 W and current of 2.5 A, was adopted to estimate the coefficient of performance (COP) of thermoelectric refrigerator (TER). The TER uses a fan to cool the heat exchange region of the TEM. The temperature of the fruit/vegetable samples used in this study was taken before and after cooling for a specific period. The temperatures at both the hot and cold sides of the TEM were also taken at every specific cooling period. The experimented TER can cool vegetable/fruit from about 27 to 5°C within 3 h. The aim of this study is to determine the COP of TER to ascertain the possible applications. The temperature gradient at the heat exchange section of TEM was used to estimate the average theoretical COP to be 0.99, the heat extracted from the cooling chamber and the power supplied was used to estimate the average practical cooling COP to be 0.52; which is within 0.4–0.7 standard COP for a single stage type of TER.