Assessment of parasitic contamination of raw vegetables in Mannuthy , Kerala state , India

Aim: To assess the parasitic contamination of raw vegetables retailed at Mannuthy in Thrissur district of Kerala state, India. Materials and Methods: A total of 112 samples, viz. cabbage (17), mint (11), coriander leaves (11), spinach (15), onion (10), carrot (10), potato (10), ginger (15), beet root (7) and tomato (6) were collected from retail market at Mannuthy, Kerala. Collected samples were washed with physiological saline solution. The washings were collected and examined under light microscopy. Results: Helminthic eggs were detected in three (2.7%) of 112 samples. Two samples of cabbage (1.8%) and one sample of onion (0.9%) was positive for ova of Ascaris spp. Conclusion: Vegetables can act as potential source of gastrointestinal parasitic infections. The study emphasizes the need for proper washing of vegetables before they are consumed or cooked.


Introduction
source of food borne outbreaks in developing countries [5].Consumption of unwashed, raw, and unhygienically Vegetables are essential for human health and prepared vegetables is considered a risk factor for well-being, and they form a major component of human parasitic infections.There has been an increase healthy diet.They are highly beneficial for maintenance in the number of reported cases of food-borne illness of health and prevention of diseases [1].Vegetables linked to fresh vegetables [6].contain valuable nutritional factors, which can be Keeping these facts in mind, the present study successfully utilized to build up and repair the body.
was conducted to assess the parasitic contamination of They are valued mainly for their high carbohydrate, raw vegetables, retailed at Mannuthy in Thrissur vitamins, minerals, and fibre contents.Joint FAO/ district of Kerala state, India.The findings could lead to WHO Expert Consultation on diet, nutrition and the better practices in handling, washing, and preparation prevention of chronic diseases, has recommended the of vegetables to protect the consumers against gastrointake of a minimum of 400g of vegetables and fruits intestinal parasitic infections.per day for the prevention of chronic diseases such as heart disease, cancer, diabetes and obesity, as well as for
from retail market at Mannuthy during January-On the other hand, vegetables can act as potential March, 2012.The samples (approximately 100 g) were source for the spread of various infectious and parasitic collected in sterile plastic bags (30 x 20 cm) and diseases [3].Parasitic diseases can be considered examined for helminthic eggs as described previously among the most common diseases on earth, which are [7].Samples were washed with physiological saline transmitted to humans through water, soil, and foodstuffs solution (0.85% NaCl).The washing water was left for such as vegetables [4].Vegetables, especially salads, 10h for sedimentation to take place and then the top are an important route of transmission of intestinal layer was discarded and the remaining was centrifuged parasites and have been shown to be an important at 2164 g for 15 min.The supernatant was discarded, the residue was carefully collected and examined in lugol stained slides (three for each sample) through light microscopy and eggs were identified.

Results
processing, and preparation by handlers including consumers also contribute in vegetable contaminations Distribution of parasitic ova on vegetables in the [16].study is presented in Table -1

. Of the 112 samples
In the present study, it was found that cabbage and screened, three were positive for helminthic ova, all for onion are contaminated with parasitic ova.These Ascaris spp.ova.Two samples of cabbage (1.8%) and vegetables are commonly consumed raw and are one sample of onion (0.9%) was positive for Ascaris important components of salads.Therefore, the study spp.ova.
points to the need for proper washing and disinfection Discussion of all vegetables, particularly salad vegetables and those that are consumed raw.In a study conducted in Detection of helminthic ova on raw vegetables in West Bengal, India, 44.2% of vegetables in the study the present study has significant public health were positive for helminthic ova.Ascaris spp.eggs implication.Vegetables may act as passive vehicles for were the most predominant parasitic ova observed and transmission of pathogenic parasites and protozoa that was detected in 36 per cent of the samples examined are primarily transmitted through the fecal-oral route [17].In another study, conducted in Morocco, 50% of [8].Worldwide, parasites infect millions of people.In vegetables from farmland were contaminated by some regions, there are a major cause of childhood helminthic eggs [18].Adamu et al. conducted a study in diarrhoea and stunting of growth and cause significant Northeastern Nigeria and found that 3.5% vegetables economic losses related to human and animal health were contaminated with helminthic parasites [19].and to agriculture [9].Intestinal parasites are widely Kozan, et al. [20], reported zero percent prevalence of prevalent in developing countries, probably due to poor helminthic eggs in washed vegetables in Turkey [20].sanitation and inadequate personal hygiene [10].
[21], reported a parasitic prevalence of Studies conducted in both developed and developing countries have shown that helminthic diseases caused 40 per cent and 76% in markets vegetables and gardens by Ascaris spp.and Trichuris spp.and bacterial vegetables respectively in Tabriz, Iran.Olyaei and diseases such as cholera are endemic in populations Hajivandi [22] reported parasitic contamination of that consume salad vegetables irrigated with raw or 38.5 and 48.9% in markets vegetables and gardens untreated sewage [11].Biologically, the highest health vegetables respectively in Southern Iran [22].Saki et risk is for helminthic infections compared with other al.
[23] reported that 15.5% of studied vegetables in pathogens because helminthes persist for longer Ahvaz, southwest of Iran, were contaminated with periods in the environment and the infective dose is various parasite stages [23].Geographical location, small [12].Continued use of untreated wastewater and type, and number of samples examined, methods used human and animal excreta as fertilizer for production for detection of the intestinal parasites, type of water of fruits and vegetables is a major contributing factor used for irrigation, and post-harvesting handling for contamination that causes numerous food-borne methods of vegetables are different from country to disease outbreaks [13].Ascaris spp.ova are found in country and region to region.This could be the reason insufficiently treated sewage-fertilizer and in soils for variation in prevalence in different parts of world where they may contaminate crops grown in soil or [24].fertilized with sewage.The eggs of these roundworms Enquiry with the retailers revealed that the are 'sticky' and may be carried to the mouth by hands, vegetables are not cultivated in the same locality, but inanimate objects or foods, transmission may also be are imported from other nearby states.In such caused by contamination of a wide variety of foods by vegetable gardens, there are possibilities for the use of infected food-handlers [14].Contamination of soil with night soil or untreated sewage as fertilizers, which animal wastes and increased application of improperly might have contributed to the presence of Ascaris spp.composted manures and improperly treated wasteova in 2.7% of examined vegetables.Ascaris spp.water to soil in which vegetables are grown also play a (roundworm) is among the resistant enteric pathogens role in parasite contamination to green vegetables [15].and it is often used as a parasitological indicator [25] Bad hygienic practice during production, transport, and affects about a quarter of the world's population but more prevalent in the developing world [26].Samples at retail markets in Mannuthy, are contaminated with of cabbage revealed a prevalence of 1.8% and onion pathogenic helminthic parasites and may pose a health samples recorded a prevalence of 0.9%.Variation in risk to consumers of raw vegetables.The present study prevalence rates of parasitic contamination among the emphasizes the importance of raw vegetables in different vegetables could arise due to differences in threatening public health by transmission of intestinal plant foliage [19].Vegetables like cabbage have broad parasites to humans.The findings of the study may leaves and large surface areas, which are in direct have important implications in food safety and points contact with the sewage contaminated soil surface [27].
to the need for further investigation in this area.Cabbage also has rough uneven surfaces that make Prevention of contamination is the most efficient parasitic eggs attach themselves easily to the surfaces way to ensure food safety and prevent foodborne of the vegetables either on the farm or when washed illness.Thus, every effort should be made to protect with contaminated water [28].These could be the food from primary sources of contamination.reasons for detection of parasitic ova in samples of Prevention of infection can be achieved by thorough cabbage.Vegetables like tomatoes have smooth washing of vegetables, improved hygienic practices of leathery surfaces that tend to reduce the rate of parasitic vegetable handlers and improvement in standards of attachment [29].
sanitation.The local health authorities should take Vegetables pass through several hands on their necessary actions to improve the sanitary conditions in way from farm to the table.During this period, they can the areas where the vegetables are cultivated.become contaminated with enteric bacterial, viral, and Construction of sanitary toilets for farm workers and parasitic pathogens throughout the process of planting provision of safe and wholesome water is also to consumption [24].Contamination can occur on field recommended.Passage of animals across vegetable during growth, harvesting, transportation, processing, farms must be restricted through proper farm fencing.distribution, and marketing or in home by food Use of properly treated manure and proper treatment of handlers.Once harvested, vegetables may be washed wastewater used for irrigation of vegetables should be in nearby canals, which may also add parasitic implemented.There is also an urgent need for the contamination.Such water bodies may carry parasitic improvement of sanitary facilities in our markets and ova excreted through feces of infected animals and vegetable vendors.human beings.According to Ebrahimzadeh et al, in However, this may not be possible always and raw most cases, contamination of raw vegetables is foodstuffs, particularly fruits and vegetables grown associated with the water used for irrigation [30].
close to the soil, may be contaminated with various Mahvi et al. [31], reported that use of insufficiently pathogens.In such cases, efforts should be made to treated wastewater to irrigate vegetables is responsible establish critical control points to reduce for the high rates of contamination with pathogenic contamination to safe levels, by applying the Hazard parasites in many developing countries.
Analysis and Critical Control Point system.Awareness The maximum and minimum atmospheric on potential health consequences of consumption of temperature during sampling period was in the range of contaminated foodstuffs must be created among public 29-37°C and 17-26°C.Average relative humidity through various media.Education of public on steps to during the period was around 70%.These conditions be taken for prevention and control of food borne favour the survivability of parasitic ova and pose threat illness is also vital.to the consumers.Kim et al, [32], reported that, temperature in the range of 25-35 °C accelerates the development and embryonation of Ascaris spp.eggs.BS (Principal Investigator of the project) and CL Ascaris spp.eggs are of particular interest in that the designed the study.DRT and HS: collection of samples presence of a thick cell wall makes them resistant to and laboratory analysis.All authors have contributed in adverse environmental conditions and provide them a drafting and revision of the manuscript.All authors long life span in the soil [33].Temperature, relative read and approved the final manuscript.humidity and light affect the viability of eggs which, in The result of this study has indicated that vegetables (2006) Use of vegetables as nutritional food: role in human

Table - 1
: Distribution of parasitic ova on vegetables in the study