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Abstract
J HEALTH POPUL NUTR 2014 Sep;32(3):391-399 ©INTERNATIONAL CENTRE FOR DIARRHOEAL ISSN 1606-0997 $ 5.00+0.20 DISEASE RESEARCH, BANGLADESH Microbial Evaluation of Fresh, Minimally-processed Vegetables and Bagged Sprouts from Chain Supermarkets 1 1,2 1 3 Maryam Zare Jeddi , Masud Yunesian , Mohamad Es’haghi Gorji , Negin Noori , 4 1 Mohammad Reza Pourmand , Gholam Reza Jahed Khaniki Department of Environmental Health Engineering, School of Public Health, Tehran University of Medical Sciences, Poorsina Street, PO Box 14155-6446, Tehran, Iran; Center for Air Pollution Research, Institute for Environmental Research, Tehran University of Medical Sciences, Kargar Street, Gol Building, Tehran, Iran; Department of Food Hygiene, Faculty of Veterinary Medicine, University of Tehran, Azadi Street, Tehran, Iran; Department of Pathobiology, School of Public Health, Tehran University of Medical Sciences, Poorsina Street, Tehran, Iran ABSTRACT The aim of this study was to evaluate the bacterial and fungal quality of minimally-processed vegetables (MPV) and sprouts. A total of 116 samples of fresh-cut vegetables, ready-to-eat salads, and mung bean and wheat sprouts were randomly collected and analyzed. The load of aerobic mesophilic bacteria was mini- mum and maximum in the fresh-cut vegetables and fresh mung bean sprouts respectively, corresponding to populations of 5.3 and 8.5 log CFU/g. E. coli O157:H7 was found to be absent in all samples; howev- er, other E. coli strains were detected in 21 samples (18.1%), and Salmonella spp. were found in one mung bean (3.1%) and one ready-to-eat salad sample (5%). Yeasts were the predominant organisms and were found in 100% of the samples. Geotrichum, Fusarium, and Penicillium spp. were the most prevalent molds in mung sprouts while Cladosporium and Penicillium spp. were most frequently found in ready-to-eat salad samples. According to results from the present study, effective control measures should be implemented to minimize the microbiological contamination of fresh produce sold in Tehran, Iran. Key words: Foodborne pathogen; Fungal contamination; Microbial safety; Mold; Sprouts; Iran INTRODUCTION minimally-processed fruits and vegetables have increased in the recent years due primarily to In many parts of the world, including Iran, there transmitting various pathogens to humans (4,5). is an increasing rate of consumption of raw fresh Contamination of these products by pathogenic produce, like vegetables, fruits, and sprouts. This is microorganisms, specifically in leafy green vegeta- especially the case for minimally-processed fruits bles, poses serious health threats to consumers (6). and vegetables, mainly because of changes in the Freshly-consumed produce can be contaminated human lifestyle and their tendency towards con- with pathogens via being exposed to contamina- venience and spending less time on preparing tion sources from production on the farm to the food (1-3). However, despite their nutritional and point of sale in the market (7). These reported con- healthy characteristics, outbreaks of human infec- tamination sources are: soil (e.g. manure, faeces, soil tions associated with the consumption of fresh or microorganisms), dust, water, and handling during pre- or postharvest stages (8). The major sources Correspondence and reprint requests: of postharvest contamination are containers used (Reprints are not available from the authors) for transporting the produce, human handling, Dr. Gholam Reza Jahed Khaniki processing, and storage (9). Avoidance of decon- Department of Environmental Health Engineering School of Public Health taminating measures before consumption also Tehran University of Medical Sciences predisposes fresh produce to remain contaminated Poorsina Street with potential human pathogens (10). Moreover, PO Box 14155-6446 minimally-processed fruits and vegetables are more Tehran, Iran susceptible to contamination because cutting and Email: [email protected] slicing damage the natural protective barriers of the Fax: +98 2188950188 Microbial safety of ready-to-eat vegetables Jeddi MZ et al. intact produce and release nutrients and facilitate rots, and tomato), 64 sprout samples (mung and growth of microorganisms (1,11,12). wheat), and 32 samples of fresh-cut vegetables (including seven types of vegetables: Leek, fennel, Outbreaks of foodborne diseases linked to the con- watercress, basil, and radish). All of the samples sumption of fresh produce have shown a remarka- were obtained in the original packages before their ble increase in the last two decades (13). The Center best-before date, within the shelf-life of up to seven for Science, in the public interest, recently released days, as mentioned on the labels. All samples were a report based on the data from the Centers for placed in secure sterile re-sealable plastic bags and Disease Control and Prevention (CDC) and other transported promptly to the laboratory in ice box- sources, indicating that green leafy vegetables were es. Samples that had been unpackaged or visibly associated with 363 outbreaks, including 13,569 damaged were discarded before analysis. announced cases of illness (14). An outbreak of E. coli O157:H7 occurred in 26 US states in September Bacteriological analysis 2006, which led to about 200 cases of illness, in- Manufacturer’s name, type of vegetables, batch cluding some with haemolytic-uraemic syndrome number, expiry date, and the type of packaging (HUS) and resulted in three deaths (15). Data dem- (modified or non-modified atmosphere) were re- onstrated that fresh spinach grown in three Califor- corded. The surfaces of the packaging were steri- nian counties was responsible for contamination. lized before samples were taken out of them. This Salmonella is the leading cause of foodborne diseas- was done using ethanol-sterile gauze to prevent es throughout the world. In the last few years, out- cross-contamination. breaks of Salmonella have been linked increasingly to consumption of fresh vegetables. This pathogen Ten grammes of each sample was weighed and is the main challenge for the microbiological safety placed in a stomacher bag, and it was diluted in of MPV (16). 90 mL of buffered peptone water (BPW) and ho- mogenized for 2 min at 260 rev per minute, using a Microbiological surveys of MPV products have in- stomacher (Model 400 circulator, Seward, Norfolk, vestigated the occurrence of Salmonella, Escherichia England). Eight decimal dilutions of the suspension coli, coliforms, total aerobic and spoilage bacteria, were made in BPW and analyzed for aerobic mes- fungi, and yeasts (1,17-22). Most reported counts ophilic count, E. coli, coliforms, molds, and yeasts. for total aerobic bacteria ranged between 4 and 8 log CFU/g and between 0.7 and 6 log CFU/g for For determination of aerobic mesophilic bacteria, coliforms. E. coli strains have been often observed 1 mL of each decimal dilution was added to 12-15 at low prevalence and low counts. Pathogens, like mL plate count agar (PCA), the plates were incu- E. coli O157:H7, Salmonella, and L. monocytogenes, bated for 24-48 h in 30 °C, and then the bacterial have rarely been found. colonies were counted (23). To the best of our knowledge, there is no published To detect Salmonella spp., 25 g of each sample was data on the microbiological quality of this fresh diluted in 225 mL of BPW and homogenized as pre- produce in Iran. Therefore, this study represents viously described. Then, these were held for 16-24 the first survey in microbial contamination in MPV h at 35 °C; 0.1 mL of this sample was added to two and sprouts. The aim of this study was to investi- broth cultures (Selenite cysteine and Tetrathionate gate the microbiological quality (both bacterial and broth) that contained iodine and novobiocin, then fungal contamination) in MPV and sprouts, which was incubated at 35 °C and 41.5 °C for 24 h respec- are commercially available in Iran, aiming at the tively. For isolation and identification, streaking future improvement of food safety measures. cultures from two mentioned cultures were done by three differential cultures, including brilliant green MATERIALS AND METHODS bile broth (BGBB), xylose lysine deoxycholate agar (XLD agar) and Salmonella-Shigella agar (SSA) and Collection of samples incubated for 24-48 h at 37 °C; 1-2 colony(ies) were A total of 116 samples of MPV and bagged sprouts picked up from each positive plate and cultured on were randomly collected from four chain super- three media (Lysine decarboxylase agar triple, sugar markets during May and July 2012 in Tehran city, iron agar, and urea broth) to be confirmed (24). Iran. Vegetables and sprouts comprised 20 samples of ready-to-eat salads (containing three to five in- For determining the coliforms, 1 mL of each decimal gredients, such as lettuce, coleslaw, cucumber, car- dilution and 15 mL solid culture medium of violet JHPN 392 Microbial safety of ready-to-eat vegetables Jeddi MZ et al. red bile agar (VRBA) were poured to petridish; after Statistical analysis stirring, these were held to fix. Then a thin layer of All of the samples were tested in triplicate. Statis- media were poured to make micro-aerophilic condi- tical analyses were estimated using SPSS (version tion, and plates were incubated for 24 h at 35 °C; 11.5). In order to analyze the data, standard de- in the end, red colonies were counted (25). Also, viation and mean were calculated. Independent presumptive E. coli was determined. At first, 1 mL of t-test were used for determining any statistically primary dilution was added to lauryl sulphate media significant difference (p<0.05) among two brands and incubated at 37 °C for 24 h; if the gas was ob- of each commodity. served, loopfuls of suspension were transferred to EC broth and kept at 44 °C for 48 h to examine for gas RESULTS production; gas-positive samples were transferred to PBW to keep at 44 °C for 48 h; indol production was Aerobic mesophilic count confirmed by using indol reagent, which resulted Table 1 presents the contamination of fresh- in red colour that verified presence of E. coli. Differ- cut vegetables, ready-to-eat salads, and wheat and entiation of E. coli was carried out with IMViC test. mung sprouts to aerobic mesophilic bacteria; the E. coli strains isolated were plated in Tergitol BCIG average loads were 6.4±0.7, 6.7±0.5, 6.9±0.6, and agar and Sorbitol-MacConkey agar and incubated 7±0.6 log CFU/g respectively. at 44±1 °C for the detection of β-glucuronidase and sorbitol-positive strains respectively (26). Coliforms, E. coli, and Salmonella spp. For determination of yeasts and molds, 1 mL of The number of total coliforms and pathogens in each decimal dilution was placed on plate surface the vegetables and sprouts are presented in Table that contained Sabouraud dextrose agar (SDA) and 2 and 3. As presented in Table 2, total coliforms distributed by a sterilized swab. Plates were incubat- were not detected in 13% of the fresh-cut vegetable ed for 5 days at 25 °C. Colonies were counted and samples while the rest of the samples were positive. expressed as CFU/g; molds were purified on SDA Mung bean sprout samples contained the highest for further subculture for microscopic examination values of thermotolerant coliforms with a mean of and identification (27). 62.5%. Table 1. Aerobic mesophilic counts in examined samples of fresh, minimally-processed vegetables and bagged sprouts Percentage of samples in the indicated interval No. of b 7 6 7 5 6 5 a* Mean Range >10 10 -10 10 -10 <10 Food item samples 7.0±0.6 6.4-8.5 43.8 56.2 0.0 0.0 32 Mung sprouts 6.9±0.6 5.5-8.4 43.7 50.0 6.3 0.0 32 Wheat sprouts 6.7±0.5 5.5-7.4 25.0 70.0 5.0 0.0 20 Ready-to-eat salads 6.4±0.7 5.3-7.5 18.8 53.1 28.1 0.0 32 Fresh-cut vegetables *Results are expressed as mean±SD of three repetitions; Counts are given in terms of log CFU/g of prod- ucts; Range in log CFU/g of products Table 2. Total coliform counts in fresh, minimally-processed vegetables and bagged sprout samples obtained from chain supermarkets Percentage of samples in the indicated interval No. of a b 5 4 5 3 4 2 3 2 Mean Range >10 10 -10 10 -10 10 -10 <10 Food item samples 4.0±0.9 ND -5.5 15.6 28.1 31.3 9.4 15.6 32 Fresh-cut vegetables 4.7±1.0 2.8-6.5 34.4 40.6 15.6 9.4 0.0 32 Wheat sprouts 4.5±1.1 2.7-6.4 34.4 31.2 31.2 3.2 0.0 32 Mung sprouts 4.0±1.3 1.9-6.0 30.0 20.0 25.0 20.0 5.0 20 Ready-to-eat salads Results are expressed as mean±SD of three repetitions and the counts are given in terms of log CFU/g of b c product; Range in log CFU/g of products; Not detected | | Volume 32 Number 3 September 2014 393 Microbial safety of ready-to-eat vegetables Jeddi MZ et al. E. coli was detected in 3 out of 32 fresh-cut vegeta- spp., which were found in 25%, 15.6%, and 10.9% ble samples (9.4%), in 6 out of 20 ready-to-eat sal- of the samples respectively (Table 5). Among the ad samples (30%), and in 12 of 64 sprout samples commodities, wheat sprouts (Geotrichum and (18.7%) (Table 3). Fusarium spp.), mung sprouts (Geotrichum and Penicillium spp.), and ready-to eat vegetables Salmonella spp. were not detected in fresh-cut veg- (Cladosporium and Penicillium spp.) constituted etables and wheat sprouts but it was isolated from 1 the most prevalent molds, and ready-to-eat salads out of 20 ready-to-eat salad samples (5%) and 1 out generally contained greater values of molds than of 32 mung bean sprout samples (3.1%) (Table 3). fresh-cut vegetable samples. Cladosporium, Penicil- lium, Alternaria, and Geotrichum spp. were the most Yeasts and molds common filamentous fungi in ready-to-eat salad The results of mold and yeast counts are presented samples and were present in 35%, 20%, 15%, and in Table 4. Yeasts were the predominant organisms 15% respectively. and found in 100% of the samples. Molds and DISCUSSION yeasts in fresh-cut vegetables, ready-to-eat salads, and sprout samples were in the range of 5.4-7.6, Microbial quality of fresh, minimally-processed 6.2-7.5, and 6.0-8.5 log CFU/g respectively. Yeast vegetables and bagged sprouts obtained from chain populations were more than 10 CFU/g in the en- supermarkets in Tehran city of Iran was determined. tire ready-to-eat salads and sprout samples. In com- In this study, significant differences were not ob- parison, fresh-cut vegetables generally contained served among commercial brands. With respect to less amounts of yeasts, with 78% of the samples the national standards of Iran (28), only 3% of the having counts of <10 CFU/g (Table 4). sprout samples (mung sprout and wheat germ), Majority of the samples showed molds contami- 28.1% of the fresh-cut vegetable samples, and 5% 2 4 nation levels between 10 and 10 CFU/g. The of the ready-to-eat salad samples, which contained most frequent molds observed in sprout samples less than 6.0 log CFU/g aerobic mesophilic bacte- comprised Fusarium, Penicillium, and Geotrichum ria, can be considered safe for consumption. The Table 3. Percentage of bacterial groups present in fresh, minimally-processed vegetables and bagged sprout samples from chain supermarkets Salmonella Thermotolerant No. of E. coli Total coliforms Food item spp. coliforms samples ND 9.4 34.4 87.5 32 Fresh-cut vegetables ND 21.9 53.1 100.0 32 Wheat sprouts 3.1 15.6 62.5 100.0 32 Mung sprouts 5.0 30.0 45.0 100.0 20 Ready-to-eat salads Not detected Table 4. Mold and yeast counts in fresh, minimally-processed vegetables and bagged sprout samples from chain supermarkets Percentage of samples in the indicated interval a b 8 7 8 6 7 5 6 5 Mean Range >10 10 -10 10 -10 10 -10 <10 No. of samples Food item 6.9±0.6 6.3-8.5 9.4 31.2 59.4 0.0 0.0 32 Mung bean sprout 6.8±0.6 6.0-8.4 6.2 37.5 56.2 0.0 0.0 32 Wheat sprouts 6.7±0.4 6.2-7.5 0.0 40.0 60.0 0.0 0.0 20 Ready-to-eat salads 6.4±0.6 5.4-7.6 0.0 18.7 59.3 22 0.0 32 Fresh-cut vegetables Results are expressed as mean±SD of three repetitions and the counts are given in terms of log CFU/g of product; Range in log CFU/g of product JHPN 394 Microbial safety of ready-to-eat vegetables Jeddi MZ et al. Abadias et al. (1) reported that the average count Table 5. Frequency of fungi isolation in fresh, of aerobic mesophilic bacteria in 236 samples of minimally-processed vegetables and fresh-cut vegetables was in the range of 4.3 to 8.9 bagged sprout samples from chain su- log CFU/g. In another study, the microbial quality permarkets of fresh-cut vegetables and fruits was evaluated by Frequency Gómez-Govea et al. (2). The results indicated that Range (% con- the levels of mesophilic organisms ranged from 10 Organism (log CFU/g) tamination to 10 CFU/g. samples) As mentioned on the labels of sprouts and fresh-cut Fresh-cut vegetables (32 samples) vegetables, it is recommended to wash these prod- Cladosporium <100-4.7×10 21.9 ucts before consumption. Our analysis showed 2 3 Penicillium 1.4×10 -1.6×10 15.7 that the maximum reduction of 0.5 log CFU/g in 3 the microbial load is achieved after this washing Alternaria <100-3.5×10 12.5 step, which was not remarkable (data not shown). Geotrichum <100-2.8×10 6.2 Because salads are directly used, appropriate and Trityracium 2×10 -2.5×10 3.1 effective washing could not play a substantial role Aspergillus <100-3×10 6.2 in decreasing the microbial load and caused a max- imum of 2 log CFU/g reduction in the fresh-cut Wheat sprouts (32 samples) vegetables (30). Cladosporium <100-4×10 15.6 Penicillium <100-3.7×10 9.4 Due to the favorauble conditions present in sprout samples, including high humidity, high tempera- Alternaria <100-1.9×10 9.4 tures, and suitable pH and nutrients, microbial Geotrichum <100-4.5×10 21.9 population can proliferate fast, especially during Rhizopus <100-2.4×10 6.2 sprouting (29,31). Martínez-Villaluenga et al. (31) Fusarium <100-9×10 12.5 evaluated the role of germination in the micro- Mung bean sprouts bial loads of broccoli seeds and reported that the 3 amount of aerobic mesophilic bacteria, total and Cladosporium <100-4.2×10 12.5 thermotolerant coliforms increased approximately Penicillium <100-1.7×10 12.5 by 2 and 3 log CFU/g after five days of germination Alternaria 100-1.8×10 3.1 respectively. Hence, these products are exposed to Geotrichum <100-3.8×10 28 higher pathogenic contamination, such as E. coli and Salmonella spp. compared to vegetables. There- Rhizopus <100-2.6×10 9.4 fore, preventive technical approaches should be Fusarium <100-5.2×10 18.7 implemented to ensure safety of sprouts (32). Ready-to-eat salads (20 samples) de Oliveira et al. (21) assessed the microbial quality Cladosporium <100-1.3×10 35 of 162 MPV samples and detected E. coli in 53.1% of Penicillium <100-2.6×10 20 the samples, Salmonella spp. in 1.2% of the samples, Alternaria <100-4.4×10 15 and total and thermotolerant coliforms in 81.5% Geotrichum <100-3.3×10 15 and 66% of the samples respectively (21). Seow et al. (29) mentioned that the average load of coliforms Trityracium <100-7×10 10 3 in 13 ready-to-eat salad samples and 14 bean sprout Aspergillus 100-2.4×10 5 samples were 5.2 and 5.7 log CFU/g respectively, average count of aerobic mesophilic bacteria ob- and all samples contained populations greater than served in this study was similar to that observed by 4 log CFU/g. Aycicek et al. (7) pointed out that there Seow et al. (29) who reported that the mean count are some factors influencing high load of coliform of aerobic mesophilic (6.5 log CFU/g) ranged from in leafy vegetables, including large surfaces exposed 5.8 to 7.3 log CFU/g, in 13 packs of salad. Similarly, to contamination, intense use of untreated manure Valentin-Bon et al. (20) conducted a study under during preharvest, and more handling steps during the supervision of Food and Drug Administration postharvest. In the present study, the population (FDA) in the United States (USA) on 100 bagged let- of total coliforms in 95% of the samples exceeded tuce and spinach mixes and revealed that the aver- 2 log CFU/g (national standard). In spite of the age count of aerobic mesophilic bacteria was 7 log absence of E. coli O157:H7 in the samples of this CFU/g, ranging from <4 to 8.3 log CFU/g. study, E. coli strains were detected in 9.4% of fresh- | | Volume 32 Number 3 September 2014 395 Microbial safety of ready-to-eat vegetables Jeddi MZ et al. cut vegetable samples, in 30% of ready-to-eat salad vegetable samples, ranging from 4 to 7 log CFU/g. Acevedo et al. (40) also detected molds in the levels samples, and in 18.7% of sprout samples. Also, E. of 4.5×10 CFU/g in salad samples. They reported coli O157:H7 has not been isolated in several studies the frequent presence of Penicillium, Aspergillus, and (1,2,18,22,29). The prevalence of E. coli found in the Fusarium spp. in salads. Although organisms, such present study was lower than that in the study by as Rhizopus stolonifer and Paecilomyces, were found Prado et al. (33), that reported E. coli contamination at low levels in sprout samples, these can grow fast in 30% of the MPV samples. Based on a report by and cause spoilage in short time. In addition to the Abadias et al. (1), E. coli contamination was found differences in local sanitary conditions from farm in 7.1% of the whole vegetable samples and 11.4% to the market, various methodologies used in these of the fresh-cut vegetable samples; only two fresh- studies could yield different results. cut vegetable samples (0.8%) had E. coli counts ex- ceeding 100 MPN/g. In another study (34) on faecal Many of the isolated molds belonged to toxigenic indicator in fresh produce, E. coli strains were iden- genera, such as Penicillium, Alternaria, and Fusarium tified in 8.1% of carrots, lettuce, green onions, and spp. The high numbers of Penicillium spp. in bean spinach samples. sprout samples and their ability to grow at refrig- eration temperatures indicate a potential for my- In several similar studies on the microbial quality cotoxin production of these foodstuff during mar- of vegetables, E. coli and Salmonella spp. were either keting (19). According to some authors, the high not detected in any of the samples, or these were de- density of mycotoxin-producing molds generally tected in only one sample (2,22,29,35). Salmonella correspond to poor cleaning practices and/or use of contamination in this study is low when compared unhygienic techniques and contaminated equip- with the results of the study by Bruno et al. (36) ment (16,41). who evaluated the microbial quality of samples of MPV commercialized in northeast Brazil (46.7%). Cantwell and Kasmire (42) referred a significant in- However, our results are consistent with those crease in the number of bacteria during the cutting of the study by Fröder et al. (17) who worked on process, automatic filling, and packaging lines of minimally-processed leafy vegetables commercial- lettuce. It seems that a clean product can be re- ized in São Paulo, Brazil (3%). In a study conducted infected after passing through stages in which there by Viswanathan and Kaur (37) on 120 samples of is the possibility of remaining vegetables, such as fresh vegetables, fresh-cut fruits, and sprouts, faecal cutting, filling in equipment, and packaging. Sev- E. coli strains were verified in 31.9% of vegetables eral studies conducted on the production of these and 66.6% of sprout samples whereas Salmonella items in the workshops (43-45) showed that the spp. were isolated from one sprout sample (brown surfaces of cutting tools, peeling machines, centri- mung). In our study, in addition to E. coli and Sal- fuge systems, and the sorting room-air are the most monella, several Gram-negative bacteria, such as polluted parts and that secondary contamination Enterobacter, Klebsiella, and Erwinia, were found in of products can occur anywhere in the production the ready-to-eat vegetable packages, which had and contribution line. presumptive colonies on chromogenic agars; this is consistent with the results from the study of Aba- None of the heat or freezing process is used in the dias et al. (1) and Seow et al. (29). Enterobacter, Er- production of fresh ready-to-eat vegetables for re- winia spp. and other non-faecal coliforms bacteria moving microorganisms, and the common proc- have long been recognized as common organisms esses for preparing vegetables with minimal process in fresh produce, such as lettuce and fresh-cut sal- include sorting, cleaning, disinfecting, peeling, cut- ads (38). However, their presence is not considered ting, drying, packing, cold storage, and transport a public health threat but may result in spoilage of to distribution centres, depending on the products vegetables and fruits, such as Erwinia spp., which (18,46). In most cases, failure of the cold chain produce pectolytic enzymes and soften vegetable management reduces the shelf-life of the products tissues. Therefore, level of faecal organisms, such as (46). E. coli, is a better indicator of quality of fresh pro- However, disinfection with chlorine is the main duce, and this could explain why this organism has method for reducing pathogenic organisms (13) been included as a hygienic criterion in the new EU but several factors, including biofilm formation by regulation (1). bacteria, internalization of pathogens within plant In contrast to the present study, Badosa et al. (39) tissue, and the hydrophobicity of plant surfaces, reported yeast and mold counts in most of the decrease its effectiveness (47). There is a need to JHPN 396 Microbial safety of ready-to-eat vegetables Jeddi MZ et al. find alternative methods for preserving fresh-cut and growth of human pathogens on raw fruits and vegetables in order to improve the efficacy of wash- vegetables. Microbes Infect 2002;4:413-23. ing treatments. Alternatives or modified methods 5. Altekruse SF, Swerdlow DL. The changing epi- have been proposed, including irradiation (48,49), demiology of foodborne diseases. Am J Med Sci ozone (50,51), bacteriophages, antagonistic bac- 1996;311:23-9. teria (52,53), and essential oils (54,55). However, 6. WHO/FAO. Microbiological hazards in fresh leafy none has yet gained widespread acceptance by the vegetables and herbs: meeting report. Geneva: World industry. For this reason, there is a need to develop Health Organization, 2008. 138 p. (Microbiological alternative methods and, subsequently, the need to risk assessment series no. 14). develop markers to measure the efficacy of these 7. Aycicek H, Oguz U, Karci K. Determination of total alternatives. aerobic and indicator bacteria on some raw eaten Conclusions vegetables from wholesalers in Ankara, Turkey. Int J Hyg Environ Health 2006;209:197-201. Although the number of samples studied was 8. Eni AO, Oluwawemitan IA, Oranusi S. Microbial small for some items due to sampling limitations, quality of fruits and vegetables sold in Sango Ota, Ni- we believe this project provides a general overview geria. Afr J Food Sci 2010;4:291-6. of the microbiological quality of MPV and sprouts 9. Rediers H, Claes M, Peeters L, Willems KA. Evaluation commercialized in Tehran, Iran. Due to high val- of the cold chain of fresh-cut endive from farmer to ues of contamination found in MPV and sprout plate. Postharvest Biol Technol 2009;51:257-62. samples, it cannot be concluded that the fresh products analyzed have appropriate hygienic qual- 10. Burnett SL, Beuchat LR. Human pathogens associated ity. MPV are subjected to various conditions dur- with raw produce and unpasteurized juices, and diffi- ing growth, harvest, preparation, packaging, and culties in decontamination. J Ind Microbiol Biotechnol distribution that could cause increased contami- 2001;27:104-10. nation. These products are only treated by disin- 11. Harris LJ, Farber JN, Beuchat LR, Parish ME, Suslow fection, which does not assure complete removal TV, Garrett EH et al. Outbreaks associated with fresh of microorganisms. Hence, these results suggest produce: incidence, growth and survival of patho- that measures, including good agricultural prac- gens in fresh and fresh-cut produce. Comp Rev Food tices (GAP), good manufacturing practices (GMP), Sci Food Safety 2003;2:78-141. and Hazard Analysis and Critical Control Points 12. de Oliveira Silva E, do Socorro Rocha Bastos M, Wurl- (HACCP), should be implemented to reduce the itz NJ, de Jesus Barros Z, Mangan F. Minimal process- risk of microbial contamination from farm-to-fork ing. In: Rodrigues S, Fernandes FAN, editors. Advances and to assure safe products. in fruit processing technologies. Boca Raton, FL: CRC Press, 2012:217-34. (Contemporary food engineering ACKNOWLEDGEMENTS series). This research was financially supported by Tehran 13. 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Journal of Health, Population, and Nutrition – Pubmed Central
Published: Sep 1, 2014