International Journal of Food Sciences and Nutrition (1998) 49, 17-26

The microbiological quality of street foods in Jakarta as compared to home-prepared foods and foods from tourist hotels

Jenny van Kampen,’ Rainer Gross,2 Werner Schultink2 and Avita Usfar’

‘Regional SEAMEO-TROPMED Center on Community Nutrition, University of Indonesia, JI Salemba Raya 6, 10430 Jakartu, Indonesia, ’Deutsche Gesellschaft f i r Technische Zusammenarbeit (GTZ) GmbH, c/o PO Box 3852, 10038 Jakarta, Indonesia

Street foods are ready-to-eat foods which are important for the diet of especially poor people in developing countries. However, street foods are often suspected of being contaminated with pathogenic bacteria. The quality of street foods was compared with similar home-prepared foods and foods obtained from tourist hotels. Samples of three types of Indonesian dishes were analyzed for indicator organisms using dry hydratable film. Additional western meals were also obtained from the hotels. Background information was obtained from the food preparers by using a questionnaire. The microbial quality of nasi goreng (fried rice) and safe ayam (grilled chicken with peanut sauce) was usually acceptable: numbers of total coliform were low and often no Escherichia coli was found. Gad0 gad0 (a dish mainly consisting of vegetables, peanut sauce and bean curd) had higher contamination levels. The gad0 gad0 obtained from street food vendors had especially high counts of total coliform and Escherichia coli with median counts of 5.5 lo6 (total coliform) and 6.0 1@ (E. coli), respectively. The serving temperature might contribute to this difference in contamination level because nasi goreng and safe ayam are served hot and gad0 gad0 is served cold. The quality of the three western foods obtained from hotels was not better than that of the Indonesian dishes served; however the quality differed among the four hotels from which samples were obtained. Even food obtained from five-star hotels was sometimes unsafe (counts per gram for APC > 10’; total colifom > I d ; E. coli > lo’). Lack of facilities and a limited knowledge of hygiene, particularly of the street food vendors, may have led to poor handling practices, such as storing cooked vegetables at ambient temperature for long periods, resulting in relatively high levels of contamination.

Introduction

In many cities of developing countries, the sale of ‘street foods’ is a flourishing business. Street foods are ‘ready-to-eat foods and beverages prepared and/or sold by vendors especially in streets and other similar public places’ (FAO, 1988). Street foods are making an increasingly important contribution to the diet of many

people in developing countries, especially those in the poorer parts of a population. Nutritional investigations carried out in India, Indonesia, Nigeria and Peru indicated that freshly cooked traditional street foods provide a considerable source of various nutrients (FAO, 1988). With more people working outside of the home, street

Correspondence to Jenny van Kampen.

0963-7486/98/010017-10 0 1998 Carfax Publishing Ltd

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18 J. van Kampen et al.

foods become the most accessible source of food intake for large parts of urban populations in developing countries mawson & Canet, 1991; FAO, 1988).

However, the raw materials used for street foods and the handling practices in preparing street foods may cause health problems (Daw- son & Canet, 1991). In particular, high con- tamination of street foods with pathogenic microorganisms may cause diarrhoea of other diseases. Therefore, in order to assure adequate quality, the microbiological aspects of street foods need more attention.

In the past decade, several Hazard Analyses Critical Control Point (HACCP) studies have been carried out, both in individual homes (Bryan et af., 1992, Michanie et af., 1988) and in street settings (e.g. Bryan et al., 1988, 1992a, 1992b; Streetfood Project, 1992). However, most of these studies gave information in absolute terms of microbiological contamina- tion, and there is little information about the relative risk, compared to foods from other locations.

Hotel foods are considered to be of better quality than street foods, because better facili- ties are available in hotels, and because hotels are dependent upon maintaining a sound reputa- tion with visitors. El-Sherbeeny et ul. (1985) compared the microbiological quality of Egyp- tian rice-dishes sold by street food vendors and in hotels. Hotel foods were not always of better quality than street foods, although storage temperatures at four- and five-star hotels were more frequently estimated as ‘safe’.

Handling practices of street food vendors and of people preparing their food at home may not differ very much. For example, holding cooked foods at ambient tempexatures for several hours is common in developing countries (Bryan et al., 1992b). Home-prepared food may also not be safe (Bryan et uf., 1992c) and the findings of Tinker (1987) seem to indicate that in general, street foods are as safe as, or safer than, foods prepared in the homes of most consumers. According to the FA0 (1988), pathogens found in street foods do not differ substantially in type from those found in foods prepared and served indoors, but probably the potential problems caused by street foods are greater in terms of the incidence and the severity.

In summary, there is little information about the relative safety of street foods as compared to

home-prepared foods and hotel foods in devel- oping countries. According to Abdussalam & Kierstein (1993) ‘no convincing evidence appears to exist that street foods are more implicated in the transmission of infection and intoxication than are foods obtained elsewhere’. Therefore, it would be necessary to compare street foods with home-prepared foods and hotel foods in order to obtain information on the relative quality of street foods.

It was the objective of this study to compare Indonesian traditional dishes prepared in street food settings, in the homes of people, and in five-star hotels. It was hypothesized that street foods are of the same quality as foods prepared by people at home. Hotel foods were expected to be of better quality. As an additional reference, western foods prepared in five-star hotels were investigated as well.

Materials and methods Foods Dishes analyzed in the study consisted of traditional Indonesian and western meals as shown in Table 1. The dishes were classified as staple food, vegetable or meat. The Indonesian dishes were represented by mi gomng (a fried rice dish), gudo gad0 (a popular traditional Indonesian dish consisting of cooked veget- ables, egg, soybean curd and peanut sauce), and sate u y m (grilled chicken with peanut sauce), respectively. The western dishes consisted of spaghetti bolognese, potato salad, and beef with a mushm/onion sauce, respectively.

Subjects Twenty-one ambulant streed food vendors (six toight for each meal) from the business area of Kuningan, South Jakarta participated in the research. The vendors were mainly young men, with a median age of 25 years. Sate ayum

Tnble 1. Surveyed food groups with the corresponding typical Indonesian and Western-style dishes

Staple fwd dish Vegetable dish Meat dish

Indonesian dish Nasi goreng Gad0 gad0 Sate ayam WesbXll dish Spaghem bolognese Potato salad Beef with sauce

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Quality of street foods in Jakarta 19

vendors all originally came from Madura (Island of Javanese coast), whereas most gad0 gad0 sellers came from the sampling area of Kuningan. Nasi goreng vendors came from Central or East Java. Food was only obtained from push carts, which looked quite similar. Nasi goreng samples were obtained in part from a nearby district, called ‘Menteng’. Customers were office workers and students; tourists were not common in this area.

Home-prepared food was obtained from the ‘Karet’ neighbourhood, situated within walking distance of Kuningan. The wife of the head of this district asked her friends to cook meals. Six women and one man with a median age of 46 prepared nasi goreng; four gad0 gad0 dishes were obtained as well. The women were mainly housewives; their husbands had jobs such as managers, civil servants and factory workers.

Executive chefs of four five-star hotels in the center of Jakarta, which employed several hundred people for food preparation, and one airport catering service were contacted. Kitchen-staff members responsible for cooking the meals were interviewed. When possible, samples were taken from the buffet. However, often the desired food item was not available in the buffet; in this case samples were obtained straight from the kitchen (a la carte). The kitchen-staff members were not informed beforehand when the sampling would take place.

Microbiological examination Samples of whole meals were taken at lunch- time between 1200 and 1400 hours with the kitchen utensils provided by‘ the vendors. For food items supposed to be eaten with the hands (sate ayam). sterile laboratory utensils were used. Samples were put in a sterile bag and cooled with the ice cubes to maintain a low temperature during transit. The samples were transported in an insulated container to the laboratory, where they were analyzed the same afternoon.

Aerobic mesophilic plate count (APC), total coliform and Escherichia coli colony counts were determined. Samples of food were CN- shed, using a disinfected mortar. In duplicate, 20g samples of foods were homogenized with saline containing 1% Tween 80 and 0.1% peptone in sterile screw-capped flasks by means of manual agitation for 3min. Based on the

expected number of bacteria, further dilutions (1 : 10) were made. Two types of Petrifilm dishes (manufactured by 3M, Medica GmbH, Borken, Germany) were used - one for the identification of E. coli and total coliform and another for AF’C. They were incubated at 35°C for 24 (coliform) or 48 (APC and E. coli) hours. Petrifilm dishes (dry rehydratable film) for the enumeration of aerobic bacteria and total coli- form and E. coli in foods have been tested and adopted as official methods by the AOAC (Curiale & Sons, 1990; Curiale et al., 1991).

Questionnaire A questionnaire was used to obtain information concerning the following topics: (1) social background; (2) ingredients; (3) facilities; (4) knowledge of hygiene; and (5 ) handling prac- tices. Observations were limited to the sur- roundings and preparation of the meal just before serving.

Analysis of data The microbiological data were analyzed using non-parametric tests. To compare meals obtained from street food vendors with meals from another source, the Mann-Whitney U-test was applied. The Kruskal Wallis test for non- parametric one-way ANOVA was used to compare the hygiene of a certain meal from the three sources. Furthermore, within the group of hotels, the Wilcoxon Matched-Pair Signed- Ranks test was applied to compare traditional food with western food and to compare methods of calculating bacterial counts. The Friedman test for two-way ANOVA was applied to ascertain a rank order of hotels. The level of significance was P < 0.05.

The information obtained from the ques- tionnaires was reported qualitatively, rather than quantitatively. Sample size and study design (taking whole meals) are not suitable to corre- late microbiological data with data obtained from the questionnaire.

Results

Microbiological quality Figures 1 to 3 show the median and the ranege of the counts of colony forming units (CFU) for the traditional dishes. No significant difference was found among nasi goreng samples obtained from the three different sources (Figure 1).

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20 J. van Kampen et al.

nasi goreng - 81 v I

APC Cdiorm E. coli

Figure 1. Median and range of the logarithm of the counts of colony-forming units (CFU) per gram of ready-toeat mi gonng obtained from diffeamt sources. < is displayed when no CFU were found at the lowest dilution used

However as shown in Figure 2, there was a significant difference among sources of gad0 gudo for all three measures of microbial contamination: APC (P = 0.006), coliform (P = 0.003) and E. coli (P = 0.04). Counts of APC of gad0 gad0 obtained from street food vendors were higher than counts from this food item obtained from people at home (P = 0.01), or from hotels (P = 0.008). No difference between home-prepared and hotel-prepared food is found. This pattern was similar for coliform (P

ado gad0

* = P< 0.05

APC coliiorm E. coli

1 Street Home Hotel I (n = 8) (n=4) (n = 4)

Figure 2. Median and range of the logarithtn of the counts of colony forming units (CFU) per gram of ready-to-eat gad0 god0 obtained from different sources. < is displayed when no CFU were found at the lowest dilution used. * means statistically difference (P < 0.05) of indicator counts of a meal obtained from a certain source. as compared to the meal obtained from other sources.

sate ayam

* = Pe0.05 2 e- -I-

" APC Cdiorm E. coli

Home Hotel I (n = 8) (n = 4) (n=4)

Figure 3. Median and range of the logarithm of the counts of colony forming units (CFU) per gram of ready-toeat sate uyam obtained from different sources. e is displayed when no CFU were found at the lowest dilution used * means statistically significant difference (P e 0.05) of indicator counts of a meal obtained from a certain source, as compared to the meal obtained from other sources.

= 0.01 and 0.003, respectively) and E. coli (P = 0.05 for both comparisons). Sure g u m was difficult to obtain from homes during lunchtime on a normal weekday: this food item is normally prepared at parties in the evening. Therefore street foods were only compared with hotel food (Figure 3). Coliform count of the meat dish from street vendors was significantly higher (P = 0.01) than that from hotels. There was no significant difference between the two sources for either E. coli or APC.

No significant difference was found between Indonesian food and the corresponding western food prepared at the hotels; counts were all in the same range. Nasi gorent was compared with spaghetti bolognese; gad0 gad0 with potato salad and sure ayam with beef with sauce. However, if coliform counts each of these six dishes were examined, a rank order of hotels could be identified (P = 0.05). Also, the same rank order was maintained if all counts of APC, coliform and E. coli were combined (P = 0.002). When included, the catering service ranked second among the hotels (P = 0.04 and O.OOO9, respectively).

Ingredients Ingredients differed substantially between dishes obtained from different sources, espe- cially the ingredients of naso goreng and gad0 gudo. In street foods, for example, meat from

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Quulity of street foods in Jakarta 21

chicken or goat was added to MSO goreng, whereas at homes shrimp was more common. Hotels sometimes used canned sauce for their products, which was not used by street food vendors or by people at home. Peanut sauce and bean sprouts were standard ingredients of gad0 gado, but street-vended gad0 gad0 varied from day tooday, according to what was available. Leafy vegetables were not commonly used in street foods, as opposed to gad0 gad0 obtained from other sources. Other vegetables like car- rots were typically used by street food vendors. Raw vegetables like cucumber, and potato were also typical for street-vended gad0 gado.

Facilities Samples were all taken in the rainy season. Temperatures in the street and in the homes were around 30°C at lunchtime, with little variation. In the air-conditioned hotel kitchens and restaurants, temperatures were around 25°C. Public garbage collection was available in the sampling areas. In Kuningan, close to vending points, and in Karet, ditches with duty stagnant water were observed. Plates, pans and the immediate surroundings of the push carts of the street vendors usually looked tidy and clean.

In the street and in the homes, open fires were used to heat the nasi goreng and chicken meat. Fuels like petroleum and coal were commonly used in the street, whereas people at home made use of petroleum; gas or electricity was often available as well. All hotels used microwave ovens in addition to gas and other electrical appliances for cooking. Hot food items in the buffet were heated continuously in a tray by means of open f ie or electricity.

None of the sellers of gad0 gad0 in the street had a heating or cooling source. Also, ice was also not available to street food vendors selling other meals. In homes, a refrigerator with a freezing compartment was generally available. Besides cooling and freezing rooms, which were found in every hotel, an advanced method of cooling such as blast chilling was found in one hotel. A cooling device for gad0 gad0 or potato salad in the hotel buffet was not always present. Sometimes small portions were replaced every half hour (buffet 'a la minute'), or the food was cooled with ice.

Unboiled water from the local drinking water company, boiled or unboiled water from a

pump, or well water was used for food prepara- tion both by street food vendors and 6y people at home. Water used by hotels was obtained from a pump and made drinkable by ultratiltration.

Street food vendors washed dishes and uten- sils in one or two buckets containing cold water, using soap and a wiping cloth. People at home also used cold water and soap, but water taps were available in the kitchen. In hotels, water taps were often found in many parts of the kitchen and utensils were washed with soap and hot water.

Knowledge and perception of hygiene Table 2 shows the knowledge and perception of hygiene and the handling practices of the 22 food handlers. When street food vendors (n = 20) were asked what might make food unsafe, most of them (60%) could not answer. Six out of seven people who prepared their food at home came up with a response. For most vendors and people at home the ingredients are blamed for unsafe food. In the hotels four cooks were interviewed who were responsible for the food purchase, food storage, and meal prepara- tion. Their answers were more detailed when they described causal factors for unsafe meals such as extensive storage time, high frequency of touching food, inadequate cleaning of kitchen.

Most of the vendors in the street (80%) or the people at home (5 out of 7) had never had any formal or informal training regarding food handling or cooking. Three vendors (15%) had learned cooking from friends; one vendor visited a bazaar organized by the university. lbo people at home had taken a course organized by a women's organization. In con- trast, courses including topics on hygiene were obligatory for cooks in hotels.

Handling practices Causes of improper handling practices could be related to either lack of facilities or lack of knowledge about habits concerning hygiene. Hand-washing before food preparation, for example, was not common in the street, and touching food with bare hands was common. Half of the vendors responded that they washed iheir hands after handling food in an available bucket of water, since running water is not available. People at home and hotel cooks stated

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22 J. van Kampen et al.

Table 2. Knowledge and peroepti~~ of hygiene and handling practices of interviewed food handlers (n = 22) ~

Street (n = 21: 20 push cam;

Five-star hotel (n = 4)

1 jixed stall) Home (n = 7)

n % n n

Knowledge and perception of hygiene

Reason for unsafety? (open question, prestructud answers) Microorganism Dirty water Improper hygienic conditions Improper food handling Non-nutritious food All food is healthy

Missing value

Training received Formal training University Women’s organization Friends Without

Missing value

Handling practices (some of the questions about,) Garbage disposed

Public collection Taken home

Missing value

Utensils cleaning

Don’t know

Washing machine with hot water By hand, with cold water and soap By hand, witb cold water only Never cleaned

3 4 1

15 1 20 1 - 5 0 0 1 60 - 5 1

- -

12 1

1

- 0 5 0 2 l5 1 80 4

- - 1

3 16 1

-

18 2 1

90 10

6

1

-

0 86 10 4

- 18 2 1

When hands are washed? (open question, prestructured answers)

After handling Before cookingihandling Both after and before handling foodhoking After handling money After handling money and before cooking After handling garbage Before getting to work During washing the dishes After activities Often Missing value

10 4 2 1 1

1 1

-

50 20 10 5 5 0 5 5 0 0

1 2 1

- 1

- 1 1 -

1

that they washed their hands very often: before, during and after cooking.

Street food vendors bought vegetables and meat early in the morning (about 5.00a.m.). They cooked the perishable ingredients at home

or at the selling place, and stored the pre- prepared food at ambient temperature in the pushcarts until the final preparation when the meal was ordered. Bu lunchtime storage time could have been as long as 10 hours, the

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Quality of street foods in Jakarta 23

average time being 7 hours. People at home .usually went to the market at about 9.00a.m. and cooked the meal just before lunchtime. Gad0 gad0 was prepared a few hours before serving and stored at ambient temperature until lunchtime. In hotels, vegetables were delivered every morning; meat every day or every 2 or 3 days. After washing and slicing in special preparation kitchens, the raw items were stored cool until the setup of the buffet. Samples were taken just before the opening of the buffet at lunchtime.

Left-over food was not common in any of the three sampling areas. When there were left- overs, they were usually thrown away or sometimes eaten by the vendors or cooks themselves. In one hotel plain rice was fried again and used as the basis for preparing nasi goreng. In hotels, sauces were usually stored in the refrigerator for several days.

A wood mortar was used by street food vendors to prepare the peanut sauce for gado gado. Metal utensils were used for preparation of other street foods and for all foods at homes and at hotels. Street food vendors mostly used clean looking waxy paper in their push carts to store vegetables, or banana leaves to store raw meat.

Discussion The rapidity of the method of using Petrifilm dishes for microbiological examinations has evident advantages, but also some disadvan- tages. An important limitation is the very small amount of growth medium used in a Petrifilm dish. With respect to APC the amount of culture medium and its surface area restricts discrim- ination and definition of colonies tobout 150 per plate; with respect to total coliforms the con- conetent formation of gas bubbles limits the colonies per plate to a maximum of 100; and with regard to E. coli the presence of the blue precipitate makes for a maximum of only about 50 discernible colonies. The lower dilutions often showed considerably fewer than the expected number of colonies ( A X : P = 0.05, coliform: P = 0.009, E. coli: P = 0.03). Probably this was caused by growth disturbance on a crowded plate with only a small amount of medium. It seemed better to take intooaccount dishes with only around 20 colonies. The average of two appropriate dilutions was taken

to calculate the number of colony forming units per gram of food, the lower limit being diminished to ten colonies per Petrifilm dish.

Although this expensive - but easy and rapid - method had the above mentioned disadvan- tage, the value of the results should not be denied. The method may be imprecise, but can only result in an underestimation of the results. Furthermore, in independent studies, the dry- film plaing method has been shown to be useful for the accurate determination of bacterial counts for a broad variety of food types (Curiale & Sons, 1990; Curiale et al., 1991).

There were no differences between mi goreng obtained from the different sources. This may be related to the thorough heating of street foods just before serving: temperatures were always in the safe range, which is above 60°C. Nasi goreng with the highest counts of APC was obtained from the buffet of one of the five-star hotels. These results are similar to those of a study among street food vendors performed in Bogor (city in West Java, Indonesia): nasi rums, a mixed rice dish, in general appeared to be of acceptable microbiological quality. The main cause of contamination seemed to be improper handling of prepared food, rather than inadequate preparation procedures of the vari- ous components (Hartog, 1992).

Microbiological counts for sate ayam from street food vendors seem to be somewhat higher than when obtained from hotels. The difference, however, is only statistically significant for coliform bacteria. High counts of coliform in street foods were observed in meat that seemed to be still raw inside. Sate ayam obtained from street food vendors may be relatively safe if the meat is well roasted. Gad0 gado, however, is a product of concern,

especially when obtained from street food vendors: the lowest count for coliform was 8.4 X 16. Home-prepared gad0 gad0 shows counts which are not that high, but even gad0 gad0 obtained from hotels have median counts of coliform above 1202CFU/gram. Gad0 gad0 free from E. coli (<lOCFu/gram) was obtained only once from every respective source. The recovery of E. coli in foods implies that other organisms of fecal origin may be present, including pathogens (ICMSF, 1978). E. coli may be a common cause of food poisoning and is also thought to be associated with traveller’s diarrhoea (Hobbs & Roberts, 1992).

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24 J. van Kampen et 41.

In a study performed among gad0 gad0 sellers in Bogor (Indonesia), the vegetables were identified as cause for the high counts (Streetfood Project, 1992). Results of separate microbiological examinations of ingredients obtained in Kuningan, however, indicate that Zonrong (sticky rice) and tahu (fried bean curd) also contribute to the high counts, especially those of coliform and E. coli. The vendor bought these food items already prepared at the market in the morning. Peanut sauce which he made himself and which was stored overnight at ambient temperature was free of E. coli (<lOCFU/gram). These results indicate that multiple causes may be involved. Ingredients could have been contaminated at the market. Contamination could have occurred via the hands of the vendor or the knife used to slice the ingredients (crosscontamination) or via wooden cutting boards. These boards are often heavily soiled and are used for both raw and cooked foods (Bryan er al., 199%).

When searching for possible causes of the high counts of gad0 gad0 obtained from street food vendors, it is valuable to compare informa- tion obtained from people at home with that from the vendors. Although counts of home-prepared gad0 gad0 are lower, some circumstances concerning hygiene and facilities, like the water source for food preparation were similar. Some handling practices like the storage of food were the same; while freshly prepared food was highly appreciated by all subjects. Storage of food at ambient temperature before serving was com- monplace in the street, but also with people at home, though a refrigerator was available at the latter place. There were no differences between vendors and home cooks that could account for the differences between the two levels of contamination.

Bryan (1995) reviewed data from many different countries and concluded that hazards from street foods do not differ greatly from those of foods cooked in homes or in food- service establishments. However, variation depends on the kind of microorganisms that are likely to reach the foods, the preparation and holding practices, and the knowledge of the person who prepares the foods. In Jakarta significant differences between street vendors and other food preparers are the availability of running water and the knowledge of hygiene. The latter may be related to age: street food

vendors comparised a younger population. Washing hands might become a more common habit in the street if water taps were made available. This may be an important improve- ment, as most fecal organisms are readily washed from the skin by soap and water (Hobbs & Roberts, 1992). Another main difference between street foods and home-prepared foods lies in the longer storage time at ambient temperature of the former. As pH and moisture content are high, the shelf-life of vegetables at ambient temperature is limited. Pathogenic or harmful organisms have plenty of opportunity to grow during 7 hours at 30°C. From reports of investigations of foodborne disease outbreaks and surveillance data, it is well known that generally the most significant factor is leaving foods at ambient temperature for many hours. Large numbers of coliform bacteria (usually >16) and counts for APC ranging from lo6 to lo9 were isolated from all foods after handling and then holding for several hours (Bryan, 1995). These levels of contamination are com- parable with the levels found in Jakarta. Fur- thermore, the common use of raw vegetables like cucumber in street foods introduces an extra risk factor. Hotels sometimes use special detergents to wash raw vegetables.

No difference was found between Indonesian food and western food served in hotels. Some of the samples of potato salad for example, appeared to be unsafe, with counts being in the same range as counts for gad0 gad0 obtained from hotels. Although ingredients of westem and traditional dishes differ, the raw materials will be treated in the same way in the hotel kitchen. Facilities, knowledge and perception of hygiene and handling practices of the cooks also will be the same; which may explain the similar micro- biological quality of comparable food items.

Only six food items were obtained from every hotel. However, despite this small number dishes with very high and dishes with low counts were found. The catering service for airplanes has strict hygiene rules (IFCA, 1994) and the meals showed low counts. However, counts of food items from the hotel which has the most advanced equipment were somewhat lower than that of the catering service. The highest overall counts were obtained from the hotel with the oldest kitchen. The quality of facilities and the rules applied may be of importance for general hygiene and food hygiene.

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Quality of street fooh in Jakarta 25

Usually research on street foods is limited to food that is expected to have the largest microbial load. An important conclusion which can be drawn from the research project in Kuningan, Jakarta is that hot food items obtained from street food vendors may be comparatively safe if the meat is well cooked during preparation.

A dish like gado gado, however, which is not heated just before serving, is of worse quality than the same dish prepared at homes of people or prepared at a five-star hotel. Storing the cooked ingredients for a long time at ambient temperature might be an important cause for this lower quality, although contamination from the hands of the vendor may also contribute. Samples of food from hotels occasionally have high microbial counts as well. Traditional Indoensian food do not differ from western food in this respect. Even within the group of five- star hotels, differences in food hygiene exist.

It could be interesting to take samples from small Indonesian restaurants. In Egypt, rice dishes obtained from small hotels were of even worse quality than rice dishes obtained from street food vendors, probably due to longer storage times while there is a general lack of facilities (El-Sherbeeny et al., 1985).

Furthermore, it is important to study in depth the biological contamination of gudo gad0 in

Jakarta, using the format of an HACCP-study. This study should provide the basic knowledge which would be needed to develop proper intervention modules to improve the safety of gado gado.

Another subject for further study is the acceptability of possible changes in gad0 gad0 by street food vendors that could potentially lower the microbial load. Adding lemon juice to lower the pH is advised for food items l i e es cendol, a beverage with coconut milk and ice (Streetfood Project, 1992); it would be worth- while to check the possibility of adding diluted lemon juice to cooked vegetables. Furthermore, the effect of washing raw vegetables with special detergents on microbial load could be checked. If there was positive effect then the feasibility of the use of this product should be investigated.

Acknowledgements-The authors wish to thank Ir. Harsi D. Kusumaningnun (lkpartment of Microbiology, Agricul- tural University, Bogor) Drs Aidilfit Chatim, MSc (Depart- ment of Microbiology, University of Indonesia, Jakarta), and Leonas Chatim for their help during the study. Furthermore, the authors thank Prof. Dr J.G.A.J. Hautvast and Dr A.P. den Hattog (Department of Human Nutrition, Agricultural University Wageningen), Ir. J.C. de Wit (Department of Food Microbiology, Agricultural University Wageningen) and Ir. B.J. Hartog (TNO, Zeist) in the Netherlands for their support. Finally, the authors express their gratitude to Dr D. Finley for critically reviewing the manuscript.

References Abdussalam M & Kserstein FK (1993): Safety of street

foods. World Health Forum 14, 191-194. Bryan FL (1995): Hazard analyses of street foods and

considerations for food safety. Duiry, Food und Environ- ment Sanitation 15, 64-69.

Bryan FL, Michanie SC, Alvarez P & Paniagua A (1988): Critical control points of street-vended foods in the Dominican Republic. J. Food Protect. 51, 373-383.

Bryan FL, Teufel P, Riaz S, Roohi S, Qadar F & Malik Z-U- R (1992a): Hazards and critical control points of street- vending operations in a mountain resort town in Pakistan. J. Food Prof. 55, 701-707.

Bruan FL, Teufel P, Riaz S , Roohi S, Qadar F & Malik Z-U- R (1992b): Hazards and critical control points of street- vended Chat, a regionally popular food in Pakistan. J . Food Prof. 55, 708-713.

Bryan FL, Teufel P, Riaz S , Roohi S, Qadar F & M a l i Z-U- R (1992~): Hazards and critical control points of food preparation and storage in homes in a village and a town in Pakistan. J. Food Prot. 55,714-721.

Curiale MS & Sons T (1990): Dry rehydratable film for enumeration of total aerobic bacteria in foods: collabora- tive study. J. Assoc. Off Anal. Chem 73,242-248.

Curiale MS, Sons T & McIver D (1991): Dry rehydratable film for enumeration of total coliforms and Escherichiu coli in foods: collaborative study. Assoc. O$ A d . Chem.

Dawson RI & Canet (1991): International activities in street foods. Food Control 2, 135-139.

El-Sherbeeny MR, Saddik MF, Aly HES & Bryan FL (1985): Microbiological profile and storage temperatures of Egyptian rice dishes. J. Food Prot. 48, 39-43.

FA0 (1988): Stmer food: Report of an FA0 expert consulrution, Jogjakarta, Indonesia, 5-9 December 1988. FA0 Regional Office for Europe, Paper 46. Rome: Food and Nutrition Division, FAO.

Hartog A (1992): Application of the HACCP concept to improve the safety of street foods. Food Lab. News 8,

Hobbs BC & Roberts D (1 992): Food Poisoning and Food

74, 635-648.

23-39.

Int J

Foo

d Sc

i Nut

r D

ownl

oade

d fr

om in

form

ahea

lthca

re.c

om b

y T

ufts

Uni

vers

ity o

n 11

/14/

14Fo

r pe

rson

al u

se o

nly.

26 J. van Kampen et al.

Hygiene, 5th edn. London: Edward Arnold. ICMSF (1978): M i c ~ ~ ~ r g a n i s m r in Food. 1. Their Sig-

nificance and Methods of Enumcratiom, 2nd edn. Inter- national Commission of Mianbiological Specifications of Foods of the Inteanational Association of Microbio- logical Societies. Toronto: University of Toronto Ress.

IFCA (1994): Basic Food Safety Control - Based on HACCF! Geneva, IFCA Hygiene Committee.

Michanie S. Bryan IT., Mendoza F e r n W z N, Moscoso

V i M, Taboada PD, Navarros 0, Bravo Alonso A & Santillau ML (1988): Hazard analyses of foods prepared by inhabitants along the Pew& Amazon river. J. Food

Streetfood Project (1992): Food safety Studies - Volume 1: Selected P d u c t s . Working Report No. 8. Bogor, Indo- nesia: "NO-IPB-W.

T i e r I (1987): The case for legalizing street foods. Ceres

Pmt. 51,293-302.

20.26-31.

Int J

Foo

d Sc

i Nut

r D

ownl

oade

d fr

om in

form

ahea

lthca

re.c

om b

y T

ufts

Uni

vers

ity o

n 11

/14/

14Fo

r pe

rson

al u

se o

nly.