IJERD – International Journal of Environmental and Rural Development (2020) 11-1

Research article
erd

Evaluation of Bacterial Contamination Level in Pickles Soldat Wet Market in Cambodia - Part 1- In Case of the
Samples from Kampong Cham and Phnom Penh
SHUKI MURAMATSU*
Faculty of Life and Environmental Sciences, Showa Women’s University, Tokyo, Japan
Email: s-muramatsu@swu.ac.jp

MASATAKA UCHINO
Faculty of Life Sciences, Tokyo University of Agriculture, Tokyo, JapanYURI TANIKOKA
Faculty of International Agriculture and Food Studies, Tokyo University of Agriculture, Tokyo,
Japan

SOKLY SORM
Graduate School of Agriculture, Tokyo University of Agriculture, Tokyo, JapanDAIKI OKA
Faculty of Applied Bioscience, Tokyo University of Agriculture, Tokyo, JapanYOSHIKI MURAMATSU
Faculty of Regional Environment Science, Tokyo University of Agriculture, Tokyo, JapanTORU NAKAJIMA
Faculty of Regional Environment Science, Tokyo University of Agriculture, Tokyo, Japan

MOTOE SEKIDO
Department of Food and Nutrition, Yamanashi Gakuin Junior College, Tokyo, Japan

TAKAHIKO NAKAMURA
Faculty of Regional Environment Science, Tokyo University of Agriculture, Tokyo, JapanCHIM CHAY
Faculty of Agro-Industry, Royal University of Agriculture, Phnom Penh, Cambodia

MACHITO MIHARA
Faculty of Regional Environment Science, Tokyo University of Agriculture, Tokyo, Japan
Received 15 January 2020

Accepted 23 April 2020(*Corresponding Author)

Abstract Agriculture is the main industry in Cambodia and home-made agricultural products
for local Khmer people are commonly sold at wet markets. However, food poisoning andfood-related diseases frequently occur due to these home-made products. The improper
handling of food by vendors, inadequate storing conditions, and cross-contamination risk
while on display, were observed when inspecting wet markets. Sanitary conditions in the wet
markets were poor and the food handlers seemed to treat food based on their personal
experience. In this study, we aimed to investigate the hygiene level of food products sold in
wet markets in Cambodia. In Kampong Cham, a typical small town, processed foods are
consumed in the local area and are also transported to large cities, like Phnom Penh. Pickled
vegetables, which are a popular ready-to-eat food in Cambodia, were selected and assessed
for microbial contamination. A total of 17 pickles were collected from the local market in
Kampong Cham and we measured the Brix value, salt concentration, and pH in these samples.
Adenosine triphosphate (ATP) concentration was also measured, because the amount of ATPⒸ ISERD

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in a food sample indicates the approximate microbial contamination level. The five samples
with the highest ATP values were used for a quantitative evaluation of microorganism
contamination. In addition, five other samples with relatively low ATP concentrations were
tested for comparison. An assessment of colony number and morphology indicated that nineof the samples showed initial putrefaction or putrefaction. There was one coliform-positive
sample. Similarly, three pickles purchased in Phnom Penh showed putrefaction and two
samples from these three pickles were coliform-positive. These results indicated that foodsanitary conditions are unsafe and there is a critical need for improving food safety at wet
markets in Cambodia.
Keywords food safety, contamination, wet market, pickles

INTRODUCTION
Agriculture is the main industry in Cambodia and home-made agricultural products for local Khmer
people are commonly sold at wet markets. However, food poisoning and food-related diseases occur
frequently due to these home-made products. Many consumers are not aware of the likelihood of
spoilage of the purchased product when it is stored at an unsuitable temperature for a long period(Sanlier, 2009; Odeyami et al., 2019). Therefore, food handlers and service employees have a
responsibility to provide safe food products. However, the lack of personal hygiene consciousness is
a common cause of foodborne illness (Taulo et al., 2009). There are several reports describing a low
level of knowledge regarding food hygiene among food handlers (Osaili et al., 2013; Baluka et al.,2014; Emmanuel et al., 2015). In Cambodia, the major reason for foodborne illness is that the vendors
have little knowledge of food hygiene and safety. Large-scale foodborne outbreaks are monitored byevent-based surveillance in Cambodia, but there are no formal statistics regarding individual foodpoisoning cases (Vandy et al., 2012). In addition, most foodborne diseases that occur at home areunder-diagnosed and/or under-reported (Redmond et al., 2003; Keegan et al., 2009; Vrbova et al.,2012). Therefore, the current status of hygiene conditions in Cambodia requires clarification. Here,
we aimed to evaluate the hygiene conditions of the food sales environment and food products usedby the local Khmer people. These inspections will lead to practical ways of improving food safety.
Pickles are a very common ready-to-eat food in Cambodia. There are many types of vegetables
used to make pickles. The basic procedure for making pickles is to wash the vegetables and then add
sugar, salt, and other ingredients, such as fish sauce, soy sauce, garlic, chili, and rice. Most pickles
stored in jars are placed in the sun or in a room at ambient temperature for 1 to 4 days. Some of thesepickles are fermented spontaneously by lactic acid bacteria (Chrun et al., 2017). Althoughfermentation increases the shelf-life and the nutritional value of the product, the raw materials canbe sources of microbial contamination. Therefore, these home-made fermented foods are often risky(Anal et al., 2020) and food poisoning incidents are often caused by these pickled products. Since
these pickled products are consumed daily, they can be a critical hazard if not prepared hygienically.
Investigating the quality of pickled products requires the local Khmer people to change their way of
thinking about food safety.
Kampong Cham (KPC) is a typical small town and the food products produced there areconsumed in the local area and also transported to large cities like Phnom Penh (PP). Pickled
vegetables, which are a popular ready-to-eat food in Cambodia, were selected and examined for
microbial contamination.
OBJECTIVE
The objectives of this study were: 1) to investigate the safety levels and simple chemical propertiesof pickles sold in the wet market in Cambodia, 2) to discuss the cause of the unsanitary conditionsof these samples.

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METHODOLOGY
In this study, we assessed the safety conditions of food and performed bacterial contamination
inspections of pickles sold at wet markets in Cambodia.
Market Inspection
The market inspection was conducted through observation of equipment, facilities, and displaying
and storage condition of products. The results of the evaluation of these conditions were ascertainedby asking to seller.
Food Samples Used in This Study
Popular pickled and fermented vegetables were collected from local wet markets in KPC in August,2018. The products we selected by randomly but only the products from the vendors who are able totell the detailed information such as raw materials, shelf life and the process from the production toselling. In total, 17 food samples were purchased from four vendors at three different wet markets.
In PP, three food samples were purchased at a wholesale market. The food samples used in this study
are shown in Table 1. The properties of all food samples were measured within 2 hours after
purchasing. Ten KPC samples selected for bacterial inspection were placed in a sterilized storage
bag and kept at 4°C for 7 days until examination. PP samples were kept for 6 days under the same
conditions as the KPC samples.
Measurement of Food Properties
The sugar and salt content and pH of foods affect microbial growth and these values can be indicatorsof the preservability of the food. We measured Brix sugar content (soluble solids content), salt content,
and pH of food samples using a Brix refractometer (Atago, Tokyo, Japan), a salt meter (Horiba,
Kyoto, Japan), and a pH meter (Horiba), respectively. ATP content is an approximate indication of
the microbial contamination level of food samples. The standard ATP content value required to satisfy
the sanitary conditions of food-handling rooms and equipment is 36 RLU. Therefore, samples
showing greater than 100 RLU were selected as candidates for microbial investigation. Somesamples with lower ATP content were also investigated for comparison. ATP content was measured
using a luminometer and an ATP assay kit (SystemSURE Plus; Nitta, Osaka, Japan).
Sample Preparation and Bacterial Detection by Pour Plate Method
Ten grams of food sample was mixed with 90 mL of saline containing 0.1% peptone in a sterilized
storage bag. To make a homogeneous suspension, the sample was homogenized using a stomacher.
A series of sample dilutions was used for the detection of general viable bacteria, using standard agar
medium and coliform bacteria, using desoxycholate agar medium. The solidified plates wereincubated at 35 for 48 hours.
RESULTS AND DISCUSSION
Inspection of Wet Markets in Kampong Cham
To evaluate the hygiene level of food eaten on a daily basis in Cambodia, we inspected wet markets
in KPC in August, 2018. Most food products were stored at room temperature and therefore, those
products that do not have stable preservability at room temperature were susceptible to deterioration.
In the wet markets, retailers displayed their products close together and nearly all pickled products
were stored in a plastic bin at room temperature. The celling and the lights of the market were partly
covered with dust and some unattended raw garbage was observed in the passage. Because picklesⒸ ISERD

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were displayed without a lid, flies swarmed around them. From these inspection results, the wet
market did not appear to have appropriate conditions for storing food products.
When most vendors served the pickles into a takeout bag, they did not usually use gloves, but
served by bare hand. The risk of cross-contamination was also considered to be high for various
reasons. For example, cross-contamination could occur between pickled products and other raw
products and utensils, which can harbor microbes. The accumulation of waste and the manner inwhich it was disposed and stored may also result in the transport microbes and may lead to foodproduct contamination. Although vendors decided on an approximate expiration date, unsold
products were stored at room temperature. The hygiene conditions of the wet market meant that the
food being sold was highly susceptible to microbial contamination.
From the inspection of the wet market, we concluded that the food products being sold were nothandled in a hygienic manner. Therefore, we performed an assessment of food contamination levels
in pickle products from the wet market.
Chemical Properties of Pickles from KPC and PP Markets
Popular pickle products were selected and examined for quality and safety. Seventeen pickle samples
were purchased at the local wet markets in KPC and three pickle samples were purchased from a wet
market in PP. These samples were measured for Brix value, salt concentration, pH, and ATP content
immediately after purchase. The samples included several types of pickles. The Brix values ranged
from 5.7 to 49.5 °Bx and salt concentration ranged from 1.4 to >25%. The pH values ranged from
3.6 to 5.2 (Table 1).
Table 1 Chemical properties of pickles from KPC and PP markets
RegionVendorSample No.

Product nameATP (RLU)

Brix

pH

Salt (%)

Kampong
Cham

A

a-1

Young Pickled Onion

5

33.5

3.7

8.1

a-2

Slice Fermented Cucumber

4

32.6

4.2

5.5

a-3

Fermented Cucumber

5

30.8

4.6

12

a-4
a-5

Young Pickled Cucumber
Salty-sweet Raddish

378
94

10.7
16.0

4.3
5.2

3.8
5.6

b-1

Young Pickled Onion

21

31.8

3.6

7.8

b-2

Young Pickled Cucumber

542

40.9

4.3

1.4

b-3

Salty-sweet Radish

91

25.9

5.2

5.8

b-4

Fermented Cucumber

2

43.0

4.0

13

b-5

Fermented Green Mustard

184

16.9

3.6

3.0

b-6

Fermented Ginger

4

31.4

4.0

8.3

b-7

Fermented Papaya

400

49.5

4.9

9.1

b-8

Fermented Mustard

64

5.90

3.9

-

c-1

Fermented Papaya

148

48.3

4.3

9.6

c-2

Fermented Small Mustard

212

9.80

4.2

3.2

d-1

Fermented Sprout

5

14.3

3.9

4.4

d-2

Fermented Cabbage

1

16.8

4.0

3.8

E

p-1

Fermented Cucumber

1

40.5

4.1

7.2

F

p-2

Fermented Green Mustard

1,882

5.70

4.0

>25

G

p-3

Fermented Green Mustard

201

6.60

-

>25

B

C

D

Phnom
Penh

Generally, most bacteria required a minimum water activity (aw) of 0.88-0.91, most yeasts
require a minimum aw of 0.88 and regular molds need an aw < 0.88 (Matthews, et al., 2017). TheⒸ ISERD

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theoretical amounts of salt and sugar required to achieve an aw value of 0.88 (salt) and 0.92 (sugar)
are 17.8% and 62.6%, respectively. The minimum and maximum ATP content values were 1 and
1,882 RLU, respectively, with 55% of food samples showing ATP content values greater than 36
RLU.
Microbial Contamination Level of Food Samples from KPC and PP Markets
Of the 17 food samples from the KPC market, 10 were examined for general viable bacterial counts
and for coliform bacteria (Table 2). Four samples from the KPC markets and two samples from thePP market had bacterial counts greater than 7.00 log10 colony-forming units (CFU)/g. These samples
showed initial putrefaction and they were not suitable for consumption. Moreover, after observing
the colonies on the detection plates, 12 samples were found to contain various unwanted microbes.
One sample from the KPC market and two samples from the PP markets were found to be coliformpositive. Generally, coliform bacteria are not able to grow at pH values less than 4.0 (Besser et al.,
1993; Zhao et al., 1994), but some E. coli strains are reported to grow even at pH 3.8 (Presser et al.,
1997; Zhao et al., 1993). The pH values of the coliform-positive samples were 4.1 and 4.0 for samples
p-1 and p-2, respectively. It was not clear if E. coli could proliferate under these pH conditions, but
the contamination with coliform bacteria was considered to have occurred during the preparation ofthese products. The pickle samples with lower salt concentration, such as a-4, b-2, and c-2, tended toshow higher log10 CFU/g values. However, other samples with high salt and sugar concentrations
also contained unwanted microbes. The result of Table 2 showed that 55% of the sample from the
KPC market and all samples from the PP market were not enough microbial quality to eat. Taking
into consideration our inspection results, it is assumed that some steps lead to the contamination. The
causes of contamination are presumed by raw materials, the process of food processing, storage
condition. These steps might have contained complicated factors and there may multiple routes of
the contamination.
Table 2 Microbial contamination level of food samples from KPC and PP markets

Kampong Cham

Phnom Penh

Sample
No.

log10
CFU/g

Coliform

a-1

3.36

Negative

a-4

7.77

Negative

b-2

8.00<

Negative

b-3

3.30

Negative

b-4

3.68

Negative

b-7

5.48

Positive

b-8

6.88

Negative

c-1

6.27

Negative

c-2

8.00<

Negative

d-1

7.00

Negative

p-1

4.06

Positive

p-2

7.18

Positive

p-3

7.14

Negative

CONCLUSION
In this study, we evaluated the hygiene conditions of local wet markets in KPC and investigated thesafety level and chemical properties of pickled products sold at wet markets in KPC and PP. The
pickle samples were found to be highly contaminated with unwanted microbes and these productsⒸ ISERD

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were unsuitable for consumption. This result strongly suggested that the principle cause of foodcontamination is improper food handling. In Cambodia, food handlers and vendors seem to lacksufficient knowledge of food safety and do not have the opportunity to practice safe food handling.
Food safety education is considered to be one of the challenges for the future to reduce the incidenceof food poisoning.
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