A total of 112 burger patties (35 beef burger patties, 39 chicken burger patties and 38 fish burger patties) which are commercially available at retail level were investigated for the presence and number of Listeria monocytogenes. These samples were analyzed using MPN-PCR method and conventional culturing methods. L. monocytogenes was detected in 33.3% of chicken burger patties, 22.9% of beef patties, and 10.5% of fish patty samples. From all contaminated raw burger patties, the estimated count of L. monocytogenes was ranged from 3 to 75 MPN/g. The results suggest that burger act as a potential source of listeriosis if the contaminated burger patty is consumed without adequate cooking. The risk associated with consumption of these samples was found to be high particularly for processed food at retail level in Malaysia. Therefore, food manufacturers play an important role in monitoring the manufacturing process and conduct a periodical surveillance on microbiological quality assessment on the processing plants. Besides, there is a need to increase awareness of consumers and food handlers to practice proper cooking of the burger patties before the point of consumption, to reduce the risk of listeria infection.
This study was undertaken to characterize the antibiotic resistance and randomly amplified polymorphic DNA (RAPD) profiles of Vibrio parahaemolyticus isolates from raw vegetable samples. A total of 46 isolates of V. parahaemolyticus recovered from raw vegetables samples and were confirmed by PCR were analyzed in this study. Most of the isolates were resistant to nalidixic acid (93.48%) and were the least resistant towards imipinem (4.35%). The MAR index results also demonstrated high individual and multiple resistances to antibiotics among the isolates. From the RAPD analysis, the size for RAPD fragments generated ranged from 250 bp to 1,500 bp, with most of the strains contained three major gene fragments of 350, 1,000 and 1,350 bp. The RAPD profiles revealed a high level of DNA sequence diversity within the isolates. Antibiotic resistance and RAPD proved to be effective tools in characterizing and differentiating the V. parahaemolyticus strains.
The purpose of this study was to investigate the biosafety of Vibrio parahaemolyticus in raw salad vegetables at wet market and supermarket in Malaysia. A combination of Most Probable Number - Polymerase Chain Reaction (MPN-PCR) method was applied to detect the presence of V. parahaemolyticus and to enumerate their density in the food samples. The study analyzed 276 samples of common vegetables eaten raw in Malaysia (Wild cosmos = 8; Japanese parsley = 21; Cabbage = 30; Lettuce = 16; Indian pennywort = 17; Carrot = 31; Sweet potato = 29; Tomato = 38; Cucumber = 28; Four winged bean = 26; Long bean = 32). The samples were purchased from two supermarkets (A and B) and two wet markets (C and D). The occurrence of V. parahaemolyticus detected was 20.65%, with higher frequency of V. parahaemolyticus in vegetables obtained from wet markets (Wet market C = 27.27%Wet Market D = 32.05%) compared to supermarkets (Supermarket A = 1.64%; Supermarket B = 16.67%). V. parahaemolyticus was most prevalent in Indian pennywort (41.18%). The density of V. parahaemolyticus in all the samples ranged from <3 up to >2400 MPN/g, mostly <3 MPN/g concentration. Raw vegetables from wet markets contained higher levels of V. parahaemolyticus compared to supermarkets. V. parahaemolyticus were present in raw vegetables although in low numbers. The results suggest that raw vegetables act as a transmission route for V. parahaemolyticus. This study will be the first biosafety assessment of V. parahaemolyticus in raw vegetables in Malaysia.
Salmonellosis is one of the major food-borne diseases in many countries. This study was carried out to determine the occurrence of Salmonella spp., Salmonella Enteritidis, and Salmonella Typhimurium in raw chicken meat from wet markets and hypermarkets in Selangor, as well as to determine the antibiotic susceptibility profile of S. Enteritidis and S. Typhimurium. The most probable number (MPN) in combination with multiplex polymerase chain reaction (mPCR) method was used to quantify the Salmonella spp., S. Enteritidis, and S. Typhimurium in the samples. The occurrence of Salmonella spp., S. Enteritidis, and S. Typhimurium in 120 chicken meat samples were 20.80%, 6.70%, and 2.50%, respectively with estimated quantity varying from <3 to 15 MPN/g. The antibiogram testing revealed differential multi-drug resistance among S. Enteritidis and S. Typhimurium isolates. All the isolates were resistance to erythromycin, penicillin, and vancomycin whereas sensitivity was recorded for Amoxicillin/Clavulanic acid, Gentamicin, Tetracycline, and Trimethoprim. Our findings demonstrated that the retail chicken meat could be a source of multiple antimicrobial-resistance Salmonella and may constitute a public health concern in Malaysia.
The present study aimed to provide an insight of C. jejuni ATCC 33560 phenotype profiles (carbon sources and sensitivity to osmolytes and pH) using Phenotypic MicroArray (PM) system in response to optimal and suboptimal temperature. C. jejuni ATCC 33560 showed utilization carbon sources from amino acids and carboxylates but not from sugars. C. jejuni ATCC 33560 is sensitive to NaCl at 2% and above but showed survival in a wide range of food preservatives (sodium lactate, sodium phosphate, sodium benzoate, ammonium sulphate and sodium nitrate). When incubated at suboptimal temperature, no phenotype loss was observed in carbon source plates. Phenotype loss of C. jejuni ATCC 33560 was observed in sodium chloride (1%), sodium sulphate (2-3%), sodium formate (1%), sodium lactate (7-12%), sodium phosphate pH7 (100mM and 200mM), ammonium sulphate pH8 (50mM), sodium nitrate (60mM, 80mM and 100mM), sodium nitrite (10mM), and growth in pH5. The phenotypic profile from present study will provide a better insight related to survival of C. jejuni ATCC 33560.
This goal of this study was to investigate the presence of Vibrio cholerae in street food,
namely satar and otak-otak, using Loop-Mediated Isothermal Amplification (LAMP),
multiplex Polymerase Chain Reaction (mPCR) and conventional plating on Thiosulphate
Citrate Bile-Salt Sucrose (TCBS) agar methods. A total of 78 satar and 35 otak-otak were
purchased from different districts of Terengganu (Besut, Setiu, Kuala Terengganu and
Kemaman). V. cholerae was found in satar with LAMP (10.3%), mPCR (10.3%) and
plating (0%). No V. cholerae was found in otak-otak using the three methods. This might
be due to V. cholerae able to survive in satar after grilling due to its thickness which may
contribute to undercooking. This study concluded that low presence of V. cholerae in satar
and otak-otak can be detected by molecular methods but not the conventional plating
method. LAMP assay is a useful tool for rapid detection of pathogens in food due to its
simplicity, highly sensitive and visual interpretation capability. Though the prevalence of
V. cholerae was low in the samples, proper handling of this food will help in reducing the
risk of acquiring infection from V. cholerae in contaminated samples.
We quantified Campylobacter jejuni transferred from naturally contaminated raw chicken fillets and skins to similar cooked chicken parts via standard rubberwood (RW) and polyethylene cutting boards (PE).
Numerous prevalence studies and outbreaks of Vibrio parahaemolyticus infection have been extensively reported in shellfish and crustaceans. Information on the quantitative detection of V. parahaemolyticus in finfish species is limited. In this study, short mackerels (Rastrelliger brachysoma) obtained from different retail marketplaces were monitored with the presence of total and pathogenic strains of V. parahaemolyticus. Out of 130 short mackerel samples, 116 (89.2%) were detected with the presence of total V. parahaemolyticus and microbial loads of total V. parahaemolyticus ranging from <3 to >10(5) MPN/g. Prevalence of total V. parahaemolyticus was found highest in wet markets (95.2%) followed by minimarkets (89.1%) and hypermarkets (83.3%). Pathogenic V. parahaemolyticus strains (tdh+ and/or trh+) were detected in 16.2% (21 of 130) of short mackerel samples. The density of tdh+ V. parahaemolyticus strains were examined ranging from 3.6 to >10(5) MPN/g and microbial loads of V. parahaemolyticus strains positive for both tdh and trh were found ranging from 300 to 740 MPN/g. On the other hand, antibiotic susceptibility profiles of V. parahaemolyticus strains isolated from short mackerels were determined through disc diffusion method in this study. Assessment of antimicrobial susceptibility profile of V. parahaemolyticus revealed majority of the isolates were highly susceptible to ampicillin sulbactam, meropenem, ceftazidime, and imipenem, but resistant to penicillin G and ampicillin. Two isolates (2.99%) exhibited the highest multiple antibiotic resistance (MAR) index value of 0.41 which shown resistance to 7 antibiotics. Results of the present study demonstrated that the occurrence of pathogenic V. parahaemolyticus strains in short mackerels and multidrug resistance of V. parahaemolyticus isolates could be a potential public health concerns to the consumer. Furthermore, prevalence data attained from the current study can be further used to develop a microbial risk assessment model to estimate health risks associated with the consumption of short mackerels contaminated with pathogenic V. parahaemolyticus.
Bacillus cereus (B. cereus) isolates are toxigenic and can cause food poisoning. Cooked rice is
a potentially hazardous food, especially in tropical countries. The aim of this study was to determine the prevalence of B. cereus and B. thuringiensis in raw and cooked rice marketed in Selangor, Malaysia. In this research combination of Most Probable Number - Polymerase Chain Reaction (MPN-PCR) was used to detect gyrB gene in B. cereus and B. thuringiensis. Five local varieties of raw rice samples were negative for B. thuringiensis but all (100%) were positive for B. cereus. A total of 115 cooked rice samples (nasi lemak, nasi briyani, nasi ayam and nasi putih) were studied for the presence of B. cereus and B. thuringiensis. Nasi ayam was found to have the highest prevalence (100%) of B. cereus compared to nasi putih (76.2%) and nasi lemak (70.4%). Nasi briyani had the lowest prevalence (50%) of B. cereus. The frequencies of B. thuringiensis were found to be 10, 30 and 35.2 % in nasi putih and nasi ayam, nasi briyani and nasi lemak, respectively. The range of B. cereus and B. thuringiensis in the samples was from < 3 to 1100 MPN/g in different samples. Maximum number of B. cereus was observed in nasi lemak, nasi briyani and nasi putih ( > 1100 MPN/g) while nasi ayam showed less contamination (460 MPN/g) with B. cereus which was significantly different (P < 0.05 ) from others. The number of B. thuringiensis in nasi lemak, nasi briyani, nasi putih and nasi ayam were found to be >1100, 93, 9.2 and 3.6 MPN/g, respectively.
Vibrio parahaemolyticus is a halophilic Gram-negative bacterium that is considered among
gastrointestinal pathogens. Thirty isolates were tested for their susceptibility using 14 different
antibiotics. One V. parahaemolyticus isolate was resistant to 10 antibiotics (cefotaxime,
ceftazidime, tetracycline, amikacin, ciprofloxacin, levofloxacin, ofloxacin, ampicillin,
amoxicillin-calv-acid, and cefepime). The V. parahaemolyticus isolates were resistant to
ampicillin (90%), amoxicillin–clavulanic acid (63.3%), cefotaxime (60%), ceftazidime (46.7%),
cefepime (50%), tetracycline (36.6%), and amikacin (26.7%). However, the isolates were highly
susceptible to imipenem (100%), and piperacillin and gentamicin (96.7%). Approximately
55% of the isolates showed a multiple antibiotic resistance (MAR) index of >0.2, thereby
indicating the high risk of sources where these isolates originated. The occurrence of MAR
asserted the importance of determining drug susceptibility and monitoring the antimicrobial
resistance profile to improve and ensure food safety and public health.
Salmonellosis outbreaks involving typhoid fever and human gastroenteritis are important diseases in tropical countries where hygienic conditions are often not maintained. A rapid and sensitive method to detect Salmonella spp., Salmonella Typhi and Salmonella Typhimurium is needed to improve control and surveillance of typhoid fever and Salmonella gastroenteritis. Our objective was the concurrent detection and differentiation of these food-borne pathogens using a multiplex PCR. We therefore designed and optimized a multiplex PCR using three specific PCR primer pairs for the simultaneous detection of these pathogens. The concentration of each of the primer pairs, magnesium chloride concentration, and primer annealing temperature were optimized before verification of the specificity of the primer pairs. The target genes produced amplicons at 429 bp, 300 bp and 620 bp which were shown to be 100% specific to each target bacterium, Salmonella spp., Salmonella Typhi and Salmonella Typhimurium, respectively.
Foodborne pathogens have become a constant threat to the consumer and food industry.
Reduce efficacy of antibiotics with emergence of resistant bacteria has limited the opportunities
for controlling pathogenic bacteria in food commodities and treating foodborne infections.
Bacteriophages can be a promising alternative for alleviate the risk of transmitting pathogenic
bacteria via food commodities. Therefore, this research was conducted to find distribution of
bacteriophages in diverse niches in order to identify suitable sources for isolating bacteriophages
to use controlling foodborne pathogens. Firstly bacterial strains were screened for lysogenic and
selected suitable host bacterial strains were used for isolating and determining bacteriophage titer
in fresh raw food and environmental samples. Eighteen different lytic bacteriophages effective
against Campylobacter, S. aureus, L. monocytogenes and E. coli were isolated from this study.
Bacteriophages titer was determined within range of 102
to 1010 PFU/mL and bacteriophages
were most frequently isolated from chicken (60%) samples. The isolated bacteriophages could
be potential candidates for controlling foodborne diseases.
Campylobacter is globally recognized as a major cause of foodborne infection in humans, whilst the development of antimicrobial resistance and the possibility of repelling therapy increase the threat to public health. Poultry is the most frequent source of Campylobacter infection in humans, and southeast Asia is a global leader in poultry production, consumption, and exports. Though three of the world's top 20 most populated countries are located in southeast Asia, the true burden of Campylobacter infection in the region has not been fully elucidated. Based on published data, Campylobacter has been reported in humans, animals, and food commodities in the region. To our knowledge, this study is the first to review the status of human Campylobacter infection in southeast Asia and to discuss future perspectives. Gaining insight into the true burden of the infection and prevalence levels of Campylobacter spp. in the southeast Asian region is essential to ensuring global and regional food safety through facilitating improvements in surveillance systems, food safety regulations, and mitigation strategies.
Campylobacter is a major foodborne pathogen frequently associated with human bacterial gastroenteritis in the world. This study was conducted to determine the prevalence and antibiotic resistance of Campylobacter spp. in the beef food system in Malaysia. A total of 340 samples consisting of cattle feces (n = 100), beef (n = 120) from wet markets and beef (n = 120) from hypermarkets were analyzed for Campylobacter spp. The overall prevalence of Campylobacter was 17.4%, consisting of 33% in cattle fecal samples, 14.2% in raw beef from wet market and 7.5% in raw beef from the hypermarket. The multiplex-polymerase chain reaction (PCR) identified 55% of the strains as C. jejuni, 26% as C. coli, and 19% as other Campylobacter spp. A high percentage of Campylobacter spp. were resistant to tetracycline (76.9%) and ampicillin (69.2%), whilst low resistance was exhibited to chloramphenicol (7.6%). The MAR Index of Campylobacter isolates from this study ranged from 0.09 to 0.73. The present study indicates the potential public health risk associated with the beef food system, hence stringent surveillance, regulatory measures, and appropriate interventions are required to minimize Campylobacter contamination and prudent antibiotic usage that can ensure consumer safety.
Escherichia coli O157:H7 is a major food-borne pathogen that has resulted in numerous
outbreaks around the world. Widespread distribution of the organism in various ecological
niches impedes the control measures. This study aimed to detect and quantify E. coli O157:H7
in beef sold in wet markets and hypermarkets in Malaysia and to determine the risk of E. coli
O157:H7 infection linked to consumption of beef. The rfbO157 and flicH7 primers targeted on
somatic antigen (O157) and flagellar antigen (H7) respectively of E. coli O157:H7 was used for
the MPN-PCR method. A total of 99 beef samples were collected from local wet markets and
hypermarkets. The highest E. coli O157:H7 contamination rate was observed in beef samples
collected from wet markets (89.50%), whereas the contamination rate in hyper market A and B
were compratively low (35.35 and 20% respectively). However, the microbial load was highest
in the beef samples from hypermarket A (1100 MPN/g) while E. coli O157:H7 bacterial load
in beef samples from hypermarket B and wet market ranged from 3 to 93 MPN/g and 3 to 240
MPN/g, respectively. Using the Quantitative Microbial Risk Assessment (QMRA) approach
the risk was estimated incorporating the findings of the prevalence study and predictions
based on home storage, cooking and consumption patterns. Three different exposure pathways
were investigated to estimate the risk associated with contaminated beef and Monte Carlo
simulation was used to determine the level of uncertainty. The developed model predicated that
consumption of contaminated beef can be accountable for 1.83E+06 E. coli O157:H7 cases per
year in Malaysia. The reliability of the model, data gaps and further research needs, is discussed.
Through continuous improvement Quantitative Microbial Risk Assessment provides valuable
insight into controlling and prevention strategies.
To date, cholera has cycle the world seven times through the seven pandemic cycles that has
affected tens of millions of people. The objective of this study was to determine the presence
and density as well as the antibiotic resistance profile of Vibrio cholerae isolated from catfish
(Pangasius hypohthalamus). From the combination of the Most Probable Number-Polymerase
Chain Reaction-plating on TCBS agar methods, V. cholerae was detected in 32 samples and
V. cholerae O139 was detected in 7 samples, with a density ranging between
Little is known on the biosafety level of Vibrio spp. in freshwater fish in Malaysia. The purpose of this study was to investigate the prevalence and concentration of Vibrio spp. and V. parahaemolyticus in
freshwater fish using the Most Probable Number-Polymerase Chain Reaction (MPN-PCR) method. The study was conducted on 150 samples from two types of freshwater fish commonly sold at hypermarkets, i.e. Pangasius hypophthalmus (catfish) and Oreochromis sp. (red tilapia). Sampling was done on the flesh, intestinal tract and gills of each fish. The prevalence of Vibrio spp. and V. parahaemolyticus was found to be 98.67% and 24% respectively with higher percentages detected in samples from the gills followed by the intestinal tract and flesh. Vibrio spp. was detected in almost all red tilapia and catfish samples. V. parahaemolyticus was detected in 25% of the catfish samples compared to 22.6% of red tilapia fish. The density of Vibrio spp. and V. parahaemolyticus in the samples ranged from 0 to 1.1x107 MPN/g. Although the maximum value was 1.1x107 MPN/g, most samples had microbial loads ranging from 0 to >104 MPN/g. The outcome on the biosafety assessment of Vibrio spp. and V. parahaemolyticus in freshwater fish indicates another potential source of food safety issues to consumers.
Several Norovirus cases due to consumption of green onions have been reported during recent years but reports on red onions are not found. Onions are one of the major tastes in Malaysian food which are sometimes consuming raw especially the green onion. Viral contamination in onions can occur due to planting condition and not properly prepared food. This situation can pose the human health risk. A method was developed to detect the Norovirus that might present on different type of onions. In this study, 60 samples were collected from local market. Elution by Tryptose Phosphate Glycine broth and concentration steps using negatively charge filter were applied to enhance the detection of virus in food due to low copies of virus on food surface. The viral RNA was extracted using Qiagen Rneasy Mini kit before further detection using One-step RT-PCR. The total incidence of Norovirus in green onion and red onion was 13.33% (4/30) and 3.33 % (1/30) respectively. This is the first report of the detection of Norovirus in red and green onions in Malaysia. Based on the results, it is concluded that this method is reliable to detect Norovirus on onions and vegetables surface and hence can be applied in the laboratories for routine or food borne outbreak investigation.
Vibrio parahaemolyticus is recognized as a frequent causal agent of human gastroenteritis due to the consumption of raw, undercooked or mishandled seafood in many Asian countries. The number of V. parahaemolyticus cases reported is on the rise, and this becomes a concern to the Asian countries as seafood is favoured by Asians. This study aimed to detect and quantify V. parahaemolyticus in raw oysters and to determine the risk associated with the consumption of raw oysters. A total of 30 oyster samples were collected and analysed in this study. MPN-PCR and MPN-Plating methods were employed and carried out concurrently to determine the prevalence of V. parahaemolyticus in raw oysters. The results showed that the prevalence of total V. parahaemolyticus in oysters was 50.00% (15/30) where the MPN/g range was < 3 – > 11000 MPN/g for MPN-PCR method, and 40.00% (12/30) where the MPN/g range was < 3 – 4300 MPN/g for MPN-Plating method. MPN-PCR method was able to estimate the level of virulence (tdh+ and trh+) V. parahaemolyticus in the raw oysters where 10.00% (3/30) of samples were identified to be in a range of 3 – 30 MPN/g. A microbial risk assessment was conducted based on the enumeration data obtained from MPN-PCR method using @risk. The probability of illness annually was 1.76 X 10-6 with a prediction of 31 cases to occur with respect to the exposed Malaysian population, while the rate per 100,000 people was estimated to be at 0.104. In addition, the antibiogram of V. parahaemolyticus was determined using Kirby Bauer Disk Diffusion Test and the results indicated that the isolates were highly resistant towards Bacitracin (100.00%), Vancomycin (100.00%) and were least resistant to Chloramphenicol (8.70%). The MAR index of the isolates ranged from 0.17 to 0.50. In accordance with the results from this study, the consumption of raw oysters is a risk factor for V. parahaemolyticus infection and proactive actions should be taken to reduce the risk of the pathogen in order to improve public health.
Cross contamination is one of the most important contributing factors in foodborne illness
originating in household environments. The objective of this research was to determine the
transfer between naturally contaminated chicken liver and leg to cutting board, hand glove,
knife and cucumber, during slicing. The microorganism tested was Campylobacter jejuni and
the results showed that the pathogen transferred to all utensils, at different transfer rate, despite
the low level of the naturally contaminating pathogen. With unknown concentration bacteria in
the naturally contaminated samples, a proportion of the utensils were still contaminated with C.
jejuni and not surprisingly, when the sample were contaminated with higher concentrations of
the pathogen, a higher proportion of the utensils had detectable C. jejuni cells present, though
in many cases cross contamination seems to be a random event. Transfer of the naturally
contaminating C. jejuni from the chicken liver and leg to the utensils were