Presence of Norovirus in food can cause viral gasteroenteritis. Recently, lots of reports relating to Norovirus in food have been published. Special attention must be paid to the raw foods as they are not subjected to further heat treatment. In this study, pegaga, kesum, tauge and ulam raja (popular salad vegetables in Malaysia) were investigated for Norovirus. A total of 32 samples from each type of salad vegetables were purchased from local market and analyzed using One-step RT-PCR (Reverse Transcriptase-Polymerase Chain Reaction) for both genogroups namely Norovirus Genogroup I and Genogroup II. Results showed that tauge had the highest contamination with Norovirus Genogroup I (15.6%) comparing to pegaga (9.4%), kesum (12.5%)
and ulam raja (0%). Samples were free from Norovirus Genogroup II. The study showed that raw vegetables are high-risk foods and can be contaminated with Norovirus.
This study aimed to investigate the prevalence and antibiogram of Vibrio parahaemolyticus in processed bivalve molluscs in Kuala Terengganu. A total of 80 seafood samples, namely mussels (n=20), carpet clams (n=20), cockles (n=20) and scallops (n=20), were subjected to PCR and conventional plating method for the detection of V. parahaemolyticus. V. parahaemolyticus was found in green mussels (55%), carpet clam (80%), cockles (40%) and scallops (55%). Fifty-five V. parahaemolyticus isolates were subjected to 9 types antibiotic sensitivity test using discs diffusion method. All isolates were susceptible to Tetracycline and Gentamycin. Isolates showed high resistance towards Vancomycin (52.73%), Penicillin (45.45%) and Amplicillin (32.73%). Resistance towards Amikacin, Ciprofloxacin and Norfloxacin were found to be 1.82%. It can be concluded that local bivalve molluscs were contaminated with V. parahaemolyticus and isolates showed resistance towards certain antibiotics. Therefore, consumption of raw or semi-cooked bivalve molluscs is not advisable.
Three restriction enzymes were used in Polymerase Chain Reaction-Restriction Fragment Length Polymorphism (PCR-RFLP) using the mitochondrial cytochrome b region to establish a differential diagnosis which detect and discriminate between three meat species: pork, cow and chicken. DNA was extracted from samples containing meat of a single animal such as raw pork (Sus scrofa domesticus), chicken (Gallus gallus) and cow (Bos taurus) as well as mixed samples of two species of animals in different ratios. The amplified 359 base pairs (bp) portion of the mitochondrial cyt b gene from pure or mixed samples in different ratios was cut using three different restriction enzymes resulting in species specific restriction fragment length polymorphism (RFLP). This technique proved to be extremely reliable in detecting the presence of low levels of target DNA obtained from a 0.25 mg component in a particular mixed meat sample. This revealed the cyt b region as highly conserved and consequently a good molecular marker for diagnostic studies. Thus, this technique can be applied to food authentication for the identification of different species of animals in food products.
The prevalence of Campylobacter spp. in retailed sushi were examined using the techniques of polymerase chain reaction (PCR) in combination with most probable number (MPN) to quantify the bacteria in 150 samples obtained from three supermarkets. The average prevalence of Campylobacter spp. in retailed sushi was 26.6% with 32%, 16% and 32% from supermarket I, II and III, respectively. Campylobacter jejuni was found to be the predominant species in retailed sushi with 82.49% of all Campylobacter spp. positive samples. Campylobacter coli was not detected in all samples. The maximum MPN number of Campylobacter spp. in retailed sushi purchased from supermarket I, II and III ranged from 3.6-11.0 MPN/g, 9.4->1100 MPN/g and 27-1100 MPN/g, respectively. The isolation of C. jejuni from a variety of ready-to-eat retail sushi may indicate that these products can act as possible vehicles for the dissemination of food-borne campylobacteriosis.
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.
As the society begin to realize the importance of combating antimicrobial resistance, going
back to silver might be the solution. Silver has been known for its potential antimicrobial
activity since ancient times and, the development of nanoparticles has increased its potential
into becoming an antimicrobial agent that can be applied in broad-spectrum. Antimicrobial
resistance has spread into an irrepressible manner which requires drastic action plan as a number
of pathogenic bacteria began to acquire resistance genes. Methicillin Resistant Staphylococcus
aureus (MRSA) is one of the earliest reported resistant clones which is the center of this study.
This study focused on the dissemination and evolution of MRSA on its resistance towards
antibiotics. Disc Diffusion Test was employed to create the antibiograms of MRSA isolates. All
isolates showed resistance towards amoxicillin, ampicillin, cefazolin, oxacillin and penicillin.
In contrast, all isolates were susceptible towards erythromycin. The findings also discovered
isolates that were vancomycin-resistant (66.7%) and vancomycin-intermediate (33.3%). As the
efficacy of antibiotic treatment is at a question, we also investigated on the antimicrobial activity
of colloidal silver in the hope as an alternative treatment. Shiga Toxin producing Escherichia
coli (STEC) and MRSA (ATCC 33591) was tested using modified Quantitative suspension
test for the evaluation of bactericidal activity for chemical disinfectants and antiseptics based
on BS EN 1276:2009. The outcome of this study indicated that the colloidal silver is working
effectively against STEC and MRSA (ATCC 33591), showing killing percentages well above
99.0% at 4 minutes and 8 minutes of contact. Vancomycin-resistant S. aureus (VRSA) and
Vancomycin-intermediate S. aureus (VISA) were also tested and the results indicated that
VISA had higher killing percentages at 4 minutes (99.83%) and 8 minutes (99.85%) compared
to VRSA at 4 minutes (96.72%) and 8 minutes (98.35%). This opens a solution to the rising
problem of antimicrobial resistance.
Vibrio parahaemolyticus is well known to be abundantly distributed in marine, coastal and
estuarine environments. Since 1951, V. parahaemolyticus had been the source of numerous
outbreaks related to contaminated or mishandled seafood. However, V. parahaemolyticus
had been detected on other types of food. This issue has prompted this study to investigate
on the prevalence of V. parahaemolyticus in various food samples and determine the risk
associated with it. The results of the MPN-plating technique of the study indicated that V.
parahaemolyticus was detected in seafood (33.3%, 95% Confidence Interval [CI] 31.9 – 34.8 ,
94 – 290 MPN/g) and vegetables (10.0%, 95% CI 9.7 – 10.3 , 9.2 – 23 MPN/g) while negative
V. parahaemolyticus was detected in fruits (0.0%, 95% CI 0 – 1,
Antibiotic susceptibility and genetic diversity of E. coli isolated from cultured catfish and their surrounding environment were determined. The levels of resistance of the E. coli isolates towards six different antibiotics tested differed considerably. Though the isolates displayed resistance towards some of the antibiotics tested, none of the isolates showed resistant towards norfloxacin, sulphametoxazole/trimethoprim and chloramphenicol. RAPD-PCR analysis using single primer and primers combination clustered the E. coli isolates into 3 and 5 groups, respectively. The results of this study suggest that the E. coli isolates from the catfish and their surrounding environment derived from a mixture of sensitive and resistant strains with diverse genetic contents. The use of the RAPD analysis is sufficiently discriminatory for the typing of the E. coli isolates.
The aim of this work was to investigate the antioxidant and antimicrobial of Phyllanthus amarus, Phyllanthus niruri and Phyllanthus urinaria. P. niruri was found to possess the highest antioxidant activity, the activity decreased in the order P. niruri > P. amarus > P. urinaria for water extract. However, the activity decreased in the order P. niruri > P. urinaria > P. amarus for methanol extract. The result correlation between the antioxidant activity and total phenolic content revealed a positive correlation of 0.954 < r 2 < 1.000 for both water and methanol extract. Methanol extract showed higher total phenolic content and antioxidant activity as compared with water extract. Lowest Minimum Inhibitory Concentration (MIC) value for water extract against the selected microorganism was >2.5 mg/mL meanwhile, for methanol extract was 2.5 mg/mL and >0.625 mg/mL were the value for water and methanol extract. Methanol extract showed better inhibition potential than water extract
Ninety one leaf samples of Josapine pineapple cultivar (Kelantan, n=8; Pahang, n=20; Perak, n=11; Sabah, n=15; Johor, n=37) showing symptoms of heart rot disease were collected to determine the incidence of Erwinia chrysanthemi. Sixteen strains of E. chrysanthemi were isolated from 13 leaf samples from Pahang (n=4), Sabah (n=2) and Johor (n=7). All of the E. chrysanthemi strains displayed resistance to bacitracin with two strains showing resistance to sulfamethoxazole. None of the E. chrysanthemi strains were resistant toward ampicillin, carbenicillin, cephalothin, ceftriaxone, cefuroxime, gentamicin, kanamycin, nalidixic acid, penicillin G, streptomycin and tetracycline. All of the E. chrysanthemi strains were plasmidless. The dendrogram generated from the ERIC-PCR fingerprinting showed that the E. chrysanthemi strains formed 4 clusters and 7 single isolates at 80% similarity level. The restriction fragment length polymorphism (RFLP) analysis for 16 strains of E. chrysanthemi with HinfI and HaeIII endonuclease, 2 and 4 restriction profiles were obtained, respectively. The combinations of the four techniques were able to differentiate the 16 E. chrysanthemi strains into 14 genome types, suggesting a wide diversity of strains examined. ERICPCR fingerprinting method is found to be more discriminating and useful for the determination of the E. chrysanthemi strains relatedness.
Biochemical analysis was carried out for pH profiles, freshness in terms of K-values, amino acids profiles, total volatile bases (TVB), total volatile acids (TVA) and biogenic amines for fresh and preserved Macrobrachium rosenbergii. Results showed that pH profiles of Macrobrachium rosenbergii explain the inability of this parameter to be used to evaluate the quality of Macrobrachium rosenbergii. Thus changes in pH profiles of Macrobrachium rosenbergii should be combined with indicators such as total volatile acids and total volatile bases. Total volatile acids of the shrimps increased steadily in small amounts throughout the storage period. A rapid increase in TVB at 100C was detected due to the increase in total aerobic bacteria at elevated temperatures. The microbial activities caused the decrease in the amino acids arginine, lysine and histidine which correlated well with the increase in the corresponding biogenic amines such as putrescine, cadaverine and histamine respectively. Preservatives used in this study controlled the production of these biogenic amines without significantly altering the pH of preserved shrimp.
Salmonella has been reported to be presence both in raw and processed foods worldwide. In this study, the prevalence, quantification and antibiotic susceptibility of Salmonella isolated from raw vegetables or locally known as ulam such as asiatic pennywort (Centella asiatica (L) Urb), water dropwort (Oenanthe javanica (Blume) DC), long bean (Vigna sinensis EndL), and winged bean (Psophocarpus tetragonolobus (L) DC) obtained from retail markets in Selangor, Malaysia were carried out. From 96 samples tested, the overall prevalence of Salmonella spp. was 97.9%, Salmonella Enteritidis was 54.2% and Salmonella Typhimurium was 82.3% respectively. Samples were contaminated with Salmonella ranging from < 3 to 2400 MPN/g. Salmonella Enteritidis and Salmonella Typhimurium isolates obtained from the raw vegetables (ulam) were found to exhibit high resistance against ampicillin (100%), erythromycin (100%), amoxicillin/clavunic acid (81.3%), cephalothin (75%), streptomycin (50%) and ciprofloxacin (50%). All Salmonella isolates showed multi drug resistant (MDR) profile with each isolate being resistant to 3 or more antibiotics. The multiple antibiotic resistance (MAR) index of Salmonella isolates ranged from 0.27 to 0.55 for Salmonella Enteritidis and 0.27 to 0.82 for Salmonella Typhimurium. The presence of Salmonella on raw vegetables (ulam) and high antibiotic resistance isolates indicated that raw vegetables could be contaminated and thus imposes possible health risk to local consumers.
Listeria monocytogenes (L. monocytogenes) is an important foodborne pathogen which can cause foodborne listeriosis with high mortality rates especially in susceptible population groups such as pregnant women, elderly and immunocompromised individuals. The biosafety level of L. monocytogenes in chicken offal has becomes a great concern as chicken offal is a cheap source of protein and it is often served as side dishes in South East Asian countries. In Malaysia, the consumption of chicken offal has almost doubled from 5 g per capita per day in the early 1980s to 9 g per capita per day in 2009. In this study, risk assessment was conducted to estimate the risk of acquiring listeriosis from consumption of chicken offal in Malaysia. A microbial survey on the prevalence and concentration of L. monocytogenes in chicken offal were carried out in Selangor, Malaysia over a one-year period (November 2010 to October 2011). It was assumed that there were no seasonal changes in the prevalence and consumption pattern all year round. Assuming that 5.6 million people in Selangor, Malaysia consume a single serving (125 g) of chicken offal per week, it is estimated that in a year there could be 0.61 cases and 1.98 × 10-4 cases of listeriosis per 100,000 population of pregnant woman and immunocompromised individual, respectively. However, the potential for getting listeriosis among the healthy population was very low, only 1.39 × 10-8 cases per 100,000 population. This study demonstrated risk assessment model not only used as a tool to estimate the risk of acquiring illness but it can influence public health surveillance and providing data in setting appropriate level of protection.
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.
Street food is popular in Asia due to its availability, low price and good taste. The safety of
street food has been always questionable due to its poor handling which probably leads to
microbial contamination. The objective of this study was to determine the surviving quantities
of V. parahaemolyticus under various conditions in street-vended food, namely satar and otakotak
after anticipated cross-contamination to support policy and regulatory documents. The
satar and otak-otak were prepared from minced and unminced fish flesh, respectively, together
with other ingredients. Each satar and otak-otak were prepared with 0, 0.5, 1.5 and 3% of
sodium chloride (NaCl), respectively. V. parahaemolyticus inoculum at approximately 8.66 log
CFU/ml were inoculated into the samples and incubated for up to 6 h. Samples were taken at 0,
1, 3 and 6 h for enumeration of V. parahaemolyticus using spread plate method on Thiosulphate
Citrate Bile Salts Sucrose (TCBS) agar. For control samples, V. parahaemolyticus was not
immediately inactivated in distilled water even though significant better survivability was
observed in Phosphate Buffer Saline (PBS). The numbers of V. parahaemolyticus was found
to decrease by varying amounts based on the salt content and duration of holding. However,
significant amounts survived to indicate potential risk.
Ultra high temperature (UHT) treated milk products and formula milk are known to be
frequently contaminated with Bacillus cereus. Presence of B. cereus in these milk products is
of particular concern considering the majority of consumers are infants and children. Possible
sources of contamination are contaminated raw milk, cross-contamination during processing,
under-processing and mishandling of milk products. This study was conducted to detect the
presence of B. cereus in both formula milk (n=12) and UHT milk (n=20) sold in selected retail
markets. The approach consisted of enumerating by MPN/g followed by PCR assay aimed
at detecting gyrB gene in B. cereus, that encode for the subunit B protein of DNA gyrase
(topoisomerase type II). Contamination level of B. cereus in both types of samples examined
ranged from < 3 to > 1100 MPN/g. The contamination level of B. cereus was found to be
highest in full cream UHT milk (> 1100 MPN/g) and formula milk (> 1100 MPN/g). The PCR
analysis showed that 41.7% (5/12) formula milk and 30% (6/20) UHT milk samples were
detected with B. cereus, respectively. This is the first report of such study demonstrating the
presence of B. cereus in formula milk from Malaysia. Therefore, constant surveillance of these
milk products would reduce the potential risk of B. cereus-linked outbreaks.
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.
Nowadays, the incidence rate of foodborne disease has increased and become one of the global burdens affecting all individual ages in South East Asia region. Foodborne disease is responsible for mortality and morbidity worldwide thus affecting socio-economic and quality of life. Major causes of foodborne hazards diseases include diarrheal and invasive infectious disease agent, helminthes and chemicals. However, in developing countries, data and record is insufficient with poor surveillance systems leading to incomplete information on the real burden of foodborne disease. The introduction of Actor Network Theory (ANT) as tools for assessing and analyzing the food safety issues has drawn attention from various researcher as it is proven to be able to point out and identify the human and non human actors which is directly and contingently involved. The interaction between the actors such as a worker in an organization, student in school, and peoples in public provide information that can be used to minimize the risk of foodborne disease. The ultimate use of ANT is it helps the researcher to draw a framework of the source of contamination, agent responsible, factors involved, and idea to control the spread.
Listeriosis and salmonellosis are the major foodborne illnesses worldwide. Over the last decade,
increasing reports about the antibiotic resistance of Listeria monocytogenes and Salmonella from diverse sources have prompted public health concerns, especially in developing countries with over reliance or misuse of antibiotic drugs in the treatment of humans and animals. In this study, antibiotic susceptibility profiles of 58 L. monocytogenes and 12 Salmonella Enteritidis strains from vegetable farms and retail markets in Malaysia were testedby the standard disk diffusion method. Listeria monocytogenes isolates were found to exhibit 100% resistance to penicillin G. Also, high resistance patterns were observed for meropenem (70.7%) and rifampicin (41.4%). The multiple antibiotic resistance (MAR) index of L. monocytogenes isolates ranged from 0.11 to 0.56. Besides, the antibiogram results revealed that multidrugresistant (MDR) S. Enteritidis were detected and all the S. Enteritidis isolates demonstrated resistance to at least four antibiotics. Ampicillin, amoxicillin, and trimethoprim failed to inhibit all the S. Enteritidis strains. Salmonella Enteritidis isolates also displayed high resistance to nalidixic acid (75.0%), trimethoprim-sulfamethoxazole (75.0%), and chloramphenicol (66.7%). Findings in this study indicated that vegetables could be potential sources of multidrug resistance of L. monocytogenes and S. Enteritidis, which can be a serious issue and a major concern for public health. Thus, there is a great need for surveillance programs in Malaysia to continuously monitor the antibiotic resistance profiles of important pathogens.
Salmonellosis is an important public health problem and causes large economic losses in the poultry industry. The emergence of molecular technology has opened various possibilities for constructing tailor-made proteins, particularly protein E from bacteriophage PhiX174 for the
production of bacterial ghosts (BGs) applied in vaccines purposes. In the present study, the plamdaPRcI-Elysis plasmid carrying the PhiX174 lysis gene E and thermo-sensitive lamda PR-cl857 regulatory system was constructed. Two Salmonella Enteritidis (SE-2 and SE- 4) and one Salmonella Typhimurium (ST-4) isolates were able to uptake the lysis plasmid via electrotransformation. Generation of ghosts was enhanced by increasing the incubation temperature up to 42˚C. Cell viability of SE-2, SE-4 and ST-4 decreased ranging in log 2.7 to log 4.1 cycles after lysis induction. Moreover, SE-2 and SE-4 exhibited the earliest reduction of CFU after 3 h of incubation. Our results may provide a promising avenue for the development of Salmonella BGs vaccines.