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Yuet Ying Loo,1 Buong Woei Chieng,2 Mitsuaki Nishibuchi,3 Son Radu11Centre of Excellent for Food Safety Research, Faculty of Food Science and Technology, Universiti Putra Malaysia, Selangor, Malaysia; 2Department of Chemistry, Faculty of Science, Universiti Putra Malaysia, Selangor, Malaysia; 3Center for South East Asian Studies, Kyoto University, Kyoto, JapanAbstract: The development of the biological synthesis of nanoparticles using microorganisms or plant extracts plays an important role in the field of nanotechnology as it is environmentally friendly and does not involve any harmful chemicals. In this study, the synthesis of silver nanoparticles using the leaves extract of Chinese tea from Camellia sinensis is reported. The synthesized nanoparticles were characterized using UV-vis spectroscopy, X-ray diffraction (XRD), transmission electron microscopy (TEM), and Fourier transform infrared (FTIR) spectroscopy. The XRD analysis shows that the synthesized silver nanoparticles are of face-centered cubic structure. Well-dispersed silver nanoparticles with an approximate size of 4 nm were observed in the TEM image. The application of the green synthesized nanoparticles can be used in many fields such as cosmetics, foods, and medicine.Keywords: silver, nanoparticles, green synthesis, leaf extract, transmission electron microscopy, nanotechnology

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. [ABSTRACT FROM AUTHOR]

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, of loxacin, 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. [ABSTRACT FROM AUTHOR]

Vibrio parahaemolyticus is a main foodborne disease in seafood and generally seafood is easily deteriorates in quality of color and flavor. In this study, clove (Syzygium aromaticum) extract shows potent antibacterial activity against growth of antibiotics resistant Vibrio parahaemolyticus on seafood samples (cockles and shrimps). Vibrio parahaemolyticus was artificial contaminates on the samples with 106 CFU/ml. The samples were treated with different concentration of cloves extract with 10 mg/ml which are 0.5%, 5% and 10% concentration from methanol food grade extraction in 0 hr, 5 min, 10 min, 15 min, 30 min, 60 min and 120 min. Tab water and deionized water were selected as a negative control. As a result, the amount of 10 % cloves managed to mitigates the number of V. parahaemolyticus on seafood samples in 5 minutes and 15 min on both samples. Therefore, our results signify the fact that cloves can be apply as natural sanitizer which could meet consumer demands for safe and traditionally consumed either raw without any undesirable effect when applied in the seafood system industries. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

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 x 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 x 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 approriate level of protection. [ABSTRACT FROM AUTHOR]

Escherichia coli and Escherichia coli O157 were identified from "selom" (Oenanthe stolonifera), "pegaga" (Centella asiatica), beef, chicken, lamb, buffalo, "ulam Raja" (Cosmos caudatus) and "tenggek burung" (Euodia redlevi). The bacteria were recovered using chromagenic agar. Isolated Escherichia coli and Escherichia coli 0157 were further characterized by plasmid profiling and enterobacterial repetitive intergenic consensus-polymerase chain reaction (ERIC-PCR). The virulence genes of the isolates (VT1, VT2, LT, ST, eaeA, inV) that produces pathogenic Escherichia coli and 16S rRNA gene were screened by a multiplex PCR assay. The plasmid profiling analysis showed that out of 176 isolates, only 103 isolates contained plasmids. ERIC-PCR analysis generated amplified products in the range of ~150 bp to > 1000 bp categorizing isolates into a total of 52 different profiles. Multiplex PCR showed that 20 (32.3%) of the isolates carried eaeA gene, 6 (9.7%) isolates possessed inV genes, only 1 (1.6%) have VT2 genes and 1 (1.6%) as well carried VT1 genes, 2 (3.2%) of the isolates harboured LT genes, and only 1 (1.6%) isolate possessed ST genes. There were no correlation between plasmid, ERIC-PCR and virulence genes profiles. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

Pathogenic Vibrio parahaemolyticus is one of the leading causes of bacterial gastroenteritis in many countries. Among the strains examined, 36 RAPD-types were found when amplified with primers OPA8 and OPA10. The analysis shows the majority of V. parahaemolyticus isolates originated from seafood were branched into four major clusters at 18.2%, 20.7% 34% and 3.4% similarity levels. This suggests that there is potential for a single strain to be distributed widely within a population and there also potential for multiple contaminating strains of different clonal lineages to be present within the same population. Optimum temperature (37ºC) was the highest and stable formation of biofilm. The total percentage of biofilm formation at 37ºC was 33.33% for each of weak, moderate and strong biofilm producers. Room temperature produces 61.1% of weak biofilm producer, while 13. 89% for moderate biofilm producers and produce 25% of strong biofilm. While a total of 91.67% weak biofilm producers at 4ºC and 8:33% for room temperature and no growth of strong biofilm. Upon analysis, strong biofilm was tracked from the largest group at 37°C and room temperature which produce 27.27% of strong biofilm producer respectively. Interestingly, they are derived from cockles. [ABSTRACT FROM AUTHOR]

Foodborne diseases are mainly caused by bacterial contamination which can lead to severe diarrhea. This study aimed to detect the presence of Shiga toxin-Producing Escherichia coli O157, Escherichia coli non-O157 and virulence gene in raw vegetables. The samples were purchased from wet market and hypermarket in Selangor. The detections were carried out by using the combination methods of Most Probable Number-Polymerase Chain Reaction (MPNPCR). A total of 37(18.5%) samples were found to be contaminated by STEC. Out of these 37 isolates, four (10.8%) of the isolates were E. coli O157 while 33(89.2%) were E. coli non-O157. However, there was no E. coli O157:H7 detected in all the samples. The occurrence of Shiga toxin-Producing E. coli in edible raw vegetables samples suggests the importance of this pathogen in vegetables. Therefore, more studies are required to remove this pathogen from vegetables. [ABSTRACT FROM AUTHOR]

Listeria monocytogenes (L. monocytogenes) is a gram positive food-borne pathogen that is able to form biofilm on food factory surfaces. Formation of biofilm makes the bacteria much more resistance to environmental stresses such as disinfectant. The extracellular polymeric matrix (biofilm structure) which is mostly comprised of sticky extracellular polysaccharides (EPS) and proteins can protect bacteria in a harsh condition. The efficiency of four disinfectants on removing L. monocytogenes biofilm was investigated. Five concentration levels (100, 50, 25, 12.5, and 6.25%) of disinfectants were tested. In the microtitre assay, the optical density at 595 nm CV-OD595 value, was used to measure the amount of remained biofilm after 24 h. Results showed that disinfectants did not have significant effect on removing L. monocytogenes biofilm. Formation of L. monocytogenes biofilm significantly decreased the efficiency of disinfectants. Biofilm produced by strain number 9 showed higher resistance to disinfectant. Low concentrations (<50%) of disinfectants did not show significant effect on removing L. monocytogenes biofilm. [ABSTRACT FROM AUTHOR]