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.
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.
Vibrio parahaemolyticus is a gram negative bacterium and causes gastrointestinal illness in humans. In this study, twenty five out of fifty cockle samples from Padang, Indonesia produced purple colonies when they were grown on selective medium, CHROMagarTM Vibrio. Specific–PCR for toxR gene detection gave positive results in which a band with 368 base pairs size appeared on the gel for all the isolates that confirmed the presence of V. parahaemolyticus. In the virulence properties test, all the isolates showed negative results for tdh and trh genes detection. The results indicate that the isolates under this study do not contain virulence properties that correlate to the ability of infection and diseases, which means that they are nonpathogenic.
The mode of action and activities of guava leaf extracts against various food pathogens were studied. The killing kinetics, viability and cell leakage of Kocuria rhizophila, Salmonella typhimurium, Listeria monocytogenes and Escherichia coli O157:H7, measured after exposure to guava methanolic extracts (GME) revealed a significantly higher (p≤0.05) release of bacterial nucleic acids, K+ ions and protein than that of untreated microbes, indicating disruption of the bacterial membrane. GME caused a significantly higher (p≤0.05) release of RNA in gramnegatives compared to gram-positives. GME caused a relatively small but significant release of pyrines and pyrimidines in all organisms investigated. GME probably disrupted the integrity of the Gram-negative microorganism lipopolysaccharide (LPS) layer. Unlike all the other microorganisms tested, E. coli O157:H7, demonstrated the lowest protein leakage, the highest K+ leakage, the highest pyrines and pyrimidines leakage within the first 10 min of extract exposure, but the lowest after 30 minutes, which may indicate their good homeostasis ability or adaptability. Understanding the mode of action of this flavonoid rich guava leaf extract, would help develop it as an alternative biodegradable and safe, antimicrobial for food and medicine, and as a by-product of the guava industry.
This study aims to determine the combined effects of hydrolysis time, temperature, pH and ratio of enzyme to substrate on the degree of hydrolysis (DH) of silver catfish frame using Response Surface Methodology. The proximate compositions of silver catfish frame and silver catfish hydrolysate powder were determined as well. The effects of independent factors were described using a three-level factors Face Centered Central Composite design. The suggested hydrolysis conditions for obtaining the optimum DH using Alcalase® were – temperature of 55oC, hydrolysis time of 163 min, pH of substrate at 9.45 and an enzyme concentration of 2.0%. The generated model showed a quadratic fit with experimental data. Proximate analyses revealed that silver catfish frame contained 25.02% protein, 68.21% fat and 7.08% ash. While silver catfish frame hydrolysate powder contained 65.05% protein, 32.92% fat and 0.86% ash. The protein recovery in silver catfish frame hydrolysate was as high as 71.6%.
Most investigations on heavy metals content in fish were either conducted on single markets, ports, seaside markets or direct sampling from natural habitat, and there were very few studies done on fish samples from both wet markets and supermarkets. This paper presents the assessment outcome of Cd and Pb levels in commercial fish sold between wet markets and supermarkets in Klang Valley, Malaysia. In this study, the organs of four commercial fish species (Rastrellinger kanagurta, Epinephelus sexfasciatus, Lates calcarifer, and Decapterus maruadsi) sampled from different markets within the sampling area were assessed using dry ashing-acid digestion method and Flame AAS. Results obtained concluded that Cd and Pb in fishes sampled from supermarkets are generally higher compared to wet markets, while both metals content in the edible organs fall well within the permissible limits for human consumption when compared to the Fourteenth Schedule of the Malaysian Food Regulations 1985.
FTIR spectroscopy in combination with multivariate calibrations, i.e. partial least square (PLS) and principle component regression (PCR) was developed for quantitative analysis of cod liver oil (CLO) in binary mixture with corn oil (CO). The spectra of CLO, CO and their blends with certain concentrations were scanned using horizontal attenuated total reflectance (HATR) accessory at mid infrared (MIR) region of 4,000 – 650 cm-1. The optimal spectral treatments selected for calibration models were based on its ability to provide the highest values of coefficient of determination (R2) and the lowest values of root mean error of calibration (RMSEC). PLS was slightly well suited for quantitative analysis of CLO compared to PCR. FTIR spectroscopy in combination with multivariate calibration offers rapid, no excessive chemical reagent, and easy in operational to be applied for determination of CLO in binary mixture with other oils.
Palm pressed fiber (PPF) is a by-product from oil extraction of oil palm fruits. It has unique characteristics resulting from the combination of palm mesocarp fiber, kernel shell and crushed kernel. The present study on different extraction methods for PPF indicated that conventional hexane cold extraction would be the more preferable method compared to soxhlet and reflux method due to the yield recovered (4.35%) and diacylglycerol (19.93% ± 0.07) obtained. Acylglycerol composition using cold extraction gave high Diaclyglycerol and Triacylglycerol (67.04% ± 0.05) with reasonable amount of Monoaclyglycerol / Free Fatty Acid (13.02% ± 0.02). Lauric acid which was not present in crude palm oil were found to be significant in PPF (5.89 to 9.09%), thus making this oil suitable for application in the food industry in products such as shortening and margarine.
Proximate content and fatty acid composition of germinated and non-germinated legumes (kidney, mung, soy bean and peanut) and rice varieties (red, black, Barrio, brown and milled) were evaluated. In germinated samples, moisture content increased significantly while carbohydrate, protein and fat were decreased significantly. Total dietary fibre was increased in germinated samples except germinated kidney and mung bean. Germination also increased saturated fatty acids (SFA) in legumes, black, red and brown rice. Monounsaturated fatty acids (MUFA) decreased in all samples except germinated kidney, soy and Barrio rice. Polyunsaturated fatty acids (PUFA) increased in some germinated samples (mung bean, peanut, red, brown, Barrio and white rice) but decreased in other legume and rice samples. Generally, palmitic acid increased while stearic, oleic and linoleic acids decreased after germination. Overall, the proximate content and fatty acids of legume and rice varieties changed after germination and may be used as alternate resources for individuals with lifestyle diseases.
Roasting of whole-kernels is an important step in the production of pistachio paste. The effect of hot air roasting temperatures (90-190°C) and times (5-65 min) on the hardness, moisture content and colour attributes (‘L’, ‘a’ and ‘b’ values and yellowness index) of both whole-kernel and ground-state were investigated using response surface methodology (RSM). Increases in roasting temperature and time caused a decrease in all the responses except for ‘a’ value of ground-state. The interaction and quadratic models sufficiently described the changes in the hardness and colour values, respectively. The result of RSM analysis showed that hardness and colour attributes (‘L’ and ‘b’ values, yellowness index) of kernels and ‘a’ value of ground-state could be used to monitor the roasting quality of whole-kernels. This study showed that the recommended range of roasting temperature and time of whole-kernel for the production of pistachio paste were 130-140°C and 30-40 min, respectively.
The ability to compare bovine and porcine skin gelatin based on their amino acid composition, polypeptides pattern, bloom strength, turbidity and foaming properties were investigated. Amino acid composition of both gelatin showed that the content of glycine, proline and arginine in porcine gelatin were higher than bovine gelatin. However, the polypeptides pattern between both gelatin is closely similar. The bloom strength of porcine gelatin was higher than bovine gelatin from pH 3 to pH 10. Both gelatin possessed highest bloom strength at pH 9. The lowest bloom strength of bovine gelatin was at pH 3 while porcine gelatin at pH 5. The highest turbidity of bovine gelatin obtained at pH 7 while porcine gelatin at pH 9. Foam expansion and foam stability of bovine gelatin were higher than porcine gelatin at all concentrations.
The aim of this study is to compare the occurrence of thermophilic Campylobacter spp. in chicken retail at wet markets and hypermarkets. Campylobacter contaminations in chicken samples from wet market (70.7%) were comparatively lower than chicken samples sold in hypermarket (91.4%). Of the 77 Campylobacter isolates, 59 (76.6%) were identified as Campylobacter jejuni and 18 (23.4%) isolates were identified as C. coli. All Campylobacterisolates are multi-resistant to the antimicrobial agents. Most of the isolates were resistant to tetracycline (92.2%) and erythromycin (98.7%). This study concluded that chicken samples from both wet market and hypermarket were contaminated with Campylobacter, most of which are antimicrobial-resistant strains.
Vibrio cholerae still represents a significant threat to human health worldwide despite the advances in hygiene, consumer knowledge, food treatment and food processing. In Malaysia, statistics in year 2009 have shown that among the food and water borne diseases, food poisoning has the highest incidence rate of 36.17 per 100,000 populations and with a mortality rate of 0.01 per 100,000 populations. In this study, 22 seafood samples comprising of fish, squid, crustacean and mollusks purchased from wet market and supermarket were analyzed. The Most Probable Number (MPN) and real time PCR was used to enumerate the Vibrio cholerae in seafood sample. The results showed that MPN-real time PCR of the samples from wet market had a maximum of >1100 MPN/g compare to 93 MPN/g enumerated from the MPN plate. The MPN-real time PCR in the samples from supermarket indicated 290 MPN/g as compared to 240 MPN/g enumerated from the MPN plate. The standard curves showed that there was a good linear correlation between the Ct values. The minimum level of detection of Vibrio cholerae standard DNA at targeted gene was 3 x 10-5 ng/μl.
This research was to determine nutritional composition, essential and toxic elemental content, and major phenolic acid with antioxidant activity in Kadsura coccinea fruit. The results indicated that Kadsura coccinea fruit exhibited the high contents of total protein, total fat, ash and essential elements such as calcium (Ca), ferrum (Fe) and phosphorus (P). The levels of four common toxic elements, i.e. cadmium (Cd), mercury (Hg), arsenic (As) and lead (Pb), were lower than legal limits. By high-performance liquid chromatography (HPLC) analysis, gallic acid was identified as major phenolic acid in peel and pulp tissues. Its contents were no significant difference in both tissues. In comparison with two commercial antioxidants, the major phenolic acid extracted from Kadsura coccinea exhibited stronger 1,1-diphenyl-2-picrylhydrazyl radical-scavenging activity and reducing power. Kadsura coccinea fruit is a good source of nutrition and natural antioxidant. It is worthwhile to popularize this exotic fruit around the world.
The effects of washing treatments and washing cycles on the thermal gelation properties and quality
characteristics of duckrimi (duck-base surimi-like material) were evaluated. Minced spent layer duck (4.5 mm orifice diameter) were washed by using either tap water, 0.1M NaCl, 0.5% NaHCO3 and 0.04M sodium phosphate in one, two or three washing cycles, respectively. Washing with 0.04M sodium phosphate in three washing cycles significantly increased (P
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.
The ability to detect the presence of transgenes in crop-derived foods depends on the quantity and quality of DNA obtained from a product to be analyzed. The efficiency of DNA extraction protocols differs due to the nature of each food product. In this paper, we described two main DNA extraction protocols and their modifications that have been applied and evaluated for DNA extraction from raw and processed food as well as animal feed. The yield and quality for five categories of food and feed samples namely, raw soybean, raw maize, animal feed, smooth tofu and soymilk are discussed. The statistical interaction analyses showed that the cetyltrimethyl ammonium bromide (CTAB) method was proven to be the best method to extract DNA from raw soybean, maize and animal feed samples which not only obtained high DNA yield of 32.7, 28.4 and 33.4 ng DNA/mg sample respectively, but also produced high quality DNA with the absorbance A260/A280 ratio of 1.9, 1.9 and 2.0, respectively. These DNA were suitable for PCR amplification which produced a 164 bp DNA fragment of the lectin gene from soybean, and a 277 bp DNA fragment of the zein gene from maize. In the processed food category, the Wizard isolation method was found to be the best for the extraction of DNA from smooth tofu and soymilk with the yield of 13.2 and 3.4 ng DNA/mg sample, and the quality of the DNA at the absorbance A260/A280 ratio ranged from 1.9 to 1.7. These DNA were successfully amplified using primers specific to the lectin gene of soybean.
Several blends of cellulose derived from bast part of kenaf (Hibiscus cannabinus L.) plant, with different thermoplastics, low density polyethylene (LDPE) and high density polyethylene (HDPE), were prepared by a melt blending machine. Polyethylene glycol (PEG) was used as plasticizer. Biodegradability of these blends was measured using soil burial test in order to study the rates of biodegradation of these polymer blends. It was found that the cellulose/LDPE and cellulose/HDPE blends were biodegradable in a considerable rate. The bio-composites with high content of cellulose had higher degradation rate. In addition, biodegradability of the bio-composites made up using PEG was superior to those of the bio-composites fabricated without PEG, due to the improved wetting of the plasticizer in the matrix polymer. The results were also supported by the scanning electron microscopy (SEM).
Food labeling in accordance with Novel Food Regulation has been enforced in the European Community since 1997 with a series of updated legislations namely, EC/258/97, EC/1139/98, EC/49/2000, EC/50/2000 and EC/1829/2003. Guidelines and labeling regulations for the use of GMOs materials in food and feed products has also been introduced in Malaysia and Vietnam. Therefore, the demand for the establishment and development of a robust and rapid operation procedure for GMO detection has increased recently in both countries. The procedure of GMO detection emphasizes not only on detection tests but also on confirmation assays. This study employed PCR technology for detection and direct DNA sequencing for confirmation procedures respectively. The results demonstrated for the first time the presence of GM plants with glyphosate-resistant trait led by the control of P35S promoter and NOS terminator in either Malaysian or Vietnamese feed with high frequency (20 positive samples out of 24 analyzed samples). The P35S promoter, EPSPS gene and NOS terminator sequences obtained showed some mutations on single-stranded and double-stranded targeted sequences caused by single nucleotide insertion or single nucleotide changes. These results reinforce the need for development of detection procedures to comply with food/feed labeling system.
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.