A disposable screen-printed e-tongue based on sensor array and pattern recognition that is suitable for the assessment of water quality in fish tanks is described. The characteristics of sensors fabricated using two kinds of sensing materials, namely (i) lipids (referred to as Type 1), and (ii) alternative electroactive materials comprising liquid ion-exchangers and macrocyclic compounds (Type 2) were evaluated for their performance stability, sensitivity and reproducibility. The Type 2 e-tongue was found to have better sensing performance in terms of sensitivity and reproducibility and was thus used for application studies. By using a pattern recognition tool i.e. principal component analysis (PCA), the e-tongue was able to discriminate the changes in the water quality in tilapia and catfish tanks monitored over eight days. E-tongues coupled with partial least squares (PLS) was used for the quantitative analysis of nitrate and ammonium ions in catfish tank water and good agreement were found with the ion-chromatography method (relative error, ±1.04- 4.10 %).
MeSH terms: Animals; Catfishes; Chromatography; Monosaccharides; Oligopeptides; Water; Reproducibility of Results; Least-Squares Analysis; Tilapia; Motor Vehicles; Principal Component Analysis; Macrocyclic Compounds; Water Quality; Ammonium Compounds
Magnetic nanoparticles of Fe₃O₄ were synthesized and characterized using transmission electron microscopy and X-ray diffraction. The Fe₃O₄ nanoparticles were found to have an average diameter of 5.48 ±1.37 nm. An electrochemical biosensor based on immobilized alkaline phosphatase (ALP) and Fe₃O₄ nanoparticles was studied. The amperometric biosensor was based on the reaction of ALP with the substrate ascorbic acid 2-phosphate (AA2P). The incorporation of the Fe₃O₄ nanoparticles together with ALP into a sol gel/chitosan biosensor membrane has led to the enhancement of the biosensor response, with an improved linear response range to the substrate AA2P (5-120 μM) and increased sensitivity. Using the inhibition property of the ALP, the biosensor was applied to the determination of the herbicide 2,4-dichlorophenoxyacetic acid (2,4-D). The use of Fe₃O₄ nanoparticles gives a two-fold improvement in the sensitivity towards 2,4-D, with a linear response range of 0.5-30 μgL-1. Exposure of the biosensor to other toxicants such as heavy metals demonstrated only slight interference from metals such as Hg2+, Cu2+, Ag2+ and Pb2+. The biosensor was shown to be useful for the determination of the herbicide 2, 4-D because good recovery of 95-100 percent was obtained, even though the analysis was performed in water samples with a complex matrix. Furthermore, the results from the analysis of 2,4-D in water samples using the biosensor correlated well with a HPLC method.
The role of incorporation of gold nanoparticles (50-130 nm in diameter) into a series of photocurable methacrylic-acrylic based biosensor membranes containing tyrosinase on the response for phenol detection was investigated. Membranes with different hydrophilicities were prepared from 2-hydroxyethyl methacrylate and n-butyl acrylate via direct photocuring. A range of gold nanoparticles concentrations from 0.01 to 0.5 % (w/w) was incorporated into these membranes during the photocuring process. The addition of gold nanoparticles to the biosensor membrane led to improvement in the response time by a reduction of approximately 5 folds to give response times of 5-10 s. The linear response range of the phenol biosensor was also extended from 24 to 90 mM of phenol. The hydrophilicities of the membrane matrices demonstrated strong influence on the biosensor response and appeared to control the effect of the gold nanoparticles. For less hydrophilic methacrylic-acrylic membranes, the addition of gold nanoparticles led to a poorer sensitivity and detection limit of the biosensor towards phenol. Therefore, for the application of gold nanoparticles in the enhancement of a phenol biosensor response, the nanoparticles should be immobilized in a hydrophilic matrix rather than a hydrophobic material.
MeSH terms: Acrylates; Gold; Methacrylates; Reaction Time; Monophenol Monooxygenase; Biosensing Techniques; Phenol; Metal Nanoparticles; Limit of Detection; Hydrophobic and Hydrophilic Interactions
This paper discusses sputtered silicon encapsulation as a wafer level packaging approach for isolatable MEMS devices. Devices such as accelerometers, RF switches, inductors, and filters that do not require interaction with the surroundings to function, could thus be fully encapsulated at the wafer level after fabrication. A MEMSTech 50g capacitive accelerometer was used to demonstrate a sputtered encapsulation technique. Encapsulation with a very uniform surface profile was achieved using spin-on glass (SOG) as a sacrificial layer, SU-8 as base layer, RF sputtered silicon as main structural layer, eutectic gold-silicon as seal layer, and liquid crystal polymer (LCP) as outer encapsulant layer. SEM inspection and capacitance test indicated that the movable elements were released after encapsulation. Nanoindentation test confirmed that the encapsulated device is sufficiently robust to withstand a transfer molding process. Thus, an encapsulation technique that is robust, CMOS compatible, and economical has been successfully developed for packaging isolatable MEMS devices at the wafer level.
MeSH terms: Drug Packaging; Glass; Gold; Polymers; Silicon; Electric Capacitance; Micro-Electrical-Mechanical Systems; Accelerometry
Microbiological quality analysis of freshwater prawns from three sampling sites in Peninsular Malaysia viz: Site 1- Kg. Jumbang, Negri Sembilan; Site 2- Kg. Cangkat Tin, Perak and Site 3- Kg. Cenderiang, Perak for total mesophilic and psychrophilic aerobic counts, proteolytic bacterial counts, histamine producing bacteria, cadaverine producing bacteria and putrescine producing bacteria in the prawns and pond water for the three sites showed that the microbiological quality of freshwater prawns is related to the microflora of pond water in which they were grown. The initial bacterial counts indicated the values were in the range of log 4+ CFU/g for all samples. Total mesophilic and psychrophilic counts of the head regions were higher than that of the body regions for all prawn samples and types of growth media tested. All samples showed an increase in counts with time and temperature of storage up to log 7+ CFU/g for mesophilic counts after 12 hours at ambient, 6 days at 10 ± 2°C and 12 days at iced storage. The samples from Site 2 had relatively higher counts compared to the other two sites which correlated well with the levels determined in the pond water. Similar trends were observed for psychrophilic counts but at lower values for the different types of media studied.
Effects of preservatives on quality changes and shelf life of shrimp during iced storage indicated that boric acid, lactic acid and sodium metabisulphite managed to inhibit psychrophilic bacteria and biogenic amines formation in prawns while maintaining the mesophilic counts at lower levels during iced storage.
Pectin and modified pectin differ in the structure of the chains in which the modified version of pectin is shorter in length, non-branched, and galactose-rich. These differences in structure may be exploited for the removal of heavy metals. Durian (Durio zibethinus) rind, that is regarded as agri-food waste was processed into durian rind pectin (DRP) and modified durian rind pectin (mDRP). DRP and mDRP were evaluated as biosorbent for removal of toxic heavy metals (Pb(II), Cd(II), Cu(II), Zn(II) and Ni(II)) and were compared with two commercial products; citrus pectin (CP) and modified citrus pectin (MCP). In general, the order of removal of heavy metals by all biosorbents was Cu(II) > Pb(II) > Ni(II) > Zn > Cd(II). Except for the removal of Pb(II), the order of effectiveness of heavy metal removal of the biosorbents was MCP > mDRP > CP > DRP. MCP, a commercial biosorbent showed the best biosorbent ability, and mDRP a waste product from durian was also a favorable sorber that should be considered for sorption and removal of heavy metals.
Using the Malaysian Household Expenditure Survey 2004/2005 data, this study investigated Malaysian consumers’ preference for beef quantity, quality, and lean beef. Demand and price models that incorporated consumer socio-economic variables were estimated via two-stage least squares (2SLS). This study showed that Malaysian consumers tend to demand for more quantity rather than quality of beef products. Malaysian consumers are also more responsive to price changes rather than fat reduction in beef products. It is more profitable for beef market players to increase their production as Malaysian consumers are expected to consume increasing amounts of beef products.
MeSH terms: Red Meat; Animals; Cattle; Commerce; Consumer Behavior; Health Expenditures; Meat; Surveys and Questionnaires; Least-Squares Analysis; Biological Processes
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.
The objective of the study was to investigate the hypoglycaemic properties of Malaysian cocoa (Theobroma cacao) polyphenols extract in-vivo and insulin sensitivity in-vitro. Cocoa extract (CE) (containing 190 - 286 mg total polyphenol per gram extract) was prepared from fermented and roasted (140°C, 20 min) beans by extracting with 80% ethanol in the ratio of 1 to 10. For the in-vivo study, the CE was administered in three dosages (1%, 2%, and 3%) to groups of normal and diabetic rats for a period of 4 weeks by forcefeeding. Results showed that dosages of 1% and 3% CE significantly reduced (p < 0.05) plasma glucose levels in the diabetic rats. An in-vitro study (BRIN-BD11 cell lines) was used to evaluate the effect of CE on insulinsensitivity. The results demonstrated that CE at a concentration of 0.1 mg/ml significantly increased (p < 0.05) insulin level compared to the control. The results of this study showed that Malaysian cocoa polyphenol extract have the potential of being an insulin-mimetic agent. Further studies are on-going to elucidate the underlying mechanisms of polyphenols present in CE that contribute to the reduction of plasma glucose levels and insulin mimicking activity.
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.
MeSH terms: Ampicillin; Anti-Bacterial Agents; Bacitracin; Carbenicillin; Ceftriaxone; Cefuroxime; Cephalothin; Gentamicins; Kanamycin; Malaysia; Nalidixic Acid; Penicillin G; Protein Synthesis Inhibitors; Polymorphism, Restriction Fragment Length; Streptomycin; Sulfamethoxazole; Tetracycline; Deoxyribonucleases, Type II Site-Specific; Incidence; Polymerase Chain Reaction; Pectobacterium chrysanthemi; Ananas
Food and fuel prices have soared in recent years affecting most adversely the poor and those with fixed incomes. Since 2000, wheat price in the international market has more than tripled and maize prices have more than doubled. The price of rice, the staple of billions in Asia, has tripled in the past year. The surge of food prices has been blamed on multiple factors including higher energy and fertilizer costs, greater global demand, drought, the loss of arable land to biofuel crops and price speculation. In light of the spiraling rise in food prices, there is the prospect of increasing rates of under-nutrition worldwide. As it is, 800 million are estimated to be suffering from chronic malnourishment, with another 2.1 billion people living close to subsistence levels on less than US$2 a day. Some perspectives of the food production experience of Malaysia are shared here as a case of a country that has built up capabilities and resources through high level of foreign and domestic investment leading to a diversified economy. In response to the recent surge in the price of rice, the Malaysian government announced the setting up of a dedicated fund amounting to US$1.25 billion to increase production of food including fruits and vegetables, and targeting 100% self-sufficiency in rice, by growing rice on a massive scale in Sarawak. During the current five-year development plan for the period of 2006-2010, (Ninth Malaysia Plan), the role of the agriculture sector is considerably enhanced to be the third pillar of economic growth, after manufacturing and services. Among the measures taken, are those aimed at increasing incomes of smallholders and fishermen mainly through improving productivity. These measures include encouraging more rice farmers to participate in mini-estates and group farming, providing financial assistance to rehabilitate cocoa, pepper and sago smallholdings, enhancing the capabilities of coastal fishermen, and setting up of a special program to assist poor households in the agriculture sector to diversify their sources of income. The various socio-economic programs in Malaysia that have been put in place over the years may have cushioned to some extent so far the severity of the dramatic hikes in food prices.
MeSH terms: Farmers; Agriculture; Asia; Cacao; Zea mays; Family Characteristics; Fertilizers; Financial Management; Fruit; Government; Investments; Malaysia; Oryza; Social Change; Vegetables; Triticum; Crops, Agricultural; Droughts; Biofuels; Economic Development
Antibacterial effect of modified sago starch-alginate edible film incorporating lemongrass oil at various concentrations was studied. Edible films were prepared from a mixture of modified sago starch and alginate. Lemongrass oil (0.1 - 0.4%, v/w) and glycerol (0 and 20%, w/w) were incorporated in the films to act as natural antimicrobial agent and plasticizer, respectively. The films were characterized for antibacterial activity against food pathogenic bacteria such as Escherichia coli O157:H7, Salmonella Enteritidis and Staphylococcus aureus. The edible film exhibited antibacterial activity against Escherichia coli O157:H7 and Salmonella Enteritidis by using agar diffusion assay method. For films tested against Escherichia coli O157:H7, the zone of inhibition increased significantly (p < 0.05) with addition of lemongrass oil at all levels both in the presence and absence of glycerol. The films also significantly (p < 0.05) inhibited the growth of Salmonella enteritidis only with 0.4% lemongrass oil (in the presence and absence of glycerol). However, the films containing lemongrass oil did not show any inhibition effect on Staphylococcus aureus.
Consumers are reported to be increasingly concerned about their health. Nonetheless, consumers show different attitudes toward food at home and away from home. In particular, consumers tend to shy away from healthy food items when dining on special occasions. This study is the first to look into the number of healthy menu items provided to consumers during dining occasions. The impacts of two independent variables (dining occasion: normal vs. special; number of healthy items: limited vs. extended) on consumers’ dining menu selection was examined among female university students. The results of this study indicate that both dining occasion and the number of healthy items offered could influence consumers’ food selection independently. Although consumers are more likely to choose unhealthy items while dining’on special occasions, offering more healthy items would increase the probability of healthy eating. This study also offers some insights into the food categories and cooking methods favored by consumers. Further studies should explore other potential foods that would enhance the selection of healthy options by consumers.
Four types of soft dates (SD), three types of semi-dried dates (SDD) and one type of dried dates (DD) were used in this study. The antioxidant activities were assessed using TEAC method (ABTS assay) and the ferric reducing/antioxidant power method (FRAP assay), while total phenolic content (TPC) and total flavonoid content (TFC) were measured using Folin-Ciocalteau and aluminum chloride colorimetric methods. Multivariate analysis of variance (MANOVA), discriminant analysis (DA) and principal component analysis (PCA) were used to analyze the data. MANOVA showed a strong significant difference between the eight types of dates. DA identified the relative contribution of each parameter in distinguishing the dates. DA also identified two functions responsible for discriminating the dates and showed the difference between different types of dates. The first function distinguished DD from other types of dates, whilst the second function discriminated SD and SDD, affording 100% correct assignation. PCA identified only one component responsible for explaining 98.85% of the total variance in antioxidant data. It is suggested that the TEAC method and the quantitative determination of TPC and TFC was suitable for differentiation of dates and quality control.
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.
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.
MeSH terms: Base Sequence; DNA; European Union; Food Labeling; Glycine; Malaysia; Mutation; Nucleotides; Terminator Regions, Genetic; Vietnam; Polymerase Chain Reaction; Sequence Analysis, DNA
Antibiotic resistance in campylobacter is an emerging global public health problem after MRSA and VRE. Fluoroquinolone and macrolide resistance have been found to be more common in this world leading foodborne pathogen. A total of fifty-six isolates of Campylobacter jejuni obtained from raw vegetables
which are consumed as ulam (salad) in Malaysia, were tested with 12 antibiotics used clinically and
agriculturally. The resistance was determined using the disk diffusion method. Results were determined
by hierarchic numerical methods to cluster strains and antibiotics according to similarity profiles. Fifty
five C. jejuni isolates from different isolation sites were all clustered together into ten groups. This indicates that the commodities (raw salad vegetables/ulam) where the isolates originated might share a similar source of cross-contamination along the production route. All antibiotics tested correlated and there were four groupings reflecting their mode of actions. Generally, C. jejuni isolates were found to be highly resistant to erythromycin (91.1%) and tetracycline (85.7%). Both agents are popular antibiotics used clinically to treat bacterial infections. On the other hand, the C. jejuni isolates showed high percentage (80.4%) of resistance towards enrofloxacin, an extensively used antimicrobial agent in agriculture practices. This study showed that C. jejuni isolates were highly multi-resistance to as many as 10 antibiotics. Therefore, in terms of biosafety, the presence of antibiotic resistance strains in the food chain has raised concerns that the treatment of human infections will be compromised.
Evaluation on the physicochemical and sensory properties of wheat flour doughnuts substituted with banana flour (BF) was investigated. Wheat flour was substituted with green banana (Musa paradisiaca var. Awak) flour at 0% (control), 10%, 20% and 30% levels in yeast-raised doughnut prepared by the straight dough method. Chemical (moisture, fat, protein, ash, carbohydrate, crude fibre, total dietary fibre and caloric content), physical (volume, specific volume and colour) and sensory evaluation were conducted on all samples. Chemical analyses result indicated a higher percentage of total dietary fibre and caloric content in doughnut substituted with BF than the control. Colour evaluation showed that the dough, crust and crumb of doughnut with BF ranged from 68.97 ± 0.59 – 84.78 ± 0.16 (red – yellow quadrant). The change from light to darker colour correlated with the amount of BF added. Results also showed that the volume and specific volume was significantly affected (p < 0.05) by levels of BF substituted. Doughnut substituted with 20% BF showed the highest score in overall acceptability (6.71 ± 1.40).
The level of total lipid and oryzanol content, an important antioxidant compound in locally produced bran was investigated. Total lipid in rice bran was extracted using 3:2 chloroform:methanol mixture yielding 16.4% fat. Oryzanol content was determined without saponification using a reverse-phase HPLC. Four fractions of oryzanol were successfully separated and quantitated. The 4 isomers were cycloartenyl ferulate, 24-methylene cycloartanyl ferulate, campestryl ferulate and mixtures of β–sitosteryl ferulate and cycloartanyl ferulate. The oryzanol content of local mixed varieties ranged from 23.7–43.0 mg g-1. The oryzanol concentration may depend on factors such as plant varieties, processing methods employed, extracting solvent used and ratio of extracting solvent to bran as well as extracting solvent temperatures. This study showed the potential of oryzanol extract from rice bran as a source of antioxidant.
MeSH terms: Methanol; Antioxidants; Chloroform; Chromatography, High Pressure Liquid; Coumaric Acids; Lipids; Phenylpropionates; Oryza; Solvents; Temperature
A total of 78 samples comprising different types of street foods, sold in different locations in Malaysia, were examined for the presence of Enterobacter cloacae. E. cloacae contamination was recorded in 9% of the samples examined. Tests for susceptibility to 12 different antibiotics showed that all were resistant to six or more antibiotics, but susceptible to chloramphenicol and gentamicin. Plasmids of four different sizes were detected from the three plasmid positive isolates. RAPD analysis using four primers yielded completely different banding patterns for all E. cloacae studied. In Malaysia, no published information on street foods in the epidemiological investigation of E.cloacae related disease is available. However, their occurrences have provided compelling evidence that the risk of disease transmission caused by E. cloacae through street foods is moderate.
MeSH terms: Animals; Anti-Bacterial Agents; Chloramphenicol; Cloaca; Gentamicins; Malaysia; Plasmids; Enterobacter cloacae; DNA Primers; Random Amplified Polymorphic DNA Technique