Displaying publications 1 - 20 of 183 in total

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  1. Antimicrobial effects of Caulerpa sertularioides extract on foodborne diarrhea-caused bacteria
    Darah I, Tong WY, Nor-Afifah S, Nurul-Aili Z, Lim SH
    Eur Rev Med Pharmacol Sci, 2014;18(2):171-8.
    PMID: 24488904
    Caulerpa (C.) sertularioides has many therapeutic uses in the practice of traditional medicine in Malaysia. Crude methanolic, diethyl ether extract, ethyl acetate extract and butanolic extract from C. sertularioides were subjected to antimicrobial screening including the three Gram-positive and three Gram-negative diarrhea-caused bacteria.
    Matched MeSH terms: Food Microbiology
  2. Fulltext Probiotic Properties of Exopolysaccharide-Producing Lactobacillus Strains Isolated from Tempoyak
    Khalil ES, Abd Manap MY, Mustafa S, Alhelli AM, Shokryazdan P
    Molecules, 2018 Feb 13;23(2).
    PMID: 29438288 DOI: 10.3390/molecules23020398
    Tempoyak is a functional Malaysian food (an acid-fermented condiment) which is produced from the pulp of the durian (Durio zibethinus) fruit. The current study aimed to isolate and identify potential exopolysaccharide (EPS)-producing Lactobacillus strains from tempoyak for potential use as probiotics. Seven isolates (DUR2, DUR4, DUR5, DUR8, DUR12, DUR18, and DUR20) out of 44 were able to produce EPS, and exhibited resistance to acid and bile salt compared to the reference strains Lactobacillus rhmnosus (ATCC53103) and L. plantarum (ATCC8014). The seven isolated strains belonged to five different species-L. plantarum, L. fermentum, L. crispatus, L. reuteri, and L. pentosus-which were identified using API 50 CHL and 16S rRNA gene sequences (Polymerase chain reaction, PCR - based). The seven strains displayed different ability to produce EPS (100-850 mg/L). Isolates exhibited a high survivability to acid (pH 3.0), bile salts (0.3%), and gastrointestinal tract model (<70%). Results showed that the auto-aggregation and cell surface hydrophobicity ranged from 39.98% to 60.09% and 50.80% to 80.53%, respectively, whereas, the highest co-aggregation value (66.44%) was observed by L. fermentum (DUR8) with Pseudomonas aeruginosa. The isolates showed good inhibitory activity against tested pathogens, high antioxidant activity (32.29% to 73.36%), and good ability to reduce cholesterol (22.55% to 75.15%). Thus, the seven tested strains have value as probiotics.
    Matched MeSH terms: Functional Food/microbiology*
  3. Antibacterial activity of Lactobacillus acidophilus strains isolated from honey marketed in Malaysia against selected multiple antibiotic resistant (MAR) Gram-positive bacteria
    Aween MM, Hassan Z, Muhialdin BJ, Eljamel YA, Al-Mabrok AS, Lani MN
    J Food Sci, 2012 Jul;77(7):M364-71.
    PMID: 22757710 DOI: 10.1111/j.1750-3841.2012.02776.x
    A total of 32 lactic acid bacteria (LAB) were isolated from 13 honey samples commercially marketed in Malaysia, 6 strains identified as Lactobacillus acidophilus by API CHL50. The isolates had antibacterial activities against multiple antibiotic resistant's Staphylococcus aureus (25 to 32 mm), Staphylococcus epidermis (14 to 22 mm) and Bacillus subtilis (12 to 19 mm) in the agar overlay method after 24 h incubation at 30 °C. The crude supernatant was heat stable at 90 °C and 121 °C for 1 h. Treatment with proteinase K and RNase II maintained the antimicrobial activity of all the supernatants except sample H006-A and H010-G. All the supernatants showed antimicrobial activities against target bacteria at pH 3 and pH 5 but not at pH 6 within 72 h incubation at 30 °C. S. aureus was not inhibited by sample H006-A isolated from Libyan honey and sample H008-D isolated from Malaysian honey at pH 5, compared to supernatants from other L. acidophilus isolates. The presence of different strains of L. acidophilus in honey obtained from different sources may contribute to the differences in the antimicrobial properties of honey.
    Matched MeSH terms: Food Microbiology
  4. Locally isolated yeasts from Malaysia: identification, phylogenetic study and characterization
    Oslan SN, Salleh AB, Rahman RN, Basri M, Chor AL
    Acta Biochim. Pol., 2012;59(2):225-9.
    PMID: 22577620
    Yeasts are a convenient platform for many applications. They have been widely used as the expression hosts. There is a need to have a new yeast expression system to contribute the molecular cloning demands. Eight yeast isolates were screened from various environment sources and identified through ribosomal DNA (rDNA) Internal Transcribed Spacer (ITS). Full sequence of the rDNA ITS region for each isolate was BLASTed and phylogenetic study was constructed by using MEGA4. Among the isolates, isolate WB from 'ragi' (used to ferment carbohydrates) could be identified as a new species in order Saccharomycetales according to rDNA ITS region, morphology and biochemical tests. Isolate SO (from spoiled orange), RT (rotten tomato) and RG (different type of 'ragi') were identified as Pichia sp. Isolates R1 and R2, S4 and S5 (from the surrounding of a guava tree) were identified as Issatchenkia sp. and Hanseniaspora sp., respectively. Geneticin, 50 µg/mL, was determined to be the antibiotic marker for all isolates excepted for isolates RT and SO which used 500 µg/mL and 100 µg/mL Zeocin, respectively. Intra-extracellular proteins were screened for lipolytic activity at 30°C and 70°C. Thermostable lipase activity was detected in isolates RT and R1 with 0.6 U/mg and 0.1 U/mg, respectively. In conclusion, a new yeast-vector system for isolate WB can be developed by using phleomycin or geneticin as the drugs resistance marker. Moreover, strains RT and R1 can be investigated as a novel source of a thermostable lipase.
    Matched MeSH terms: Food Microbiology
  5. Genotypic and phenotypic differentiation of Salmonella enterica serovar Paratyphi B in Malaysia
    Thong KL, Ang CP
    Southeast Asian J. Trop. Med. Public Health, 2011 Sep;42(5):1178-89.
    PMID: 22299444
    Abstract. Salmonella enterica serovar Paratyphi B is known to cause either paratyphoid fever or gastroenteritis. Differentiation of Salmonella ser. Paratyphi B into biotype Java (d-tartrate fermenting, dT+) and biotype Paratyphi B (d-tartrate non-fermenting, dT) is important for Salmonella epidemiology. This study applied a PCR approach to differentiate the two biotypes to augment the conventional biochemical method and to determine the antibiograms and genomic diversity of Malaysian S. Paratyphi B. Among 100 strains tested (clinical, 86; non-humans, 14), only two clinical strains were confirmed as biotype Paratyphi B as indicated by both lead acetate test and PCR. Antibiotic resistance rates were as follows: streptomycin 18%, sulphonamides 13%, ampicillin 10%, chloramphenicol 4%, tetracycline 3%, cefotaxime 2%, cefpodoxime 2%, ceftazidime 2%, gentamicin 1% and trimethoprim 1%. None showed resistance towards amoxicillin-clavulanic acid, ceftiofur, ciprofloxacin, nalidixic acid and trimethoprim-sulphamethoxazole. Seven strains showed multidrug resistance towards 3 or more classes of antimicrobial agents. REP-PCR and PFGE generated 32 and 76 different profiles, respectively. PFGE (D = 0.99) was more discriminative than REP-PCR (D = 0.93) and antimicrobial susceptibility test (D = 0.48) in subtyping the strains. Strains isolated 18 years apart (1982 - 2008) from different localities in Malaysia were clonally related as demonstrated by REP-PCR and PFGE, indicating that these strains were stable and widely distributed. In some clusters, strains isolated from different sources (clinical, food and animal) were grouped together. Thus, biotype Java was the most common biotype of Salmonella ser. Paratyphi B in Malaysia. The PCR approach is highly recommended due to its simplicity, specificity and ease of operation. The level of antimicrobial resistance among Salmonella ser. Paratyphi B remained relatively low in Malaysia but the emergence of resistance to cephalosporins is a cause for concern.
    Matched MeSH terms: Food Microbiology
  6. Analysis of Salmonella Agona and Salmonella Weltevreden in Malaysia by PCR fingerprinting and antibiotic resistance profiling
    Learn-Han L, Yoke-Kqueen C, Salleh NA, Sukardi S, Jiun-Horng S, Chai-Hoon K, et al.
    Antonie Van Leeuwenhoek, 2008 Oct;94(3):377-87.
    PMID: 18548329 DOI: 10.1007/s10482-008-9254-y
    Forty-eight strains of Salmonella enterica subsp. enterica serovar Agona and 33 strains of Salmonella enterica subsp. enterica serovar Weltevreden were characterized by random amplified polymorphic DNA (RAPD) fingerprinting using 3 different arbitrary primer, Enterobacterial Repetitive Intergenic Consensus-Polymerase Chain Reaction (ERIC-PCR) and antimicrobial susceptibility testing. By using RAPD, 81 strains (44 strains of S. Agona and 33 strains of S. Weltevreden) can be clustered into 14 groups and 6 single isolates whereas ERIC-PCR produced 7 clusters and 3 single isolates. Thirteen antimicrobial agents were used and all the isolates were resistant to erythromycin and showed Multiple Antimicrobial Resistance indexes, ranging from 0.08 to 0.62. Poultry still remain as the common reservoir for multi-drug-resistant Salmonella. On the other hand, vegetables contaminated with S. Weltevreden showed a gain in antimicrobial resistance. Besides that, consistent antibiograms were observed from S. Weltevreden isolated at Kajang wet market on 2000/08/02.
    Matched MeSH terms: Food Microbiology
  7. Fulltext Physicochemical and antioxidant properties of Malaysian honeys produced by Apis cerana, Apis dorsata and Apis mellifera
    Moniruzzaman M, Khalil MI, Sulaiman SA, Gan SH
    BMC Complement Altern Med, 2013;13:43.
    PMID: 23433009 DOI: 10.1186/1472-6882-13-43
    The aim of the present study was to evaluate the physicochemical and antioxidant properties of Malaysian monofloral honey samples-acacia, pineapple and borneo honey-and compare them with tualang honey. Acacia and pineapple honey are produced by Apis mellifera bees while borneo and tualang honey are produced by Apis cerana and Apis dorsata bees, respectively.
    Matched MeSH terms: Food Microbiology
  8. Fulltext Titanium Dioxide Nanoparticle-Based Interdigitated Electrodes: A Novel Current to Voltage DNA Biosensor Recognizes E. coli O157:H7
    Nadzirah Sh, Azizah N, Hashim U, Gopinath SC, Kashif M
    PLoS One, 2015;10(10):e0139766.
    PMID: 26445455 DOI: 10.1371/journal.pone.0139766
    Nanoparticle-mediated bio-sensing promoted the development of novel sensors in the front of medical diagnosis. In the present study, we have generated and examined the potential of titanium dioxide (TiO2) crystalline nanoparticles with aluminium interdigitated electrode biosensor to specifically detect single-stranded E.coli O157:H7 DNA. The performance of this novel DNA biosensor was measured the electrical current response using a picoammeter. The sensor surface was chemically functionalized with (3-aminopropyl) triethoxysilane (APTES) to provide contact between the organic and inorganic surfaces of a single-stranded DNA probe and TiO2 nanoparticles while maintaining the sensing system's physical characteristics. The complement of the target DNA of E. coli O157:H7 to the carboxylate-probe DNA could be translated into electrical signals and confirmed by the increased conductivity in the current-to-voltage curves. The specificity experiments indicate that the biosensor can discriminate between the complementary sequences from the base-mismatched and the non-complementary sequences. After duplex formation, the complementary target sequence can be quantified over a wide range with a detection limit of 1.0 x 10(-13)M. With target DNA from the lysed E. coli O157:H7, we could attain similar sensitivity. Stability of DNA immobilized surface was calculated with the relative standard deviation (4.6%), displayed the retaining with 99% of its original response current until 6 months. This high-performance interdigitated DNA biosensor with high sensitivity, stability and non-fouling on a novel sensing platform is suitable for a wide range of biomolecular interactive analyses.
    Matched MeSH terms: Food Microbiology
  9. Microbial analysis of Malaysian tempeh, and characterization of two bacteriocins produced by isolates of Enterococcus faecium
    Moreno MR, Leisner JJ, Tee LK, Ley C, Radu S, Rusul G, et al.
    J Appl Microbiol, 2002;92(1):147-57.
    PMID: 11849339
    Isolation of bacteriocinogenic lactic acid bacteria (LAB) from the Malaysian mould-fermented product tempeh and characterization of the produced bacteriocin(s).
    Matched MeSH terms: Food Microbiology
  10. Genetic characterization of Escherichia coli O157: H7/- strains carrying the stx2 gene but not producing Shiga toxin 2
    Koitabashi T, Vuddhakul V, Radu S, Morigaki T, Asai N, Nakaguchi Y, et al.
    Microbiol. Immunol., 2006;50(2):135-48.
    PMID: 16490932
    Nine Escherichia coli O157: H7/- strains isolated primarily from non-clinical sources in Thailand and Japan carried the stx(2) gene but did not produce Stx2 toxin in a reversed passive latex agglutination (RPLA) assay. A strain (EDL933) bearing a stx(2) phage (933W) was compared to a strain (Thai-12) that was Stx2-negative but contained the stx(2) gene. To study the lack of Stx2 production, the Thai-12 stx(2) gene and its upstream nucleotide sequence were analyzed. The Thai-12 stx(2) coding region was intact and Stx2 was expressed from a cloned stx(2) gene using a plasmid vector and detected using RPLA. A lacZ fusion analysis found the Thai-12 stx(2) promoter non-functional. Because the stx(2) gene is downstream of the late promoter in the stx(2) phage genome, the antitermination activity of Q protein is essential for strong stx(2) transcription. Thai-12 had the q gene highly homologous to that of Phi21 phage but not to the 933W phage. High-level expression of exogenous q genes demonstrated Q antitermination activity was weak in Thai-12. Replication of stx(2) phage was not observed in Stx2-negative strains. The q-stx(2) gene sequence of Thai-12 was well conserved in all Stx2-negative strains. A PCR assay to detect the Thai-12 q-stx(2) sequence demonstrated that 30% of O157 strains from marketed Malaysian beef carried this sequence and they produced little or no Stx2. These results suggest that stx(2)-positive O157 strains that produce little or no Stx2 may be widely distributed in the Asian environment.
    Matched MeSH terms: Food Microbiology
  11. From farm to fork: identical clones and Tn6674-like elements in linezolid-resistant Enterococcus faecalis from food-producing animals and retail meat
    Elghaieb H, Tedim AP, Abbassi MS, Novais C, Duarte B, Hassen A, et al.
    J Antimicrob Chemother, 2020 01 01;75(1):30-35.
    PMID: 31605129 DOI: 10.1093/jac/dkz419
    OBJECTIVES: Increasing numbers of linezolid-resistant Enterococcus carrying optrA are being reported across different niches worldwide. We aimed to characterize the first optrA-carrying Enterococcus faecalis obtained from food-producing animals and retail meat samples in Tunisia.

    METHODS: Seven optrA-carrying E. faecalis obtained from chicken faeces (n=3, August 2017) and retail chicken meat (n=4, August 2017) in Tunisia were analysed. Antimicrobial susceptibility was determined by disc diffusion, broth microdilution and Etest against 13 antibiotics, linezolid and tedizolid, respectively (EUCAST/CLSI). optrA stability (∼600 bacterial generations), transfer (filter mating) and location (S1-PFGE/hybridization) were characterized. WGS (Illumina-HiSeq) was done for four representatives that were analysed through in silico and genomic mapping tools.

    RESULTS: Four MDR clones carrying different virulence genes were identified in chicken faeces (ST476) and retail meat (the same ST476 clone plus ST21 and ST859) samples. MICs of linezolid and tedizolid were stably maintained at 8 and 1-2 mg/L, respectively. optrA was located in the same transferable chromosomal Tn6674-like element in ST476 and ST21 clones, similar to isolates from pigs in Malaysia and humans in China. ST859 carried a non-conjugative plasmid of ∼40 kb with an impB-fexA-optrA segment, similar to plasmids from pigs and humans in China.

    CONCLUSIONS: The same chromosomal and transferable Tn6674-like element was identified in different E. faecalis clones from humans and animals. The finding of retail meat contaminated with the same linezolid-resistant E. faecalis strain obtained from a food-producing animal highlights the potential role of the food chain in the worrisome dissemination of optrA that can be stably maintained without selective pressure over generations.

    Matched MeSH terms: Food Microbiology
  12. Fulltext Artocarpus altilis extracts as a food-borne pathogen and oxidation inhibitors: RSM, COSMO RS, and molecular docking approaches
    Ahmad MN, Karim NU, Normaya E, Mat Piah B, Iqbal A, Ku Bulat KH
    Sci Rep, 2020 06 12;10(1):9566.
    PMID: 32533034 DOI: 10.1038/s41598-020-66488-7
    Lipid oxidation and microbial contamination are the major factors contributing to food deterioration. Food additives like antioxidants and antibacterials can prevent food spoilage by delaying oxidation and preventing the growth of bacteria. Artocarpus altilis leaves exhibited biological properties that suggested its use as a new source of natural antioxidant and antimicrobial. Supercritical fluid extraction (SFE) was used to optimize the extraction of bioactive compounds from the leaves using response surface methodology (yield and antioxidant activity). The optimum SFE conditions were 50.5 °C temperature, 3784 psi pressure and 52 min extraction time. Verification test results (Tukey's test) showed that no significant difference between the expected and experimental DPPH activity and yield value (99%) were found. Gas-chromatography -mass spectrometry (GC-MS) analysis revealed three major bioactive compounds existed in A. altilis extract. The extract demonstrated antioxidant and antibacterial properties with 2,3-diphenyl-1-picrylhydrazyl (DPPH) scavenging activity, ferric reducing ability of plasma (FRAP), hydroxyl radical scavenging activity, tyrosinase mushrrom inhibition of 41.5%, 8.15 ± 1.31 (µg of ascorbic acid equivalents), 32%, 37% and inhibition zone diameter of 0.766 ± 0.06 cm (B. cereus) and 1.27 ± 0.12 cm (E. coli). Conductor like screening model for real solvents (COSMO RS) was performed to explain the extraction mechanism of the major bioactive compounds during SFE. Molecular electrostatic potential (MEP) shows the probability site of nucleophilic and electrophilic attack during bacterial inhibition. Based on molecular docking study, non-covalent interactions are the main interaction occurring between the major bioactive compounds and bacteria (antibacterial inhibition).
    Matched MeSH terms: Food Microbiology
  13. Fulltext Prevalence of multidrug resistance Campylobacter jejuni and Campylobacter coli in chickens slaughtered in selected markets, Malaysia
    Mansouri-najand L, Saleha AA, Wai SS
    Trop Biomed, 2012 Jun;29(2):231-8.
    PMID: 22735845 MyJurnal
    The objectives of this study were to determine the occurrence of Campylobacter spp. in live chickens sold at wet markets in Selangor, Malaysia and the multidrug resistance (MDR) profiles of the isolates. Cloacal swabs were taken from the chickens before slaughter and their caecal mucosae were swabbed after slaughter. Of the 90 chickens examined, 68 (75.6%) were positive for Campylobacter. Campylobacter were recovered from caecal swabs (53/90) and cloacal swabs (34/90) and Campylobacter coli (46 isolates) were identified slightly more than Campylobacter jejuni (41 isolates), but these differences were not significant (p<0.05). The most frequently observed resistance was to cephalothin (95.5%), followed by tetracycline (80.8%), erythromycin (51.4%), enrofloxacin (42.4%) and gentamicin (24.4%). Multidrug resistance (resistant to four or more antibiotics) was detected in 35.3% isolates. Campylobacter jejuni showed nine resistance profiles and the most common was to gentamicin-eryhtromycin-enrofloxacin-cephalothin-tetracycline (32.4%) combination while C. coli showed six profiles, with cephalothin-tetracycline (32.2%) combination being most common.
    Matched MeSH terms: Food Microbiology
  14. Sennetsu neorickettsiosis: a probable fish-borne cause of fever rediscovered in Laos
    Newton PN, Rolain JM, Rasachak B, Mayxay M, Vathanatham K, Seng P, et al.
    Am J Trop Med Hyg, 2009 Aug;81(2):190-4.
    PMID: 19635868
    Neorickettsia sennetsu has been described from Japan and Malaysia, causing a largely forgotten infectious mononucleosis-like disease. Because it is believed to be contracted from eating raw fish, frequently consumed in the Lao PDR, we looked for evidence of N. sennetsu among Lao patients and fish. A buffy coat from 1 of 91 patients with undifferentiated fever was positive by 16S rRNA amplification and sequencing and real-time polymerase chain reactions (PCR) targeting two N. sennetsu genes. Lao blood donors and patients with fever, hepatitis, or jaundice (N = 1,132) had a high prevalence (17%) of immunofluorescence assay IgG anti-N. sennetsu antibodies compared with 4% and 0% from febrile patients (N = 848) in Thailand and Malaysia, respectively. We found N. sennetsu DNA by PCR, for the first time, in a fish (Anabas testudineus). These data suggest that sennetsu may be an under-recognized cause of fever and are consistent with the hypothesis that it may be contracted from eating raw fish.
    Matched MeSH terms: Food Microbiology
  15. A microdevice for rapid, monoplex and colorimetric detection of foodborne pathogens using a centrifugal microfluidic platform
    Sayad A, Ibrahim F, Mukim Uddin S, Cho J, Madou M, Thong KL
    Biosens Bioelectron, 2018 Feb 15;100:96-104.
    PMID: 28869845 DOI: 10.1016/j.bios.2017.08.060
    Outbreaks of foodborne diseases have become a global health concern; hence, many improvements and developments have been made to reduce the risk of food contamination. We developed a centrifugal microfluidic automatic wireless endpoint detection system integrated with loop mediated isothermal amplification (LAMP) for monoplex pathogen detection. Six identical sets were designed on the microfluidic compact disc (CD) to perform 30 genetic analyses of three different species of foodborne pathogens. The consecutive loading, mixing, and aliquoting of the LAMP primers/reagents and DNA sample solutions were accomplished using an optimized square-wave microchannel, metering chambers and revulsion per minute (RPM) control. We tested 24 strains of pathogenic bacteria (Escherichia coli, Salmonella spp and Vibrio cholerae), with 8 strains of each bacterium, and performed DNA amplification on the microfluidic CD for 60min. Then, the amplicons of the LAMP reaction were detected using the calcein colorimetric method and further analysed via the developed electronic system interfaced with Bluetooth wireless technology to transmit the results to a smartphone. The system showed a limit of detection (LOD) of 3 × 10-5ngμL-1 DNA by analysing the colour change when tested with chicken meat spiked with the three pathogenic bacteria. Since the entire process was performed in a fully automated way and was easy to use, our microdevice is suitable for point-of-care (POC) testing with high simplicity, providing affordability and accessibility even to poor, resource-limited settings.
    Matched MeSH terms: Food Microbiology
  16. Hemolytic and nonhemolytic vancomycin-resistant Enterococcus faecalis isolated from beef imported to Malaysia
    Fifadara N, Radu S, Hassan Z, Beuchat LR, Rusul G
    J Food Prot, 2003 Oct;66(10):1845-50.
    PMID: 14572222
    Twenty-two strains of vancomycin-resistant Enterococcus faecalis were isolated from 9 (6%) of 150 samples of frozen beef and beef products imported to Malaysia. The isolates were obtained from eight samples of beef and one sample of minced beef patty. No E. faecalis was isolated from frankfurters. Twelve of the 22 isolates (54.5%) were beta-hemolytic, and all isolates harbored the vanA gene. All vancomycin-resistant isolates were also resistant to streptomycin, erythromycin, kanamycin, bacitracin, ceftazimide, gentamycin, tetracycline, nalidixic acid, and teicoplanin; 95.4% were resistant to trimethoprimsulfamethoxazole; 68.8% were resistant to chloramphenicol; and 41% were resistant to ampicillin and penicillin. Small plasmids ranging in size from 1.5 to 5.8 kb were detected in 8 (36.4%) of 22 strains. The 22 isolates were classified into 20 random amplified polymorphic DNA types. Isolates were divided into two groups, each containing subclusters, that may reflect their clonal lineages. It is concluded that several clones of vancomycin-resistant E. faecalis are represented in the isolates obtained from beef imported to Malaysia.
    Matched MeSH terms: Food Microbiology
  17. Sonication reduces the attachment of Salmonella Typhimurium ATCC 14028 cells to bacterial cellulose-based plant cell wall models and cut plant material
    Tan MSF, Rahman S, Dykes GA
    Food Microbiol, 2017 Apr;62:62-67.
    PMID: 27889167 DOI: 10.1016/j.fm.2016.10.009
    This study investigated the removal of bacterial surface structures, particularly flagella, using sonication, and examined its effect on the attachment of Salmonella Typhimurium ATCC 14028 cells to plant cell walls. S. Typhimurium ATCC 14028 cells were subjected to sonication at 20 kHz to remove surface structures without affecting cell viability. Effective removal of flagella was determined by staining flagella of sonicated cells with Ryu's stain and enumerating the flagella remaining by direct microscopic counting. The attachment of sonicated S. Typhimurium cells to bacterial cellulose-based plant cell wall models and cut plant material (potato, apple, lettuce) was then evaluated. Varying concentrations of pectin and/or xyloglucan were used to produce a range of bacterial cellulose-based plant cell wall models. As compared to the non-sonicated controls, sonicated S. Typhimurium cells attached in significantly lower numbers (between 0.5 and 1.0 log CFU/cm2) to all surfaces except to the bacterial cellulose-only composite without pectin and xyloglucan. Since attachment of S. Typhimurium to the bacterial cellulose-only composite was not affected by sonication, this suggests that bacterial surface structures, particularly flagella, could have specific interactions with pectin and xyloglucan. This study indicates that sonication may have potential applications for reducing Salmonella attachment during the processing of fresh produce.
    Matched MeSH terms: Food Microbiology
  18. Effects of ultraviolet light (UV-C) and heat treatment on the quality of fresh-cut Chokanan mango and Josephine pineapple
    George DS, Razali Z, Santhirasegaram V, Somasundram C
    J Food Sci, 2015 Feb;80(2):S426-34.
    PMID: 25586772 DOI: 10.1111/1750-3841.12762
    The effects of ultraviolet (UV-C) and medium heat (70 °C) treatments on the quality of fresh-cut Chokanan mango and Josephine pineapple were investigated. Quality attributes included physicochemical properties (pH, titratable acidity, and total soluble solids), ascorbic acid content (vitamin C), antioxidant activity, as well as microbial inactivation. Consumers' acceptance was also investigated through sensory evaluation of the attributes (appearance, texture, aroma and taste). Furthermore, shelf-life study of samples stored at 4 ± 1 °C was conducted for 15 d. The fresh-cut fruits were exposed to UV-C for 0, 15, 30, and 60 min while heat treatments were carried out at 70 °C for 0, 5, 10 and 20 min. Both UV-C and medium heat treatments resulted in no significant changes to the physicochemical attributes of both fruits. The ascorbic acid content of UV-C treated fruits was unaffected; however, medium heat treatment resulted in deterioration of ascorbic acids in both fruits. The antioxidants were enhanced with UV-C treatment which could prove invaluable to consumers. Heat treatments on the other hand resulted in decreased antioxidant activities. Microbial count in both fruits was significantly reduced by both treatments. The shelf life of the fresh-cut fruits were also successfully extended to a maximum of 15 d following treatments. As for consumers' acceptance, UV-C treated fruits were the most accepted as compared to their heat-treated counterparts. The results obtained through this study support the use of UV-C treatment for better retention of quality, effective microbial inactivation and enhancement of health promoting compounds for the benefit of consumers.
    Matched MeSH terms: Food Microbiology
  19. Synthesis of a novel acrylated abietic acid-g-bacterial cellulose hydrogel by gamma irradiation
    Abeer MM, Amin MC, Lazim AM, Pandey M, Martin C
    Carbohydr Polym, 2014 Sep 22;110:505-12.
    PMID: 24906785 DOI: 10.1016/j.carbpol.2014.04.052
    Acrylated abietic acid (acrylated AbA) and acrylated abietic acid-grafted bacterial cellulose pH sensitive hydrogel (acrylated AbA-g-BC) were prepared by a one-pot synthesis. The successful dimerization of acrylic acid (AA) and abietic acid (AbA) and grafting of the dimer onto bacterial cellulose (BC) was confirmed by 13C solid state NMR as well as FT-IR. X-ray diffraction analysis showed characteristic peaks for AbA and BC; further, there was no effect of increasing amorphous AA content on the overall crystallinity of the hydrogel. Differential scanning calorimetry revealed a glass transition temperature of 80°C. Gel fraction and swelling studies gave insight into the features of the hydrogel, suggesting that it was suitable for future applications such as drug delivery. Scanning electron microscopy observations showed an interesting interpenetrating network within the walls of hydrogel samples with the lowest levels of AA and gamma radiation doses. Cell viability test revealed that the synthesized hydrogel is safe for future use in biomedical applications.
    Matched MeSH terms: Food Microbiology
  20. Attachment of bacterial pathogens to a bacterial cellulose-derived plant cell wall model: a proof of concept
    Tan MS, Wang Y, Dykes GA
    Foodborne Pathog Dis, 2013 Nov;10(11):992-4.
    PMID: 23941519 DOI: 10.1089/fpd.2013.1536
    This study aimed to establish, as a proof of concept, whether bacterial cellulose (BC)-derived plant cell wall models could be used to investigate foodborne bacterial pathogen attachment. Attachment of two strains each of Salmonella enterica and Listeria monocytogenes to four BC-derived plant cell wall models (namely, BC, BC-pectin [BCP], BC-xyloglucan [BCX], and BC-pectin-xyloglucan [BCPX]) was investigated. Chemical analysis indicated that the BCPX composite (31% cellulose, 45.6% pectin, 23.4% xyloglucan) had a composition typical of plant cell walls. The Salmonella strains attached in significantly (p<0.05) higher numbers (~6 log colony-forming units [CFU]/cm(2)) to the composites than the Listeria strains (~5 log CFU/cm(2)). Strain-specific differences were also apparent with one Salmonella strain, for example, attaching in significantly (p<0.05) higher numbers to the BCX composite than to the other composites. This study highlights the potential usefulness of these composites to understand attachment of foodborne bacteria to fresh produce.
    Matched MeSH terms: Food Microbiology
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