Characterization of Bacillus Cereus Isolated From Readyto-Eat Cereals

Since availability of data on the contamination of spore formers such as B. cereus in ready-to-eat foods is scarce particularly from developing countries, this surveillance was conducted to address the issue. The preliminary findings from this study revealed a high prevalence of B. cereus s.l. being detected using MPN-PCR in 76% of 111 samples of ready-to-eat cereals tested. The range of concentration was from 30 MPN/g to more than 24,000 MPN/g. Results indicated the differences in the level of contamination for B. cereus s.l. in various products based on factors such as product types, ingredients added and location of manufacturer. The highest concentration of B. cereus s.l. was found in samples with ingredients from weaning products which are, product made from vegetable origin. The alarming findings on the high prevalence of B. cereus s.l. in ready-to-eat cereals prompted further studies on the isolates from these samples. Isolation of colonies from these samples were characterized based on toxin gene screening, plasmid profiles, antibiotic resistance and fingerprinted using RAPD-PCR analysis. In addition to the high prevalence in RTE cereals, the toxin screening profile indicated 58% of the isolate carry the Bacillus enterotoxin T (bceT gene) and 34% carries the tri-component non-hemolytic enterotoxin (nhe gene). This shows that majority of the isolates from ready-toeat cereals are diarrheagenic. The plasmid profile revealed one isolate carrying the plasmid size similar to cereulide protein which is responsible for the emetic disease therefore showing the less common prevalence of emetic isolates from RTE cereals. Isolates of B. cereus s.l. were found to be resistant to ampicillin, metronidazole but highly susceptible to antibiotics with mechanism of action that inhibits the protein synthesis such as erythromycin, oxytetracycline, spectinomycin, neomycin, furozolidone, quinopristin/dalfopristin. Even though B. cereus usually manifests a self limiting disease, the emergence of antibiotic resistance bacteria is a major concern worldwide and due to ease of horizontal gene transfer between the subspecies of B. cereus s.l., the risk of other more lethal subspecies such as B. anthracis obtaining the antibiotic resistance gene may also occur. This preliminary finding revealed an interesting risk profile for B. cereus s.l. as there are no known data available for the assessment on the microbiological quality of RTE cereals especially for spore formers. Based on the risk assessment study conducted, an estimate of on worst case scenario showed 48 diarrhea cases in 27 million populations are known to occur per annum from consumption of RTE cereals

The "non-regularizability" of gapless free fermion Hamiltonian protected by on-site symmetries

The non-regularizability of free fermion field theories, which is the root of various quantum anomalies, plays a central role in particle physics and modern condensed matter physics. In this paper, we generalize the Nielsen-Ninomiya theorem to all minimal nodal free fermion field theories protected by the time reversal, charge conservation, and charge conjugation symmetries. We prove that these massless field theories cannot be regularized on a lattice.Comment: 29 pages, 4 figure

Characterization of fungi from palm kernel cake (PKC) and the effect of storage temperature on fungi growth

The widespread contamination of animal feed with mycotoxin is not a new issue worldwide. Apart from economic loss, mycotoxin can have adverse health effects on humans due to the carcinogenicity, teratogenicity and mutagenicity potential of the toxins. Palm kernel cake (PKC) is the largest animal feed production in Malaysia. PKC is a by-product of palm kernel oil processing and it has been exported as animal feed. The purpose of this study was to isolate and characterise toxigenic fungi cultured in three different media, Dichloran Rose Bengal Chloramphenicol (DRBC) Agar, Dichloran 18% Glycerol (DG18) Agar and Malt Extract Agar (MEA), derived from PKC that is stored under three different temperatures, 4°C, 25°C and 60°C. Identification of fungi was carried out based on macroscopy and microscopy as well as molecular identification. Four mycotoxigenic fungi were found: Aspergillus niger, Aspergillus flavus, Aspergillus fumigatus and Penicilium citrinum. In order to characterise polymorphism of the isolates, RAPD assay was performed using OPA 3 as the primer. The software resulted in a constructed dendrogram that revealed the percentage of similarities between the typable isolates (A. fumigatus, A. niger and P. citrinum) within range from 20% to 80%. The effect of storage temperature on the strains' enumeration is reported in this work. The distributing strains are influenced by the storage temperature of the PKC matrices. The findings clearly show that Aspergillus species profused at 25°C PKC storage, while it was restricted at low and high temperature

A Holographic Theory for the Phase Transitions Between Fermionic Symmetry-protected Topological States

In an earlier work we developed a holographic theory for the phase transition between bosonic symmetry-protected topological (SPT) states. This paper is a continuation of it. Here we present the holographic theory for fermionic SPT phase transitions. We show that in any dimension $d$, the critical states of fermionic SPT phase transitions has an emergent $Z_2^T$ symmetry and can be realized on the boundary of a $d+1$-dimensional bulk SPT with an extra $Z_2^T$ symmetry.Comment: 35 pages, 10 figure

Characterization of Enterobacter cloacae isolated from street foods

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

Hand hygiene knowledge, attitudes and practices among food handlers at primary schools in Hulu Langat district, Selangor (Malaysia)

The purpose of this study was to investigate the hand hygiene knowledge, attitudes and practices of food handlers from 38 primary schools in Hulu Langat district, Selangor State in Malaysia. Hand hygiene knowledge, principally regarding ready-to-eat foods, the existence of bacteria and correct hand-washing methods were lacking among the food handlers. From the observations reported herein, the use of masks and hand-washing with proper technique were neglected by most food handlers. In the demographic profile analysed, there were significant differences (p ≤ 0.05) in the following areas: hand-washing practices between genders (p = 0.039), hand hygiene attitudes and glove use between nationalities (p = 0.002 and p = 0.029, respectively); and personal hygiene knowledge between groups with different levels of education (p = 0.048). This study revealed a slightly positive relationship between hand hygiene knowledge and self-reported practices of food handlers (r = 0.249, p = 0.022). The results showed that further continuous effort should be invested in hand hygiene education and enforcement for food handlers from primary schools in the Hulu Langat district. This study provided data about the current knowledge, attitudes and practices of food handlers from institutional foodservice operations in Malaysia regarding hand hygiene

Effects of natto extract on endothelial injury in a rat model

Vascular endothelial damage has been found to be associated with thrombus formation, which is considered to be a risk factor for cardiovascular disease. A diet of natto leads to a low prevalence of cardiovascular disease. The aim of the present study was to investigate the effects of natto extract on vascular endothelia damage with exposure to laser irradiation. Endothelial damage both in vitro and in vivo was induced by irradiation of rose bengal using a DPSS green laser. Cell viability was determined by MTS assay, and the intimal thickening was verified by a histological approach. The antioxidant content of natto extract was determined for the free radical scavenging activity. Endothelial cells were injured in the presence of rose bengal irradiated in a dose-dependent manner. Natto extract exhibits high levels of antioxidant activity compared with purified natto kinase. Apoptosis of laser-injured endothelial cells was significantly reduced in the presence of natto extract. Both the natto extract and natto kinase suppressed intimal thickening in rats with endothelial injury. The present findings suggest that natto extract suppresses vessel thickening as a synergic effect attributed to its antioxidant and anti-apoptosis properties

Antimicrobial resistance of Escherichia coli and Staphylococcus aureus isolated from food handler's hands

The aim of this study was to determine the antimicrobial resistance of Escherichia coli and Staphylococcus aureus isolates from food handlers' hands at primary schools in Hulu Langat district, Selangor (Malaysia). Disc diffusion methods were used to examine the antimicrobial resistance of the bacteria by using ten types of antibiotic discs with different concentrations. The results show that the prevalence of S. aureus (65.88–74.12%) was far higher than the prevalence of E. coli (9.41–14.12%). The percentage isolates of E. coli that were resistant to the antibiotics was 85.71% Penicillin and Chloramphenicol, 57.14% Sulfamethoxazole-Trimethoprim, Ampicillin and Trimethoprim, 28.57% Kanamycin and Tetracycline and 14.29% Ciprofloxacin. All of the isolates had shown susceptible to Gentamicin and Nitrofurantoin. For S. aureus, the percentage isolates that were resistant to the antibiotics was 72.30% Ampicillin, 53.38% Penicillin, 4.73% Nitrofurantoin,1.35% Chloramphenicol and Trimethoprim and 0.68% Kanamycin and Tetracycline. None of the isolates had shown resistant to Ciprofloxacin, Sulfamethoxazole-Trimethoprim and Gentamicin. Multidrug resistant Escherichia coli represented a high percentage (85.71%) of the total positive strains revived whereas multidrug resistant S. aureus strains were only 5.41% of the total positive strains. The existence of multidrug resistant bacteria is quite worrying as they may pose serious threat to the patients. Hence, the microbiological quality of food handlers' hands from foodservice operations should be maintained in a good condition to reduce the existence of multidrug resistance bacteria

In vitro antibacterial activity of marine-derived fungi isolated from Pulau Redang and Pulau Payar Marine Parks, Malaysia against selected food-borne pathogens

Marine fungi are potential source of bioactive compounds as indicated by the increasing statistic of research findings. However similar research in Malaysia is still lacking. Hence, this study is undertaken to determine the antibacterial activity of four marine fungal isolates (PR1T4, PP2L4, PR3T13 and PR5T4) from Pulau Redang and Pulau Payar Marine Parks, Malaysia against Salmonella Typhi, Listeria monocytogenes, Staphylococcus aureus, and Escherichia coli. Fungal isolates were first macroscopically and microscopically characterized and later molecularly identified as Penicillium citrinum, Sacroladium strictum, Aspergillus sydowii and Aspergillus sp. respectively. Solid and broth fermentation of fungi were carried out to produce crude extracts and these extracts were screened for antibacterial activity. In general, solid fermentation extracts (SFE) showed significantly higher antibacterial activity (p < 0.05) against all four pathogens compared to broth fermentation extracts (BFE) as the largest inhibitory activity of SFE and BFE was (32.17±0.67 mm) and (27.57±0.81 mm) respectively both on S. aureus by S. strictum. Highest antibacterial activity against L. monocytogenes (27.95±0.81 mm) was exhibited by SFE of A. sydowii while SFE of S. strictum showed highest activity against S. aureus (32.17±0.67 mm) and E. coli (23.53±0.57 mm) and SFE of Aspergillus sp. showed largest inhibition towards S. Typhi (29.30±0.33 mm). These prominent results suggest that all four isolates have potential to be explored as new source of antibacterial agents against food-borne pathogens