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151.
《Food Control》2016
Zearalenone (ZEA) contamination in food samples plays a critical role in food safety, since it causes serious health problems. Usage of microorganisms, such as lactic acid bacteria (LAB), is a promising new approach for detoxification. Eight Lactobacillus pentosus strains were evaluated for their ability to remove ZEA from a sodium acetate buffer solution with initial ZEA concentrations of 5.51–74.70 μg/mL. The adsorption capacity increased with increasing ZEA concentrations. The strain JM0812 showed the highest adsorption capability, at 83.17%, in solution containing 74.70 μg/mL ZEA, followed by UM054 (82.78%) and UM055 (81.69%), respectively. Three adsorption isotherms were applied to predict the removal efficiency of ZEA and the Freundlich isotherm appeared to have the best-fit for ZEA sorption onto bacterial cells. Our results indicate that Lb. pentosus strains are novel promising strains to reduce mycotoxin contamination in food products. 相似文献
152.
153.
Doron Steinberg 《Israel journal of chemistry》2016,56(5):273-281
Dental biofilms are composed of hundreds of bacterial species. These biofilms are diverse biological structures due to the heterogeneity of the many different types of supports in the oral cavity. The bacteria immobilized in these biofilms are exposed to rapid environmental changes such as pH, temperature, nutrition and anti-plaque agents. One mode in which these bacteria adapt in the dental biofilm is by quorum sensing. This cell-cell communication regulates diverse sets of adhesion modes, physiological changes, virulence properties, allowing the bacteria to persist in the dental biofilm under rapid environmental changes. In this review, we will concentrate mostly on the cariogenic bacterium Streptococcus mutans as one of the pivotal microorganisms in the supra-gingival biofilm that plays a major role in dental caries. 相似文献
154.
《Food Control》2014
Forty-two mahi-mahi fillets and 17 dried products sold in retail markets in Taiwan were tested for histamine and histamine-forming bacteria. The levels of pH, salt content, water content, Aw, TVBN, APC, TC and Escherichia coli in mahi-mahi fillet samples ranged from 5.6 to 6.5, 0.05 to 2.44%, 70.9 to 82.8%, 0.95 to 0.99, 5.9 to 23.5 mg/100 g, 3.1 to 7.0 log CFU/g, <3 to 1650 MPN/g and <3 to 45 MPN/g, respectively. The levels of pH, salt content, water content, Aw, TVBN, APC, TC and E. coli in dried mahi-mahi samples ranged from 5.7 to 6.4, 0.63 to 20.13%, 7.1 to 42.9%, 0.51 to 0.85, 21.4 to 133.9 mg/100 g, 3.6 to 8.7 log CFU/g, <3 to 5900 MPN/g and <3 to 2500 MPN/g, respectively. The average content of various biogenic amines in fillets samples was less than 0.3 mg/100 g. Four of the 17 dried samples (23.4%) had histamine levels greater than the FDA guideline of 5 mg/100 g for scombroid fish and/or product with one of them containing 68.15 mg/100 g of histamine, which is greater than the 50 mg/100 g hazard action level. Eight histamine-producing bacterial isolates, capable of producing 12.6 ppm–562 ppm of histamine in trypticase soy broth supplemented with 1.0% l-histidine (TSBH), were identified as Raoultella ornithinolytica (three isolates), Pantoea agglomerans (two isolates), Proteus vulgaris (two isolates) and Enterobacter amnigenus (one isolate), by 16S rDNA sequencing with PCR amplification. 相似文献
155.
Anna Rzepkowska Aleksandra Ołdak Danuta Kołożyn-Krajewska 《International Journal of Food Properties》2017,20(11):2736-2747
Twenty-one strains of the genus Lactobacillus and the genus Pediococcus, isolated from Polish raw fermented meat products, were examined for the potential probiotic properties: resistance to simulated gastric and intestine conditions, safety assessment, and antimicrobial properties. Strains were resistant to gastric enzymes and low pH (3–6 log CFU/mL decrease) and intestinal enzymes and bile salts (1–3 log CFU/mL decrease). Most strains were resistant to gentamycin, streptomycin, vancomycin, tetracycline, ciprofloxacin, and kanamycin. Three of them (Lb. brevis BAL1, BAL10, and KL5) produced β-glucuronidase, which excludes them from qualifying as safe. Seven strains had the ability to produce bacteriocins or bacteriocin-like substances. Overall, strains Lb. brevis SCH6, Pd. pentosaceus BAL6, and KL14 revealed selected superior characteristics (resistance to the gastrointestinal conditions, safety assessment, and antimicrobial properties) as compared to the other LAB strains investigated, which made them a viable bioprotective culture that can be inoculated in raw fermented meat products as starter cultures. 相似文献
156.
Tong Zhang Qing‐Mei Yan Lin Ye 《Journal of chemical technology and biotechnology (Oxford, Oxfordshire : 1986)》2010,85(10):1340-1345
BACKGROUND: This study was conducted to investigate the feasibility and performance of nitrogen removal through the complete autotrophic nitrogen removal over nitrite (CANON) process for saline wastewater in a continuous reactor, and to characterize microorganisms in the sludge from the reactor using DNA‐based techniques. RESULTS: The nitrogen removal experiment in the reactor was operated over five phases for 286 days treating a synthetic sewage of 1.2% salinity at 21–25 °C. At dissolved oxygen (DO) concentrations of 0.5–1.0 mg L?1 and in the presence of glucose, NO2? was accumulated, indicating the activity of ammonia‐oxidizing bacteria (AOB). At DO concentration of 0.5 mg L?1 without organic substrate, the anaerobic ammonium oxidation (Anammox) process was the major pathway responsible for nitrogen removal, with a total nitrogen removal of 70% and an ammonium conversion efficiency of 96%. A maximum ammonium removal rate of 0.57 kg‐N m?3 d?1 was achieved during the experimental period. The concentrations of AOB and Anammox bacteria were monitored over the operation of reactor using quantitative real‐time polymerase chain reaction (qRT‐PCR). CONCLUSION: In this study, autotrophic nitrogen removal process was achieved under salinity condition in a one‐reactor system. An over 100 fold increase of AOB was found due to the increased supply of ammonium at the beginning, then AOB concentration decreased temporarily in correspondence with the decreased DO, and the AOB resumed their concentration at the last phase. The Anammox bacteria abundance was about 150 fold higher than that at the beginning, indicating the successful enrichment of Anammox bacteria in the reactor. Copyright © 2010 Society of Chemical Industry 相似文献
157.
Ann‐Kathrin Kniggendorf Tobias William Gaul Merve Meinhardt‐Wollweber 《Microscopy research and technique》2011,74(2):177-183
Resonance Raman microscopy is well suited to examine living bacterial samples without further preparation. Therefore, comparatively little thought has been given to its compatibility with common fixation methods. However, fixation of cell samples is a very important tool in the microbiological sciences, allowing the preservation of samples in a specific condition for further examination, future measurements, transport, or later reference. We examined the effects of three common fixatives—ethanol, formaldehyde solution, and gentle heat—on the resonant Raman spectrum of three generic bacteria species, Rhodobacter sphaeroides DSM 158T, Rhodopseudomonas palustris DSM 123T, and Rhodospirillum rubrum DSM 467T, holding carotenoid‐ and heme‐chromophores in confocal Raman microscopy. In addition, we analyzed the effect of poly‐L ‐lysine coating of microscope slides, widely used for mounting biological and medical samples, on subsequent confocal Raman measurements of native and fixed samples. The results indicate that ethanol is preferable to formaldehyde as fixative if applied for less than 24 h, whereas heat fixation has a strong, detrimental effect on the resonant Raman spectrum of bacteria. Formaldehyde fixation excels at fixation times above 24 h, but causes an overall reduction in signal intensity. Poly‐L ‐lysine coating has no discernable effect on the Raman spectra of samples fixed with ethanol or heat, but it further decreases the signal intensity, especially at higher wavenumbers, in the spectra of samples fixed with formaldehyde. Microsc. Res. Tech. 74:177–183, 2011. © 2010 Wiley‐Liss, Inc. 相似文献
158.
BackgroundFunctional foods are a fastest growing sector of the food industry. The development of functional foods comprising omega-3 fatty acids and probiotic bacteria, through complex coacervation process is an emerging area of research and product development.Scope and approachWe reviewed relevant literature concerning the use of complex coacervation in microencapsulation, focusing primarily on the inclusion of probiotic bacteria and omega-3 oils into a single delivery format. This review covers advantages and disadvantages of the complex coacervation process to microencapsulate bioactive ingredients, viability of probiotic bacteria and oxidative stability of omega-3 oil during the complex coacervation process, the bioaccessibility of omega-3 oil and probiotic bacteria during simulated gastrointestinal conditions and in-vivo testings.Key findings and conclusionsThe review describes the advantages of co-encapsulation using complex coacervation followed by spray drying. It also describes the technological hurdles that need to be resolved for further development of industrial applications of co-encapsulation of probiotic bacteria and omega-3 lipids. The co-encapsulation concept has been widely used in pharmaceutical delivery systems, but is a relatively new concept in food ingredient stabilisation and delivery. There is a commercial need of co-encapsulation of multiple bioactive ingredients within a single microcapsules, due to decreased cost and enhanced product quality. Complex coacervation has been shown to be a useful method for the co-encapsulation of multiple unstable bioactive ingredients. Although in-vitro evaluation deliver useful bioavailability information, additional in-vivo and clinical trials are needed to determine the efficacy of bioactive release, particularly for microcapsules containing multiple bioactive ingredients. 相似文献
159.
Parichat Phankhamla Jutaporn Sawaengkaew Panhathai Buasri Polson Mahakhan 《International Journal of Hydrogen Energy》2014
Thirty-nine purple non-sulfur bacteria (PNSB) were isolated from 162 environmental samples. These isolates of PNSB were tested for their ability to produce biohydrogen (Bio-H2) at 40 °C and only 14 isolates were noted to possess such ability, which were considered as thermotolerant photosynthetic Bio-H2 producing bacteria (tt-PHPB). Of 14 isolates of tt-PHPB, KKU-SN1/1 was observed to have the highest Bio-H2 productivity. Central composite design was employed to optimize the operating conditions for maximal Bio-H2 production by the strain KKU-SN1/1. Under optimal conditions (7.6 g/L malic acid, 11 g/L glutamic acid, pH 6.7, at 40 °C) the Bio-H2 production was increased by 68.28%. The purity of Bio-H2 produced was 92.22%, as suggested by gas chromatography (GC-TCD). Based on morphological characteristics and 16S rDNA sequence analysis, the strain KKU-SN1/1 was identified as Rhodopseudomonas pentothenatexigens, with 99.7% similarity. To our knowledge, this is the first report on Bio-H2 production by R. pentothenatexigens KKU-SN1/1. 相似文献
160.
《Food Control》2017
A total of 230 isolates of lactic acid bacteria were isolated from gastrointestinal tracts (GIT) of indigenous chickens purchased from local market in Bang Rakam district, Phitsanulok, Thailand. Among 230 isolates, only 7 isolates, named CM6CR07, CM6CR11, CF1GI15, CF1GI14, CF1GI17-1, CF1GI17-2 and CF1GI 19 showed an inhibition zone against indicator strains. Bacteriocin activity was completely inactivated when Neutralized Cell Free Supernatants (NCFS) of the isolates were treated with proteases, confirming the proteinaceous nature of the bacteriocin component. NCFS of all selected bacteriocin producing lactic acid bacteria (SBP-LAB) retained their bacteriocin activity after heating at 100 °C for 30 min. All of SBP-LAB were identified as Enterococcus faecalis. These Ent. faecalis isolates harbored the same virulence genes. All strains were positive for gelE (gelatinase), efaAfs (cell wall adhesins), hyl (hyaluronidase), ace (adhesin of collagen protein), cylLL (cytolysin structural subunit) and cylLS (cytolysin structural subunit) and were negative for asa1 (aggregation substance), agg (aggregation protein involved in adherence to eukaryotic cells), and esp (enterococcal surface protein). These Ent. faecalis showed a wide range of inhibitory spectrum against food-spoilage and food-borne pathogens when studied by agar spot test. The CFS and NCFS also inhibited some of food-spoilage and food-borne pathogenic indicator strains when checked by agar well diffusion assay. All of these Ent. faecalis survived simulated stomach conditions, whereas all of them could survive in conditions of simulated intestinal juice. 相似文献