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E Gerasi E Litopoulou-Tzanetaki N Tzanetakis 《International Journal of Dairy Technology》2003,56(2):117-122
Changes in the microbial flora of Manura, a raw ovine milk cheese, were studied during ripening. In general, the various microbial groups developed better on the cheese surface than in the interior, but red wine treatment had an inhibitory effect on their growth and microbial counts decreased ( P < 0.05) more rapidly on the cheese surface than in the interior. NaCl and moisture of the cheese affected microbial levels significantly. Thus, Enterobacteriaceae and coliforms were reduced sharply ( P < 0.05) during ripening on a straw bed (∼3 months) and they were not detected in mature cheese. Lactic acid bacteria predominated over the other microbial groups throughout ripening. Leuconostoc mesenteroides ssp. cremoris , Pediococcus pentosaceus and Lactobacillus paracasei ssp. paracasei , frequently found in maturing cheese, could be used as starters to make this cheese. Moreover, the lactic acid bacteria predominating in mature cheese, such as Weissella paramesenteroides , Lactobacillus bifermentans and Lactobacillus brevis , may contribute to cheese ripening through their biochemical activities. 相似文献
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M. Cruz-Romero A.L. Kelly J.P. Kerry 《Innovative Food Science and Emerging Technologies》2008,9(4):441-447
The microbiological quality of oysters high-pressure (HP)-treated in-shell at 260 MPa for 3 min, or 500 or 800 MPa for 5 min and then stored at 2 °C, were investigated. Microbial counts after HP treatment showed that the bacterial load was reduced after treatment at all pressures to levels below the detection limit. Randomly-selected isolates from the total aerobic viable counts of untreated and HP-treated oysters after 14 days of storage were identified by the API identification system. Bacteria isolated from oysters HP-treated at 260 MPa were Shewanella putrifaciens and Pseudomonas fluorescens. For oysters HP-treated at 500 or 800 MPa, the main bacteria isolated were Pseudomonas spp. Vibrio spp. comprised 44% of the microflora in untreated oysters after storage for 14 days at 2 °C, but no Vibrio were detected in HP-treated oysters. This study confirmed that HP processing can inactivate microorganisms and delay microbial growth in chilled stored oysters.
Industrial relevance
High-pressure (HP) treatment is being increasingly employed for commercial processing of oysters but no studies of the microflora of HP-treated in-shell oysters have been reported. HP treatment significantly changed the microflora of oysters and apparently has good potential for inactivation of Vibrio spp as HP treatment, in combination with adequate chilled storage, can improve the microbiological shelf-life and safety of oysters. 相似文献3.
Ian D. Fisk Konstantinos Gkatzionis Mita Lad Christine E. R. Dodd David A. Gray 《European Food Research and Technology》2009,228(4):613-621
The effect of irradiation (0–20 kGy) on hemp and sunflower seeds was assessed, with specific reference to the oxidatively
labile lipid component (unsaturated fatty acids and tocochromanols). Total protein, lipid, and solids content of the seeds
did not vary with irradiation dose. Lipid hydroperoxide concentration increased significantly in the sunflower seeds (48 mmol kg−1 lipid) and a significant increase in volatile secondary oxidation products was measured in both seeds (e.g. hexanal, heptanal,
1-penten-3-ol) with increasing irradiation dose. Irradiation at 5 kGy sterilised the seeds of all microbial contamination
and irradiation doses of 20 kGy prevented germination. A loss of the antioxidant tocopherol was shown with increasing irradiation
doses, although this was selective for specific tocopherol isoforms (α-tocopherol, β-tocopherol and γ-tocopherol). 相似文献
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真空包装冷却猪肉低剂量辐照后的微生物菌落特性变化 总被引:7,自引:0,他引:7
研究了真空包装的冷却猪肉未经保鲜液处理或经保鲜液处理,分别经0、0.5、1、2kGy剂量辐照后,其在冷藏过程中的细菌总数、乳酸细菌、肠杆菌科以及假单胞菌属的变化。实验结果表明:(1)初始菌数对数值为5.15的冷却猪肉,经0.5kGy和1kGy辐射(辐射温度为30~32℃)后,除对肠杆菌科茵有明显抑菌作用外,对细菌总数、乳酸细菌、假单胞菌属均无抑菌作用。(2)而在同样处理条件下,2kGy辐射剂量就可以明显抑制细菌总数、乳酸细菌、肠杆菌科、假单胞菌属,特别是肠杆菌科在贮存末期其对数值可降到2~3的范围。(3)最佳的处理条件为:保鲜液处理 真空包装 2kGy剂量辐照 冷藏[(3±1)℃]。这几方面结合可以最大程度地延长冷却猪肉的货架期。 相似文献
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Soy isoflavonoids have many useful properties. However, they are metabolized in vivo, including in humans. The effect of the metabolism of soy isoflavonoids on their properties is not fully understood. We have isolated the bacterial strain SY8519, which has been shown to metabolize daidzein to O-desmethylangolensin and to produce 2-(4-hydroxyphenyl)propionic acid from genistein. According to chiral HPLC analysis, the 2-(4-hydroxyphenyl)propionic acid obtained from the bacterium was optically active. To determine the absolute stereochemistry of the microbial product, we prepared (S)-2-(4-hydroxyphenyl)propionic acid from (S)-2-phenylpropionic and concluded that the microbial product had an R-configuration by chiral HPLC analysis. We also applied the metabolite to mouse adipocytes and found that 2-HPPA was less effective at reducing leptin secretion than the parent compound genistein. Our results suggested that ‘O-desmethylangolensin-production’ attenuates the effect of soy isoflavonoids by reducing not only the activity of daidzein but also that of genistein. 相似文献
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A. Fabiani M. Castaldini C. Musso G. Berta 《The Science of the total environment》2009,407(17):4954-4964
The use of microorganisms as bioindicators of soil health is quite a new feature, rarely considered for the soil health evaluation in chronically-polluted industrial sites, and still suffering of the bias related to the technique applied.In this work we applied a microbiological polyphasic approach, relying on soil indigenous microorganisms as bioindicators and combining culture-dependent and -independent methods, in order to evaluate soil health of four sites (1a, 1b, 2a and 2b) inside a chemical factory with a centenary activity. Functional as well as structural aspects were comprehensively considered. Results were related to the kind of pollutants found in each site.Heavy metal pollution was recorded in sites 1b and 2b, while both organic and inorganic substances were detected in sites 1a and 2a. Based on the chemical and physical properties of the four soils, site 1b and 2b grouped together, while 1a and 2a were separated from the others.The density of the culturable bacteria was very low in site 2a, where only Gram-positive were found. According to the identification of culturable bacteria, site 2a showed the lowest similarity with the other sites. Microbial activity was detected only in sites 1b and 2b. PCR-DGGE (Denaturing Gradient Gel Electrophoresis), was performed on the culturable, total and active microbial communities. Consistently with the identification of culturable bacterial strains, the molecular profile of the culturable fraction of site 2a, was clearly separated from the molecular profiles of other sites in cluster analysis. Molecular fingerprintings of the whole and active bacterial communities differed among the sites, but clustered according to the pollutants present in each site. The presence of possible key species in each site has been discussed according to the whole and active species.Since the results obtained by microbiological analysis are consistent with the chemical data, we suggest that the use of this microbiological polyphasic approach and of microorganisms as intrinsic bioindicators, can be suitable for the evaluation of soil health. 相似文献
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Zenghui Xu Liyun Zhang Yongtao Wang Xiufang Bi Roman BuckowXiaojun Liao 《Journal of food engineering》2011,104(4):577-584
The inactivation of microorganisms and enzymes of cloudy apple juice, and some physico-chemical properties of the juice were investigated after continuous high pressure carbon dioxide (HPCD) at 25 MPa and 43 °C, for 2 min and at 22 MPa and 60 °C for 3, 5 and 10 min, respectively. The coliform bacteria were completely inactivated in all the cases. Total aerobic bacteria was reduced by 3.72 log cycles, pectin methylesterase was reduced by 54.3% and polyphenol oxidase was completely inactivated after 10 min treatment at 22 MPa and 60 °C. The yeasts and molds were completely inactivated and the turbidity increased at 22 MPa and 60 °C regardless of time, while the L and a value reduced, but browning degree did not change. The particle size distributions of the juice changed after HPCD but were regained as treatment time was prolonged. The pH was reduced at 22 MPa and 60 °C for 3 or 5 min. 相似文献