Identification and antibiotic susceptibility of bacterial isolates from probiotic products

In the present study, a total of 55 European probiotic products were evaluated with regard to the identity and the antibiotic resistance of the bacterial isolates recovered from these products. Bacterial isolation from 30 dried food supplements and 25 dairy products, yielded a total of 268 bacterial isolates selected from several selective media. Counts of food supplements showed bacterial recovery in 19 (63%) of the dried food supplements ranging from 10(3) to 10(6) CFU/g, whereas all dairy products yielded growth in the range of 10(5)-10(9) CFU/ml. After identification of the isolates using whole-cell protein profiling, mislabeling was noted in 47% of the food supplements and 40% of the dairy products. In six food supplements, Enterococcus faecium was isolated whereas only two of those products claim this species on their label. Using the disc diffusion method, antibiotic resistance among 187 isolates was detected against kanamycin (79% of the isolates), vancomycin (65%), tetracycline (26%), penicillinG (23%), erythromycin (16%) and chloramphenicol (11%). Overall, 68.4% of the isolates showed resistance against multiple antibiotics including intrinsic resistances. Initially, 38% of the isolated enterococci was classified as vancomycin resistant using the disc diffusion method, whereas additional broth dilution and PCR assays clearly showed that all E. faecium isolates were in fact vancomycin susceptible.     

Assessing the ecotoxicity of pesticide transformation products

Once released to the environment, pesticides may be degraded by abiotic and biotic processes. While parent compounds are assessed in detail in many regulatory schemes, the requirements for the assessment of transformation products are less well developed. This study was therefore performed to explore the relationships between the toxicity of transformation products and their parent compounds and to develop a pragmatic approach for use in the risk assessment of transformation products. Data were obtained on the properties and ecotoxicity of transformation products arising from a wide range of pesticides. Generally, transformation products were less toxic to fish, daphnids, and algae than their parent compound. In instances where a product was more toxic, the increase in toxicity could be explained by either (1) the presence of a pesticide toxicophore; (2) the fact that the product is the active part of a propesticide; (3) the product is accumulated to a greater extent than the parent compound; or (4) the product has a more potent mode of action than the parent. On the basis of the findings, an approach has been proposed to estimate the ecotoxicity of transformation products based on chemical structure and data on the toxicity of the parent compound. The assessments can be performed at an early stage in the risk assessment process to identify those substances that require further testing.     

农产品质量安全从农业生产模式转变做起

农产品安全问题是广大消费者最为关注的话题,如何从监管、生产种植等方面提高农产品质量安全成为研究的热点。本文对当前监管系统进行优化,同时提供"自然农法"这一整套农业生产方法,禁止"化肥、农药、激素"等有毒有害物质的投入,通过研究病虫害发生根源,从源头解决问题,并使用生物、物理方法进行病虫害预防与防治,在生产成本不做大幅提高的同时,使安全农产品生产得以进行推广普及。     

Analyses of volatile transformation products from additives in gamma-irradiated polyethylene packaging

Thermal desorption, followed by gas chromatography (GC) with mass spectrometry (MS) detection, has been found to allow the rapid identification of volatile products resulting from the gamma-irradiation of stabilized, high density polyethylene packaging and pure stabilizers. The stabilizers were tris(2,4-di-tert.butylphenyl) phosphite, octadecyl beta-(2,6-di-tert.butylphenol)-propionate and 2,4-di-tert.butylphenol, the latter resulting from phosphite hydrolysis. Thermal desorption indicated the formation and release of tert.butylbenzenes, such as 1,3-di-tert.butylbenzene upon gamma-irradiation of the HDPE. From a comparison of the products from gamma-irradiation of additive-free polyethylene, of various pure stabilizers and of related compounds, the tert.butylbenzenes were confirmed to result from the irradiation of the phosphite stabilizer and its phosphate conversion product. Thermal desorption off-line, in which volatiles released by a sample are trapped in sorbents for subsequent desorption in the heated GC inlet, is found to be a fast, extremely sensitive method that can be used to guide and supplement analyses of compounds extracted by foodstuffs.     

从营销的观念人手进行产品创新设计

阐述了在纺织新产品设计中即要打出高水平,又要兼顾企业利润、市场需求.同时指出,做一个合格的设计人员,即要会产品设计,也要懂质量、营销等多方面知识.文章提出了新产品设计的前期必须重视对市场和消费者的分析过程和制定一个切实可行的营销策略.     

Stability and transformation of products formed from dimeric dehydroascorbic acid at low pH

Dehydroascorbic acid dimer (DDHA) is the commercially available form of oxidised vitamin C. When DDHA enters an aqueous environment, it will interact with water, but the details of this process are not well defined. Hydration of DDHA was analyzed as a function of concentration, pH and temperature. Above pH 5 only hydrated dehydroascorbic acid monomer (DHA) and its degradation product 2,3-diketogulonic acid (DKG) were observed. At pH lower than 4 and in MilliQ water, relatively stable hydrated dimeric species were additionally detected. They are intermediates formed from DDHA and transformed into DKG, either directly or through DHA. A lower temperature of dissolution favours the formation of hydrated dimeric products, while the concentration of DDHA has no effect on their yield. All products were separated chromatographically and analyzed by three detectors: diode array, refractive index and electrospray ionisation mass spectrometry. The stability and transformations of products were studied in the mixture and in the isolated fractions. Two initially formed monohydrated products are transformed to a dihydrated product that is degraded to DHA and DKG. Once formed, the dihydrated product and one of the monohydrated products are sufficiently stable to be identified at neutral pH. All three hydrated products are interconvertible and can be also formed after dissolution of dried DHA.     

Resistance of bacterial isolates from poultry products to therapeutic veterinary antibiotics

Bacterial isolates from poultry products were tested for their susceptibility to 10 antibiotics commonly used in the therapeutic treatment of poultry. Bacteria were isolated from fresh whole broiler carcasses or from cut-up meat samples (breast with or without skin, wings, and thighs) that were either fresh or stored at 4 or 13 degrees C (temperatures relevant to poultry-processing facilities). The Biolog system was used to identify isolates, and a broth dilution method was used to determine the antibiotic resistance properties of both these isolates and complementary cultures from the American Type Culture Collection. The antibiotics to which the most resistance was noted were penicillin G, sulfadimethoxine, and erythromycin; the antibiotic to which the least resistance was noted was enrofloxacin. Individual isolates exhibited resistances to as many as six antibiotics, with the most common resistance pattern involving the resistance of gram-negative bacteria to penicillin G, sulfadimethoxine, and erythromycin. Differences in resistance patterns were noted among 18 gram-positive and 7 gram-negative bacteria, and comparisons were made between species within the same genus. The data obtained in this study provide a useful reference for the species and resistance properties of bacteria found on various raw poultry products, either fresh or stored at temperatures and for times relevant to commercial processing, storage, and distribution. The results of this study show that resistance to antibiotics used for the therapeutic treatment of poultry occurs in bacteria in the processing environment.     

Cluster analysis, richness and biodiversity indexes derived from denaturing gradient gel electrophoresis fingerprints of bacterial communities demonstrate that traditional maize fermentations are driven by the transformation process

The bacterial communities of maize fermented foods (pozol, poto-poto and ogi) from Mexico, Congo and Benin was compared using a culture-independent approach [denaturing gradient gel electrophoresis (DGGE) analysis of total DNA]. Foods produced following the same flow chart (i) grouped in distinct clusters, (ii) shared similar richness and biodiversity indexes and (iii) exhibited a high intra-specific variability. Structural biodiversity was higher in pozol samples, probably due to oxic conditions and higher initial pH. DGGE bands found in foods of different origins suggest that Lactobacillus plantarum, Lb. delbrueckii and Lb. fermentum are particularly well adapted to the fermentation of maize.     

熟制凡纳滨对虾优势腐败细茵的分离鉴定及抑茵剂的筛选

筛选出适用于熟制凡纳滨对虾的生物抑菌剂,以期延长熟制凡纳滨对虾的货架期。对熟制凡纳滨对虾中优势腐败细菌进行分离鉴定,采用牛津杯法研究不同浓度壳聚糖、乳酸链球菌素(Nisin)和溶菌酶对分离到的优势腐败细菌的抑菌效果。结果表明,从熟制凡纳滨对虾中分离到的2株优势腐败细菌,一株属于芽孢杆菌属,一株是白色海球菌;壳聚糖对2株优势腐败细菌均有抑菌作用,抑菌效果随着壳聚糖浓度的增大而增强,2株优势腐败细菌对浓度为15.0mg/100mL的壳聚糖高度敏感。Nisin和溶菌酶对2株优势腐败细菌无抑菌作用。     

深圳市面粉与面制品中偶氮甲酰胺及其转化产物膳食暴露评估

目的了解深圳市居民面粉与面制品中偶氮甲酰胺及其分解转化产物联二脲、氨基脲的含量水平,获得深圳市致癌致畸物氨基脲的居民膳食暴露水平。方法 2016年在深圳市超市、批发市场、农贸市场等共采集500份面粉及面制品,监测偶氮甲酰胺及其分解转化产物联二脲、氨基脲的含量。并结合深圳市居民膳食调查食物消费量计算深圳市居民面粉和面制品中氨基脲的暴露量。结果所采集的500份样品中:偶氮甲酰胺、联二脲、氨基脲的检出率分别为4.60%、25.8%、18.6%,含量范围为0.500～93.4 mg/kg、10.0～13900μg/kg、0.250～1100μg/kg;氨基脲的一般水平暴露量与高水平暴露量分别为0.005μg/kg-bw/d与0.248μg/kg-bw/d。结论面粉及面制品中的氨基脲暴露已超过水产品中的暴露,应慎重使用偶氮甲酰胺作为食品添加剂在面粉及面制品中使用,同时加强对面粉及面制品中氨基脲的监测。     

Indicators for the exposure assessment of transformation products of organic micropollutants

Environmental transformation products of organic micropollutants have the potential to be similarly or even more mobile, persistent, ortoxic than their parent compounds. They should, therefore, be included in chemical hazard and risk assessment procedures as well as in the assessment of soil and water quality. To fulfill this requirement most efficiently, screening approaches that select relevant transformation products for detailed assessment are needed. This paper presents two process-based multimedia, multispecies models that allow us to quantitatively estimate the environmental fate of transformation products. The resulting exposure patterns are assessed with two indicators: joint persistence (JP), which describes the temporal extent of environmental exposure to a parent compound and its transformation products, and the predicted relative aquatic concentrations (RAC), which estimate the relative concentrations of parent compounds and their transformation products in surface water bodies. As a case study, JP and RAC are calculated for 16 pesticides and their relevant transformation products. The results for the JP indicator confirm the importance of considering transformation products in the assessment of overall persistence; for example, in the context of PBT assessments. Comparison of RAC results with monitoring data on herbicides and their transformation products shows the suitability of our approach for estimating relative concentrations in surface water, and as a consequence, its usefulness in identifying transformation products for future water quality monitoring programs. Transformation products of triketones and other highly used acidic herbicides are specifically identified as targets.     

2015~2018年玉溪市售肉及肉制品细菌性污染状况调查

目的 调查2015~2018年玉溪市售肉及肉制品的细菌性污染状况。方法 采用国家标准方法对161份2015~2018年玉溪市售肉及肉制品进行细菌总数、大肠埃希氏菌、致泻大肠埃希氏菌、金黄色葡萄球菌、沙门氏菌、单核细胞增生李斯特氏菌、空肠弯曲菌、小肠结肠炎耶尔森氏菌及产气荚膜梭菌检测分析。结果 本次调查的161件肉及肉制品中, 单核细胞增生李斯特氏菌、沙门氏菌、金黄色葡萄球菌和空肠弯曲菌的总检出率依次为2.91%、9.68%、7.14%和5.22%; 冷却肉类生肉制品的致病菌检出率最高(37.04%), 与其他肉类制品的检出率间有显著性差异(P<0.05); 同一细菌性污染物指标, 在不同季度的检出率差异均无统计学意义(P>0.05); 食源性致病菌中金黄色葡萄球菌超标率最高(28.57%); 城市肉类样品检出率略高于农村; 致病菌在流通环节的总检出率高于餐饮服务环节, 其差异均无统计学意义(P>0.05); 研究中的6种动物性肉类样品的细菌性污染状况不一, 其检出率间存在显著性差异(P＜0.05)。结论 2015~2018年玉溪市售肉类制品中细菌性污染较为严重, 应进一步加强相关产品的全过程监管。     

新型烟草制品市场发展及法律监管

在对近年来电子烟、加热烟草产品、鼻烟、嚼烟等新型烟草制品的国际国内市场发展和法律监管动态进行梳理分析的基础上,总结出当前新型烟草制品在市场发展和法律监管方面的变化趋势、主要特征,结合当前行业新型烟草制品发展现状,从行业、工业企业、商业企业、监管政策等方面提出针对性的策略建议。      

一种新型肉糜类调理禽肉制品的研制

TG酶是一种新型的酶制剂,将TG酶用于肉糜类速冻调理肉制品中改善产品质构,研制出新型的方便快捷速冻调理禽肉制品,并且筛选出最佳的原料配比:去皮胸碎肉70%、鸡皮30%,水50%。最佳辅料配比:TG酶0.2%,香辛料0.25%,香精0.4%,三聚磷酸盐0.3%,焦磷酸盐0.15%,异抗坏血酸钠0.05%,红曲红0.008%,木薯变性淀粉12%,大豆分离蛋白3%,卡拉胶0.3%。     

Isolation of novel homopolysaccharide-producing lactic acid bacteria from Romanian raw milk and fermented dairy products

Traditionally fermented foods can be a rich source of diverse lactic acid bacteria (LAB) with interesting functional properties, such as exopolysaccharide (EPS) production. The objectives of this study were to map the mucoid and/or ropy LAB isolated from raw milk and traditionally fermented dairy products, collected in different regions of Romania, to study the species diversity within the samples and to further explore the EPS-producing capacity of the isolates. Seventy-three LAB strains were isolated and identified through (GTG)₅-PCR genomic fingerprinting and SDS-PAGE of whole-cell proteins. Lactococcus lactis was the most frequently encountered species, followed by Lactobacillus plantarum, Leuconostoc spp., and Enterococcus spp. Nine strains produced homopolysaccharides (HoPS, glucose monomers), namely L. lactis 1.8; Leuc. citreum 1.10, 1.11, 1.12, 2.8, and 4.11; Leuc. mesenteroides 21.2; Leuc. pseudomesenteroides 20.6; and Weisella confusa/cibaria 38.2, six of them in the concentrations above 10 g/L, both in milk and MRS medium supplemented with sucrose. In all EPS, the glucose constituents were connected by different α-linkages, among which α-1,6-linkages were the most prevalent.     

SaniTwice: a novel approach to hand hygiene for reducing bacterial contamination on hands when soap and water are unavailable

The risk of inadequate hand hygiene in food handling settings is exacerbated when water is limited or unavailable, thereby making washing with soap and water difficult. The SaniTwice method involves application of excess alcohol-based hand sanitizer (ABHS), hand "washing" for 15 s, and thorough cleaning with paper towels while hands are still wet, followed by a standard application of ABHS. This study investigated the effectiveness of the SaniTwice methodology as an alternative to hand washing for cleaning and removal of microorganisms. On hands moderately soiled with beef broth containing Escherichia coli (ATCC 11229), washing with a nonantimicrobial hand washing product achieved a 2.86 (±0.64)-log reduction in microbial contamination compared with the baseline, whereas the SaniTwice method with 62 % ethanol (EtOH) gel, 62 % EtOH foam, and 70 % EtOH advanced formula gel achieved reductions of 2.64 ± 0.89, 3.64 ± 0.57, and 4.61 ± 0.33 log units, respectively. When hands were heavily soiled from handling raw hamburger containing E. coli, washing with nonantimicrobial hand washing product and antimicrobial hand washing product achieved reductions of 2.65 ± 0.33 and 2.69 ± 0.32 log units, respectively, whereas SaniTwice with 62 % EtOH foam, 70 % EtOH gel, and 70 % EtOH advanced formula gel achieved reductions of 2.87 ± 0.42, 2.99 ± 0.51, and 3.92 ± 0.65 log units, respectively. These results clearly demonstrate that the in vivo antibacterial efficacy of the SaniTwice regimen with various ABHS is equivalent to or exceeds that of the standard hand washing approach as specified in the U.S. Food and Drug Administration Food Code. Implementation of the SaniTwice regimen in food handling settings with limited water availability should significantly reduce the risk of foodborne infections resulting from inadequate hand hygiene.