Antimicrobial properties of natural substances in irradiated fresh poultry

This study was undertaken to determine if a combined treatment (marinating in natural plant extracts or vacuum) with irradiation could have a synergetic effect, in order to reduce the dose required for complete elimination of Salmonella on fresh poultry. The effect of these combined treatments on the shelf-life extension was also evaluated. The fresh chicken legs were irradiated at 0, 3 and 5 kGy. The poultry underwent microbial analysis(mesophilic and Salmonella detection). For each treatment, the total microbial count decreased with increase of irradiation dose. The marinating treatment have a synergistic effect with irradiation treatment to reduce the total microbial count and controlling the proliferation during storage at 4°C. Irradiation of fresh chicken pieces with a dose of 3 kGy appears to be able to extend the microbial shelf-life by a factor of 2. When the chicken is marinating and irradiated at 3 kGy or when irradiated at 5 kGy without marinating, the microbial shelf-life is extended by a factor of 7 to 8. No Salmonella was found during all the experiment in the chicken in air and marinated. However, a presence of Salmonella was found in samples irradiated at 5 kGy under vacuum, in unirradiated samples and samples irradiated at 3kGy in air and under vacuum.     

Tegoprens in anaerobic digestion of a mixture of cheese whey,poultry waste,and cattle dung for improved biomethanation

To obtain enriched methane content and improve the anaerobic digestion of a mixture of cattle dung, poultry waste, and cheese whey, the effect of various doses of Tegoprens: T-3012, T-3022, T-5842, T-5843, T-5851, T-5852 has been studied, in bench-scale digesters. Among them, Tegoprens 3022 showed more than a 45% increase in gas production with higher methane content.     

Effectiveness of radiation processing in elimination of Campylobacter from poultry meat

Campylobacter, a common poultry intestine commensal, is a well known cause of human gastric illnesses across the globe. Consumption of contaminated poultry meat is a major cause of Campylobacter related infections. In the present study, radiation sensitivity of indigenous strains of C. jejuni and C. coli isolated from poultry was evaluated. The decimal reduction dose (D₁₀) values of different Campylobacter isolates at 0-4 °C in saline and blood broth were in the range of 0.120-0.210 kGy and 0.170-0.234 kGy, respectively. D₁₀ values in chicken meat homogenate for Campylobacter were in the range of 0.110-0.190 kGy. Chicken meat samples were inoculated with C. jejuni and exposed to gamma radiation to study the effectiveness of radiation treatment in elimination of Campylobacter. Radiation treatment with a dose of 1 kGy could achieve complete elimination of 10⁵ CFU of Campylobacter/g in poultry meat samples. No recovery of Campylobacter was observed, even after enrichment and selective plating in 1 kGy treated chicken meat samples stored at 4 °C up to 7 days. Present study shows that irradiation of poultry meat with 1 kGy can ensure safety of poultry meat.     

禽蛋中头孢噻肟残留的高效液相色谱-串联质谱法测定

建立了高效液相色谱-串联质谱(LC-MS/MS)测定禽蛋中头孢噻肟药物残留的方法。禽蛋样品中的头孢噻肟用纯水提取,乙腈沉淀蛋白,Oasis HLB(500 mg,6 mL)固相萃取柱净化,8 mL甲醇洗脱。采用Zorbax XDB-C18(2.1 mm×50 mm,3.5μm)色谱柱,以0.2%甲酸水-乙腈为流动相,0.3 mL/min梯度洗脱,经高效液相色谱分离后,采用电喷雾质谱正离子模式电离,多反应选择离子检测(MRM)模式测定。检测离子对为m/z456.1/396.1、m/z456.1/324.1,其中m/z456.1/396.1为定量离子对。在1.35~135μg/L范围内标准曲线的线性关系良好,相关系数为0.999 3;在1.0、50.0、100μg/kg3个添加水平的平均加标回收率为87%~99%,相对标准偏差为1.9%~3.9%;方法检出限为0.3μg/kg,定量下限为1.0μg/kg。该方法简便、灵敏、准确、可靠,适用于禽蛋中头孢噻肟药物残留的分析。     

禽肉中克球酚气相色谱微量快速测定法

对禽肉样品中克球酚药物残留采用微量化学法技术，以甲醇提取，氧化铝、阴离子树脂交换柱净化，乙酰化后，进行ＧＣ－ＥＣＤ毛细管色谱测定。经对肉鸡、填鸭、饲养山鸡进行添加回收率试验，方法回收率为８５．７％～９４．４％，变异系数为３．８％～７．７％，最低检出限为２．０ｎｇ／ｇ。     

Exploring Effects of Protease Choice and Protease Combinations in Enzymatic Protein Hydrolysis of Poultry By-Products

A study of the effects of single and combined protease hydrolysis on myofibrillar versus collagenous proteins of poultry by-products has been conducted. The aim was to contribute with knowledge for increased value creation of all constituents of these complex by-products. A rational approach was implemented for selecting proteases exhibiting the most different activity towards the major protein-rich constituents of mechanically deboned chicken residue (MDCR). An initial activity screening of 18 proteases on chicken meat, turkey tendons and MDCR was conducted. Based on weight yield, size exclusion chromatography (SEC) and SDS-PAGE, stem Bromelain and Endocut-02 were selected. Studies on hydrolysis of four different poultry by-products at 40 °C, evaluated by protein yield, SEC, and SDS-PAGE, indicate that the proteases’ selectivity difference can be utilized in tailor-making hydrolysates, enriched in either meat- and collagen-derived peptides or gelatin. Three modes of stem Bromelain and Endocut-02 combinations during hydrolysis of MDCR were performed and compared with single protease hydrolysis. All modes of the protease combinations resulted in a similar approximately 15% increase in product yield, with products exhibiting similar SEC and SDS-PAGE profiles. This shows that irrespective of the modes of combination, the use of more than one enzyme in hydrolysis of collagen-rich material can provide means to increase the total protein yield and ultimately contribute to increased value creation of poultry by-products.     

Detection of low amount of irradiated ingredients in non-irradiated precooked meals

The application of the European Standards for the detection of irradiated food by thermoluminescence of silicates, electron–spin resonance spectroscopy of bones or gas chromatography–mass spectrometry of 2-alkylcyclobutanones does not allow the detection of irradiated ingredients included in small quantity in the matrix of a food which has not been irradiated, but which could be subjected to various processing technologies such as cooking, freezing or storage. The use of an enzymatic food hydrolysis carried out at moderated temperature, for the extraction of the food-contaminating silicate minerals and bone fragments, followed by a purification of the extracts by a high-density aqueous solution of sodium polytungstate, allows a simultaneous detection of weak inclusions (0.1% m:m) of irradiated spices and mechanically deboned turkey meat (MRM) included in various precooked foods. Moreover, the use of a supercritical fluid extraction procedure for the 2-alkylcyclobutanones or an additional purification step of the lipid extracts made it possible to lower the detection limit of the 2-alkylcyclobutanones radiation-induced from triglycerides. Using gas chromatography–mass spectrometry, down to 0.5% (m:m) of irradiated MRM included in non-irradiated chicken quenelles could be detected.     

Analysis of emerging organic contaminants in poultry manure by gas chromatography–tandem mass spectrometry

A multiresidue method was developed for the determination of 19 emerging organic contaminants (pharmaceutical drugs, personal care products, and bisphenol A) in poultry manure. Lyophilized samples of manure were extracted by ultrasound‐assisted matrix solid‐phase dispersion and the extracts were analyzed by gas chromatography with tandem mass spectrometry after derivatization. Analysis of spiked poultry manure samples, at levels ranging from 25 to 150 ng/g, gave satisfactory recovery results for all the compounds, with values from 67 to 106%. The developed procedure provided detection limits that ranged from 0.9 to 2.2 ng/g. Finally, the validated method was applied to poultry manure samples collected from 23 poultry farms in Spain. Salicylic acid was found in most of the samples analyzed at levels up to 2501 ng/g, whereas, methyl paraben, orthophenylphenol, ibuprofen, paracetamol, and carbamazepine were detected at levels up to 250 ng/g. Composting of manure showed an important decrease in the levels of the detected contaminants.     

Antioxidant properties of natural substances in irradiated fresh poultry

This study was undertaken to determine if a combined treatment (marinating in natural plant extracts or vacuum) with irradiation could have a synergistic effect, in order to prevent the lipid oxidation resulting in the development of undesirable flavours. The fresh chicken legs were irradiated at 0,3 and 5 kGy. The fatty acids composition of lipids was identified using gas liquid chromatography. The effect of irradiation treatment combined with a pre-treatment on the fatty acids composition was followed. The day after irradiation, ten panallists were asked to evaluate, using the instruction scaling, the overall appearance, the odor, the flavor and the overall acceptability of the samples. The major fatty acids identified in lipids were oleic acid, palmitic acid, palmitoleic acid and stearic acid. Pre-treatments have a significant effect on linoleic acid (C18:2) and higher fatty acids. The unsaturated fatty acids derived from phospholipids appeared to be more affected by the irradiation dose: however, marinating have better protection on C18:2 derived from phospholipids. The results of sensory evaluation have shown a significant better odor and flavor for the irradiated chicken at 5 kGy than the control. No significant difference have been found between the marinated chicken, the chicken irradiated under vacuum and the control.     

热解温度对畜禽粪便制备的生物质炭性质的影响

以猪粪和鸡粪为原料,研究了热解温度(200~700 ℃)对生物质炭物理和化学性质的影响.结果表明,生物质炭的得率随着热解温度的升高逐渐降低,猪粪生物质炭的得率较鸡粪高;猪粪和鸡粪生物质炭的灰分含量分别为41.2%~70.6%和20.3%~48.1%.生物质炭均为中性或碱性,300~700 ℃热解所制备的生物质炭的pH值不仅与灰分含量有关,还可能与Ca含量密切相关.红外光谱表明,低温热解条件下（≤300 ℃）生物质炭中的含氧官能团与原材料相比无明显变化;但是当热解温度高于400 ℃时,生物质炭中的含氧官能团明显减少.生物质炭中的矿质元素含量均随着热解温度的升高而增大,猪粪生物质炭的富集倍数平均为1.04~1.65,鸡粪生物质炭为1.08~2.26.此外,猪粪K、Cu、Zn的挥发损失较鸡粪少,300~700 ℃热解鸡粪中K的挥发损失达30%;700 ℃热解,鸡粪Cu、Zn挥发损失达14.02%和21.70%.这些结果为畜禽固废制备生物质炭提供了重要的参考依据,为畜禽固废的资源化利用提供了新的思路.