Campylobacter jejuni and its incidence in meat packaged under warm conditions

The problem of survival of Campylobacter jejuni was studied in artificially contaminated butchered meat packed in warm condition. Apart from the presence of Campylobacter jejuni, the total number of microorganisms and the shelf life of the meat were studied. With plain packing, Campylobacter jejuni survived six to seven days and the shelf life of the meat was about a week. In vacuum-packed meat Campylobacter jejuni was isolated for ten to eleven days and sensory changes occurred after ten to fourteen days. In meat packed in protective atmosphere Campylobacter jejuni was able to survive for ten to thirteen days and the meat kept its sensory properties for a fortnight or longer. There were no differences in the survival of Campylobacter jejuni in pork and beef, nor were there any substantial differences in the microorganism survival in PSE, DFD meat and in intact meat.     

Microbiological study of fresh and refrigerated meat products manufactured by REMA

Fresh meat semi-finished food REMA was demonstrated to be highly contaminated by bacteria. In more than 50% of the samples of most kinds of the examined fresh semi-finished food, the total counts of mesophile microorganisms (CPM) exceeded the internationally admissible limit for human consumption, i. e. 10(5) per g microorganisms. The greatest differences in the microorganism counts in fresh and stored samples were found in CPM and in the counts of psychrotolerant microorganisms. The counts of CPM and psychrotolerant microorganisms were differentiated and ranged from 10(5) per g to 10(13) per g when the first organoleptic symptoms of spoilage appeared. The organoleptic symptoms of spoilage of REMA semi-finished food are promoted by mesophile microorganisms which can grow also at the temperature of +4 degree C. No salmonellae with selective multiplication were observed in any sample.     

Clostridia in carcasses and fresh meat--a literature review]

Clostridia are of large clinical importance as well as in the field of food hygiene, where they are responsible for spoilage but they also have a certain significance as food poisoning organisms. Information on the ecology of Clostridia in samples of deep muscle tissue of slaughtered animals is insufficient. This article is intended to increase the knowledge on the occurrence of different Clostridia species in slaughtered animals. The main emphasis is put on the significance of clostridia in meat hygiene. The theoretical basis of the so called original content of microorganisms (intrinsic bacteria), the factors and pathways of Clostridia spreading in muscles and organs are demonstrated.     

Lung cancer risk in workers in the meat and poultry industries--a review

Laboratory and in vivo studies in primates, and serological evidence in humans, indicate that food animal oncogenic viruses show potential for causing cancer in humans. However, until fairly recently, supporting analytic epidemiologic studies have been lacking and have concentrated on lung cancer. We conducted an extensive Medline search and reviewed 60 studies investigating lung cancer risk in highly exposed workers in the meat and poultry industries. The overwhelming majority of studies of different designs (including all the cohort mortality and cancer incidence studies) indicate at least a 30% excess risk of lung cancer in meat and poultry plant workers, even after controlling for smoking. Evidence points to food animal oncogenic microorganisms as one of the main causes. This has important public health implications because the general population is also widely exposed. Studies carried out thus far have not had sufficient statistical power to investigate other potentially carcinogenic exposures within the industries. Thus, large studies that can adequately control for occupational and non-occupational confounding factors are needed, so that the possible role of food animal oncogenic viruses in the occurrence of human lung cancer can be clearly defined.     

肉鸡肌肉品质的研究现状与趋势

鸡肉是人们食物结构中的重要肉食来源之一。但目前鸡肉产量的增加与肉品品质的下降的矛盾正成为人们关注的热点。本文综述了肉鸡肌肉品质概念、评价系统与方法、影响肌肉品质的因素,并对鸡肉品质研究方向进行了预测。     

新疆肉羊产业发展制约因素及对策研究

肉羊产业在新疆畜牧业中占据重要地位,饲养肉羊收入是许多农牧民收入的重要来源。但诸如草原退化、发展资金缺乏、生产方式落后、产业化程度低等因素却严重制约着新疆肉羊产业的继续发展。从新疆肉羊产业发展现状出发,分析制约其发展的主要因素,并提出有针对性的政策建议,以期为新疆政府制订肉羊产业政策提供依据。     

Quantitative occurrence of lipolytic and proteolytic enzymes in food of animal origin

Proteolytic and lipolytic enzymatic activities of microorganisms are the most important cause for food spoilage and a limited shelf life. Until now the determination of the total aerobic count is the base of shelf life evaluations. Our investigations show the proportion of proteolytes and lipolytes to the total germ count in different kinds of food (milk and milk products, meat products and fish) which is in part surprisingly high. Results were observed on different media--proteolytic germs were counted on protein containing agar (casein, meat protein, fish protein) and lipolytic organisms on fat containing agar (tributyrin, olive oil, butterfat). Using the predictive microbiology and the knowledge about the activity of microbial enzymes under different milieu conditions in food the results give an important tool for a better shelf life evaluation.     

植物提取物的抗氧化作用及其在养禽生产中的应用研究进展

植物提取物添加剂被认定为是"安全、高效、稳定、可控"的饲料添加剂,经过20多年的研究,已经市场化并用于饲料和动物生产。关于植物提取物类添加剂在杀灭或抑制病源性微生物,如沙门氏菌、埃希氏菌、金黄色葡萄球菌的研究方面已经有广泛报道。本文综述了有关植物提取物的体内外抗氧化作用、对禽肉和禽蛋在储藏期间的抗氧化稳定性,及其对家禽生产和繁育性能的影响研究的最新进展。     

Prevalent organisms on ostrich carcasses found in a commercial abattoir

The prevalent microbial growth on carcasses before and after overnight cooling in an ostrich abattoir and de-boning plant was investigated. The effect of warm or cold trimming of the carcasses was examined together with possible causes of contamination along the processing line. An attempt was made to link the prevalent microorganisms that were identified from carcasses to those from specific external contamination sources. Samples of carcasses and possible contaminants were collected in the plant, plated out and selected organisms were typed using a commercial rapid identification system. It was indicated that the cold trim (mainly of bruises) of carcasses was advantageous in terms of microbiological meat quality. Results indicated pooled water in the abattoir as the most hazardous vector for carcass contamination and that contaminants from this source are mostly Gram-negative pathogens. Pseudomonas and Shigella were frequently isolated from surface and air samples and indicated that the control of total plant hygiene is a requirement for producing ostrich meat that is safe to consume and has an acceptable shelf-life.     

Food as a potential vector for antibiotic resistances. 2: Relevance of lactic acid bacteria

Transfer of antibiotic resistances via the food chain is possible through the ingestion of resistant parts of the original food microflora. Lactic acid bacteria (especially glycopeptide resistant enterococci) are considered as important vectors because of their ability to transfer resistances by genetic mechanisms. Therefore a literature review and own investigations concerning the incidence and the resistance profile of enterococci from fresh meat were performed. The isolates harboured in part resistances relevant for human medicine. However, they could be isolated only sporadically and could not be demonstrated quantitatively in most cases. The resistance profile differed from those of human clinical origin. These results were confirmed by other authors. Additionally other investigators could prove molecular differences compared to clinical strains. Therefore food can only be considered as a vector if resistance transfer from food isolates to pathogenic microorganisms is possible. Such a transfer could be shown only in very low frequencies. In conclusion so far lactic acid bacteria cannot be considered as the main source for the incidence of antibiotic resistances in man.     

青海东部地区海东鸡鸡肉肉质检测分析报告

本文对海东鸡和卡力岗鸡鸡肉肉质品质成份进行了检测,并对检测数据进行了单因素方差分析.结果表明：海东鸡鸡肉肉质主要营养成份,蛋白质、铁、棕榈酸、亚油酸和一些主要氨基酸如天冬氨酸、苏氨酸、丝氨酸、缬氨酸、异氨酸、异亮氨酸、酪氨酸和苯丙氨酸等均高于卡力岗鸡鸡肉主要营养成份的含量.     

Regulation of taste-active components of meat by dietary leucine

1. Regulation of meat taste is one effective method for improvement of meat quality. In this study, effects of dietary leucine (Leu) content on taste-active components, especially free glutamate (Glu), in meat were investigated. 2. Broiler chickens (28 d old) were fed on diets with graded dietary Leu content (100, 130 or 150% of Leu requirement in NRC, 1994) for 10 d before marketing. Taste-active components of meat (free amino acids and ATP metabolites) and sensory score of meat soup were estimated. 3. Free Glu content, the main taste-active component of meat, was significantly increased by dietary Leu. Compared with the Leu 130% group, free Glu was increased by 17% in the Leu 100% group. Free Glu of meat tended to decrease in the Leu 150% group. In contrast, inosine monophosphate content in meat did not change among all groups. 4. Sensory evaluation of meat soup from the Leu 100 and 150% groups showed that they had different meat tastes. Sensory scores of overall preference, umami taste and chicken-like taste were significantly higher in the Leu 100% group. 5. These results suggest that dietary Leu content is a regulating factor of free Glu in meat. Decreasing dietary Leu induces an increase in the free Glu content of meat and improves meat taste.     

肉制品中生物胺的控制技术及其检测方法的研究进展

生物胺是氨基酸在脱羧酶作用下脱羧后的产物,是植物和微生物体内具有生物活性的含氮化合物,参与机体正常的生理调节,少量的生物胺也有利于人体和动物生理活动。但是,当人体摄入量过多时会引起食物中毒。作者就肉制品中生物胺技术控制和干预及检测方法进行了综述。     

鲁西黄牛背截面指标为参数的胴体产肉率回归分析

７头商品鲁西牛胴体第１１肋后缘截面的客观测量值及相应的其它屠宰数据应用ＳＡＳ软件对胴体产肉率进行了回归分析,结果表明半胴体重、皮下脂肪厚、背眼肌面积、腔脂％组建的四元方程对后腿分割肉产率的预测力最大,其次是后躯分割肉产率、全部可食肉产率、主要分割肉产率对全部分割肉产率的预测力最小。眼肌面积是主要分割肉产率最重要的独立预测指标;腔脂％对全部分割肉产率、全部可食肉产率、后躯分割肉产率单独的预测作用最大     

试论破解中国“调猪”向“调肉”转变困境的方法

文章论述了"调猪"向"调肉"转变的历史背景,进行了冷却肉代替常温鲜肉的可行性论证,加强对冷却肉营养价值高,口味几乎与常温鲜肉媲美等关于冷却肉的知识宣传,让冷却肉成为肉类消费主流产品,是破解"调猪"向"调肉"困境的主要方法。尖锐指出目前排名前十的猪企纷纷布局的,大城市大型屠宰和肉联厂项目,是走"调猪"的老路和死胡同,会造成极大的资源浪费。提出在生猪主产区建立肉联厂,充分利用和整合现有肉联厂资源,配齐官方兽医,加强产地检疫和屠宰检疫,加快非洲猪瘟快速检测试纸的研发,加强冷却肉加工、质量控制技术研究和国家标准的制订,中国肉类加工企业协会,承接国家主管部门移交的肉类加工社会管理职能等建议,供同行参考。     

Reduction of dietary lysine increases free glutamate content in chicken meat and improves its taste

Taste is a crucial factor of meat quality, and amino acids are important taste‐active components in meat. Here, the effects of dietary lysine (Lys) content on taste‐active components in meat, especially free glutamate (Glu), were investigated. Twenty‐eight‐day‐old broilers (Gallus gallus) were fed diets with graded Lys content of 90% or 100% of the recommended Lys requirement, (according to the National Research Council, 1994 ) for 10 days. Free amino acid content in meat and sensory scores of meat soup were estimated. Free Glu content, the main taste‐active component of meat, was significantly increased by a reduction of dietary Lys. Compared with the Lys 100% group (control), free Glu concentrations of meat were increased by 35.7% in the Lys 90% group (P < 0.05). In addition, free glycine, valine, isoleucine, leucine, histidine and threonine concentrations of meat were significantly increased in the Lys 90% group (P < 0.05). Sensory evaluation of meat soup made from the Lys 100% and 90% groups indicated different meat tastes. Sensory scores of taste intensity, umami and kokumi tastes were significantly higher in the Lys 90% group. These results suggest that a reduction of dietary lysine increased free glutamate content in meat and improved its taste.     

Animal health and foodborne pathogens: enterohaemorrhagic O157:H7 strains and other pathogenic Escherichia coli virotypes (EPEC,ETEC, EIEC,EHEC)

The majority of interactions between microorganisms and animals are based on convenient relations for both of them. Symbiotic microorganisms, like intestinal microbiota, produce important vitamins for animals and protects them from putative pathogens. In general, for monogastric animals, the main contribution of intestinal microorganisms is to supply with growth factors the animal diet, and in some cases they are responsible for providing essential vitamins (e.g. vitamin K). Some particular and relatively few microbes like viruses, bacteria, fungi, protozoa and algae are responsible for animal illness. Because microorganisms are easily dispersed, display physiological diversity, and tolerate extreme conditions, they are ubiquitous and may contaminate and grow in many products, including food and raw materials. Foodborne diseases are caused by consumption of contaminated food or beverages. Many different disease-causing pathogens can contaminate food, so there are many different foodborne infections. In addition, poisonous chemicals and biological toxins can cause disease if they are present in food. To know how a particular disease is spreading is an important matter to take appropriate steps to stop it. For example Escherichia coli O157:H7 infections can spread through contaminated food (meat, vegetables, cheese, etc.), contaminated drinking water or juices, contaminated swimming water and from person to person. Among foodborne pathogens, the most frequently detected are bacteria, but also parasitic protozoa and worms, viruses, natural toxins and other pathogenic agents like prions are important agents for foodborne diseases. Particular pathogenic types of E. coli, classified by their specific pathogenic mechanisms (toxins, adhesins, invasiveness, etc.) are actually known as E. coli virotypes. Enterohaemorrhagic E. coli (EHEC), which constitute the main part of this review, were also named verotoxigenic E. coli (VTEC) or Shiga toxigenic E. coli (STEC). EHEC strains cause haemorrhagic colitis (HC), haemolytic uremic syndrome (HUS) and thrombotic thrombocytopaenic purpura (TP) in humans. They synthetize shigatoxins (verotoxins) which are potent cytotoxic substances, adherence factors and enterohaemolysin. EHEC are responsible for many outbreaks of bloody diarrhoea caused by contaminated foods: beef, milk, fruits, juice, water, etc. The most important serogroups among EHEC are O26, O111 and O157, being O157:H7 the most relevant serotype in foodborne outbreaks. The normal intestinal microflora of cattle was found to be the most relevant reservoir of EHEC strains.     

国外肉牛饲料添加剂的研究进展

为全面了解肉牛饲料添加剂的最新研究进展,作者总结了近期国外肉牛养殖中饲料添加剂使用的文献报道,主要对甘油、抗生素、矿物质、维生素、微生物及脂类6类饲料添加剂在肉牛养殖中的应用进行了综述,集中在不同饲料添加剂对肉牛瘤胃发酵、生产性能、消化性能和肉品质的影响。饲料添加剂对于肉牛生产十分重要,其使用方法、使用效果的发挥都很关键。日粮类型和精粗比会影响甘油的使用效果;抗生素混合使用效果优于单独使用;不同形态和不同添加量的微量元素和维生素对肉牛生长发育及机体免疫力具有促进和提高的作用。因此,在实际生产中,应综合考虑各种影响因素,根据肉牛的营养需要选择合适的饲料添加剂种类及适宜的比例,合理应用,最大程度地发挥其应用效果,进而获得更高的经济效益。作者总结和分析了肉牛饲料添加剂的国外研究成果,以期为中国肉牛产业的发展提供理论依据。     

花·马杂交F1公鹿与母本公鹿的屠宰试验

采用“屠宰性状测定方法”对应用人工授精技术手段所获得的西丰梅花鹿(♀)与天山马鹿(♂)杂交F1的头2、锯公鹿与母本西丰梅花鹿做了屠宰试验,结果表明,其主要肉用性状屠宰率、净肉重和净肉率分别为61.94%、59.05%、60.17%和62.34%;46.93 kg、48.16 kg、25.01 kg和35.45 kg;47.89%、45.86%、42.38%和46.04%。并确定此种杂交组合方式为适宜的肉用鹿杂交组合之一,为我国长白山鹿业的肉用鹿生产和市场开发提供了科学依据。     

不同属种肉类对大鼠血清生化指标与抗氧化能力的影响

探讨了不同属种肉类对大鼠血清生化指标和抗氧化机能的影响。试验选取体重约177 g的雄性SD大鼠90只,随机分为3组即狗肉组、羊肉组、鸭肉组,分别将日粮中的主要蛋白源替换为狗肉、羊肉、鸭肉(CP 31%)。试验期为4周。结果表明:饲喂狗肉和羊肉能显著提高大鼠生长性能,且前者使得大鼠血清碱性磷酸酶(ALP)活性极显著升高(P<0.01);而饲喂鸭肉使得大鼠血清丙氨酸转移酶(ALT)活性显著升高(P<0.05),天冬氨酸转移酶(AST)、血清尿素氮(BUN)活性极显著升高(P<0.01)。不同属种的肉之间,鸭肉组肝脏和肾脏中谷胱甘肽过氧化物酶(GSH-Px)活性均极显著升高(P<0.01)。结果提示:饲喂狗肉和羊肉能促进机体蛋白质合成,有利于蛋白质沉积;饲喂鸭肉则具有增强机体抗氧化的能力。