The nutritive values of feed proteins and feed protein residues resistant to degradation by rumen microorganisms

Fishmeal (FM), meat and bone meal (MBM) and rapeseed meal (RSM) were incubated for 8h (RSM) or 24 h (FM, MBM) in nylon bags in the rumens of cattle, in order to prepare from each meal sufficient residues resistant to rumen degradation for evaluation of their nutritive value. The nitrogen (N) and organic matter (OM) contents of FM and MBM were significantly (P<0.05) reduced by rumen incubation. The modified acid detergent fibre content of RSM was increased, and only traces of glucosinolates remained after rumen incubation. The amino acid profiles of FM and RSM were observed to change as a result of rumen incubation, whereas that of MBM was unchanged. The true N digestibilities of all three protein meals when fed to rats as the sole protein source were significantly (P<0.05) reduced by prior rumen incubation (FM, 0.90 to 0.86; MBM, 0.81 to 0.55 and RSM, 0.76 to 0.67). When measured using a rat bioassay, the biological values of FM (65.0 to 79.2) and RSM (53.3 to 83.1) protein were significantly (P<0.05) increased as a result of rumen incubation but that of MBM was unchanged (47.7 vs 41.1). The N digestibility of the protein meals and of their residues resistant to rumen degradation were also estimated in cattle. Samples of the feedstuffs were placed in small polyester bags, inserted into the proximal duodenum of cattle, recovered in faeces and N disappearance from the bags measured. This technique ranked the N digestibilities of the feedstuffs in the same order as in the rat.     

酶联免疫法测定食品和饲料中的黄曲霉毒素

本实验应用酶联免疫方法对食品和饲料中的黄曲霉毒素进行测定,奶粉中黄曲霉毒素M1的多次重复测定的结果的变异系数小于12%,回收率接近90%。说明本试剂盒测定结果比较精确,重现性较好。食品辅料及饲料中的黄曲霉毒素B1的测定结果的变异系数小于15%,说明实验结果的重现性较好。     

酶联免疫法测定食品和饲料中的黄曲霉毒素

本实验应用酶联免疫方法对食品和饲料中的黄曲霉毒素进行测定，奶粉中黄曲霉毒素M1的多次重复测定的结果的变异系数小于12％，回收率接近90％。说明本试剂盒测定结果比较精确，重现性较好。食品辅料及饲料中的黄曲霉毒素B1的测定结果的变异系数小于15％。说明实验结果的重现性较好。     

食品微生物质量控制技术

正近年来,由微生物引起的食品安全事件时有发生,食品中的微生物包括食源性致病菌(沙门氏菌、单核细胞增生李斯特菌、金黄色葡萄球菌、副溶血性弧菌、大肠杆菌等)和腐败菌(霉菌、酵母菌等)。这些微生物严重威胁人类的健康,所以对于食品中微生物的控制、灭活、风险评估及耐药性分析显得尤为重要。本文将重点从食品微生物质量控制的角度介绍本期的主要内容。     

利用选择性培养基快速初步鉴定食品中的致病微生物

目的 建立快速区分鉴别某种(类)微生物的方法。方法 选择几种常用的培养基, 将不同的菌株接种在培养基上, 通过培养基成分对不同微生物的选择性、显色反应及不同菌株在选择性培养基上具有的特征性菌落形态, 初步并快速判定微生物, 尤其是致病类微生物。结果 大肠埃希氏菌会与其他致病菌混淆, 可以通过结晶紫中性红胆盐(crystal violet neutral red bile salt, VRBA)琼脂将其区分; 志贺氏菌在培养基上菌落基本均为半透明, 体现的均为培养基本身的颜色; 亚硫酸铋(sulfurous acid bismuth, BS)琼脂的选择性较强, 但鼠伤寒沙门氏菌在该培养基上长势良好。结论 该方法可有效提高鉴别致病菌的效率。     

Fungal biotechnology in food and feed processing

Fungi are of excellent value nutritionally, and of great importance to vegetarians. Edible mushrooms are excellent sources of protein, have low-fat content and are free of cholesterol. They are easily cultivable and are consumed either in fresh or processed form. Yeasts and filamentous fungi secrete a plethora of important enzymes in the growth medium together with other secondary metabolites. Most of these are hydrolytic in nature being employed in different food processing industries as well as in refinement of fodder quality. Edible filamentous fungi producing these enzymes present an added advantage for their use in food and feed. In this article these aspects will be discussed along with the results from edible mushroom Termitomyces clypeatus, producing a wide variety of hydrolytic enzymes and products, from our laboratory. It is likely that the functional understanding of different enzyme classes will provide new applications within the food industry in the future.     

Single cell protein as food and feed

This review pertains the current knowledge concerned with the application of SCP in human and animal nutrition. General factors limiting the utilization of microbial proteins in human nutrition, such as toxicological barriers, nutritive value and functional properties, are discussed. Special attention is paid to several modern procedures of protein extraction from microbial cells, reduction of nucleic acids level as well as preparation of protein isolates. According to the data presented the latter can be considered as valuable protein substitutes. Significantly less nutritive problems are being concerned with the application of SCP in animal nutrition. Successful feeding experiments with chicken and pigs are discussed. Under these experimental conditions 10-20% of the protein in the feedstuff can be replaced by SCP. Moreover, several in Poland obtained protein-vitamin preparations are described. These originated from selected yeast and propionic acid bacteria grown in whey and its ultrafiltrates and can be considered as valuable food and feed supplements.     

Early detection of food pathogens and food spoilage microorganisms: Application of metabolomics

BackgroundFood safety is a major issue, with a large number of people around the world suffering from illness due to the consumption of contaminated and unsafe food products. An early detection of food pathogens and spoilage microorganisms is an important step that can help to control a foodborne outbreak, thus avoiding the loss of a massive amount of food products.Scope and approachMetabolomics is generally a hypothesis generating tool that makes use of different analytical instruments to analyse as many metabolites as possible in a given biological sample. Metabolomics has already been successfully applied to different areas of food science. Here, I present metabolomics as a valuable tool for studying the metabolism of food pathogens and spoilage microorganisms.Key findings and conclusionsThe scientific area of metabolomics has improved tremendously over last decade. Due to the rapid development of instrumental platforms, it is now possible to analyse a wide range of metabolites present in food and produced by microorganisms. This approach has a high potential to determine biomarkers which can later be used for the development of early detection tools for food pathogens and spoilage microorganisms, thus ensuring a better management of food safety.     

Questions safety and tendency of using genetically modified microorganisms in food, food additives and food derived

In this article analysis questions of using genetically modified microorganisms in manufacture food production, present new GMM used in manufacture -food ferments; results of medical biological appraisal/ microbiological and genetic expert examination/ of food, getting by use microorganisms or there producents with indication modern of control methods.     

Detection of Salmonella in food,feed and veterinary samples by EU laboratories

The European Union Reference Laboratory (EURL) for Salmonella organises interlaboratory comparison studies on bacteriological detection of Salmonella in different matrices (veterinary, food and animal feed) amongst National Reference Laboratories for Salmonella of the 27 European Member States (EU-MS). The EURL also gives non-EU Member States (EU candidate countries, member countries of the European Free Trade Association (EFTA) and third countries from outside Europe) the opportunity to participate in these studies. The objective of the studies is to test the ability of the participating laboratories to detect Salmonella at different contamination levels in the various matrices. In addition a comparison is made between the prescribed method of the food and animal feed studies (ISO 6579: RVS and MKTTn) and the prescribed method of the veterinary studies (annex D of ISO 6579: MSRV).This article describes the performance of the individual laboratories in the interlaboratory comparison studies as organised by the EURL for Salmonella in the period 2004-2010.The performance of the majority of the NRLs improved during the course of the studies. Overall the NRL laboratories performed well and were able to detect Salmonella in the different tested matrices. After improvement of the samples, it was possible to define criteria for good performance in the studies organised since 2006. In the eight interlaboratory comparison studies organised in the period 2006–2010, 15 laboratories found in total 19 deviations of which eight concerned a false positive blank result. The other deviations concerned sensitivity problems (false negative results). After checking and improving several technical aspects, the underperforming participating laboratories were able to improve their performance in a follow-up study.     

微生物与酶制剂在秸秆发酵饲料生产中的应用

利用微生物的自身代谢活动与酶制剂而生产的发酵饲料正逐渐成为解决饲料紧张和环境问题的重要手段。微生物与酶制剂将难以直接消化吸收的农作物秸秆等原料转化成易被牲畜采食消化吸收的、营养价值更高且无毒害的发酵饲料。该文对发酵饲料的定义、在发酵饲料中应用的微生物与酶制剂和生产中存在的问题进行了阐述,并对微生物与酶制剂发酵饲料的进一步发展做了展望。     

黄曲霉毒素的分析方法

为了解黄曲霉毒素的检测方法，从采样与样品准备、提取净化、测定方法等方面对黄曲霉毒素的分析方法进行了综述。     

Resistance responses of microorganisms in food environments.

Food borne microorganisms display a broad spectrum of resistance responses to naturally occurring and intentionally added antimicrobial agents. Resistance may be conferred by innate structural features of the bacterial strain such as an impermeable outer membrane or a mechanism for antibiotic-inactivation. Bacteria previously susceptible to an antimicrobial compound can acquire resistance through mutation or through genetic transfer processes such as transformation, transduction, and conjugation. Resistance can also be conferred by biofilm formation on food processing surfaces as an adaptive response to protect colonies from cleaning and sanitation. Resistant pathogens are a global problem, facilitated by international trade of raw and processed foods. Cross resistance between clinical and nonclinical antimicrobials can exist and is of concern. The development of resistant foodborne pathogens has been attributed to increased antibiotic use in hospitals, outpatient facilities, and veterinary applications. Resistant microorganisms can also develop as a result of physical processes used in food preservation, such as acid treatments and irradiation processes. Strategies to effectively counter resistance development include: changing current practices of antibiotic usage, developing new antibiotics, applying hurdle preservation approaches, preventing bacterial adhesion, and utilizing competitive exclusion. This paper presents an overview of problems arising from the development of microbial resistance, and explores possible solutions for detecting and defeating the adaptive changes of microorganisms.     

食品微生物快速检测技术研究进展

从食品安全的角度出发，介绍了几种快速检测方法，同时，较系统的介绍了利用生物化学、免疫学和分子生物学的技术手段快速检测病原菌的技术和方法。     

食品微生物快速检测技术研究进展

从食品安全的角度出发,介绍了几种快速检测方法,同时,较系统的介绍了利用生物化学、免疫学和分子生物学的技术手段快速检测病原菌的技术和方法。     

Control of a range of food related microorganisms by a multi-parameter preservation system

Seventy-two process variables, based on a matrix of a _w nature of controlling solute, pH, and the addition of sodium citrate and sodium benzoate were examined with a view t o devising a food preservation system for ambient temperatures. Growth of a challenge'cocktail' of Staphylococcus aureus, Bacillus subtilis, Pseudomonas aeruginosa, Streptococcus faecalis, Lactobacillus casei and Clostridiurn perfringens, was assessed in a Brain Heart Infusion broth based model system. Each of the controlling factors had an effect on growth. The addition of sodium citrate (2% w /v) and sodium benzoate (2000 mg/I) enhanced the inhibitory effect. Reduction in a _w (1.00–0.94) and pH (7.0–5.5) in combination or as separate controlling factors increased any inhibition. Combinations of sodium chloride and glycerol were used as the controlling solute, and increasing the proportion of sodium chloride resulted in suppressed growth, irrespective of any change in a _w or pH. Combinations of sodium citrate and sodium benzoate with a pH less than 6.0 and an a, less than 0.95 inhibited any growth during a 42 day incubation period at 37°C, irrespective of the controlling solutes studied.     

The immunological reactivity indices (the humoral component) in persons in contact with mycotoxin-contaminated food products

Blood serum levels of immunoglobulins (IgG, IgA, IgM, IgD, IgE), concentration of complement components (C1-inhibitor, C3, C4, C5, C9) as well as the content of some protein fractions (transferrin, ceruloplasmin, haptoglobin, orosomucoid, alpha 1-antitrypsin, alpha 2-macroglobulin, albumin and prealbumin) in the plasma were assayed in subjects exposed (due to their occupational necessity) to food raw materials (wheat, corn, barley, combined fodder) contaminated with mycotoxins. A total of 50 subjects, who have been working from 1 to 15 years at grain-treating factories, were investigated. It has been shown that a long-term exposure to food and fodder products containing mycotoxins induces a growth of IgE level attended by a drop in IgG content, and a decrease in the concentration of the complement components C3 and C9, transferrin and orosomucoid.