泡椒凤爪微生物污染来源及辐照杀菌效果的研究

研究了泡椒凤爪生产流程中微生物污染来源、60Co-γ射线辐照杀菌效果、及不同剂量处理的产品在不同温度下微生物繁殖情况。结果表明:泡椒凤爪微生物污染主要途径是泡制和包装环节,这是产品卫生质量控制的关键控制点;60Co-γ射线对产品中微生物有很好的杀灭作用,能显著延长产品的保质期,辐照剂量为6 kGy时,产品在30℃、20℃、10℃温度条件下保藏,保质期比对照分别延长了53 d、120 d和180 d。     

Microbial Content of Nonsterile Therapeutic Agents Containing Natural or Seminatural Active Ingredients

The relationship was investigated between various chemical or pharmaceutical production processes and the extent of microbial contamination, of natural origin, of the resulting products. The products contained active ingredients of vegetable, enzymatic, or animal origin. It was concluded that (i) vegetable products practically free from microbes can be produced if the proper manufacturing steps are taken; (ii) sterilization of the media used to manufacture antibiotics, etc., produces products with little contamination; and (iii) products containing extracts of animal organs require careful refrigeration and addition of preservatives to produce acceptable levels of microbial contamination.     

Importance of good manufacturing practices in microbiological monitoring in processing human tissues for transplant

Skin allografts represent an important therapeutic resource in the treatment of severe skin loss. The risk associated with application of processed tissues in humans is very low, however, human material always carries the risk of disease transmission. To minimise the risk of contamination of grafts, processing is carried out in clean rooms where air quality is monitored. Procedures and quality control tests are performed to standardise the production process and to guarantee the final product for human use. Since we only validate and distribute aseptic tissues, we conducted a study to determine what type of quality controls for skin processing are the most suitable for detecting processing errors and intercurrent contamination, and for faithfully mapping the process without unduly increasing production costs. Two different methods for quality control were statistically compared using the Fisher exact test. On the basis of the current study we selected our quality control procedure based on pre- and post-processing tissue controls, operator and environmental controls. Evaluation of the predictability of our control methods showed that tissue control was the most reliable method of revealing microbial contamination of grafts. We obtained 100 % sensitivity by doubling tissue controls, while maintaining high specificity (77 %).     

Use of PCR analysis for detecting low levels of bacteria and mold contamination in pharmaceutical samples

PCR assays were developed and compared to standard methods for quality evaluation of pharmaceutical raw materials and finished products with low levels of microbial contamination. Samples were artificially contaminated with less than 10 CFU of Escherichia coli, Staphylococcus aureus, Pseudomonas aeruginosa, and Aspergillus niger. Bacterial DNA was extracted from each enrichment broth by mild lysis in Tris-EDTA-Tween 20 buffer containing proteinase K while mold DNA was extracted by boiling samples in Tris-EDTA-SDS buffer for 1 h. A 10-microl aliquot of extracted DNA was added to Ready-To-Go PCR beads and specific primers for E. coli, S. aureus, and P. aeruginosa. However, 50-microl aliquots of extracted mold DNA were used for amplification of specific A. niger DNA sequences. Standard methods required 6-8 days while PCR detection of all microorganisms was completed within 27 h. Low levels of microbial contamination were detected in all raw materials and products using PCR assays. Rapid quality evaluation of pharmaceutical samples resulted in optimization of product manufacturing, quality control, and release of finished products.     

Microbial ecology and quality assurance in food fermentation systems. The case of kefir grains application

Fermentation technology has become a modern method for food production the last decades as a process for enhancing product stability, safety and sensory standards. The main reason for this development is the increasing consumers’ demand for safe and high quality food products. The above has led the scientific community to the thorough study for the appropriate selection of specific microorganisms with desirable properties such as bacteriocin production, and probiotic properties. The main food products produced through fermentation activity are bread, wine, beer cheese and other dairy products. The microorganisms conducting the above processes are mainly yeasts and lactic acid bacteria. The end products of carbohydrate catabolism by these microorganisms contribute not only to preservation as it was believed years ago, but also to the flavour, aroma and texture and to the increase of the nutritional quality by thereby helping determine unique product characteristics. Thus, controlling the function of specific microorganisms or the succession of microorganisms that dominate the microflora is therefore advantageous, because it can increase product quality, functionality and value. Throughout the process of the discovery of microbiological diversity in various fermented food systems, the development of starter culture technology has gained more scientific attention, and it could be used for the control of the manufacturing operation, and management of product quality. In the frame of this review the presentation of the quality enhancement of most consumed fermented food products around the world is attempted and the new trends in production of fermented food products, such as bread is discussed. The review is focused in kefir grains application in bread production.     

啤酒腐败微生物与啤酒微生物稳定性研究进展

尽管生产环境和卫生条件已经得到大幅改善,但啤酒生产过程中仍然会发生微生物污染,因此,真正意义上的啤酒纯种酿制是很难实现的。为了有效控制生产过程中的微生物污染,本文系统介绍了啤酒微生物的多样性及其在生产工序中的分布,探讨了啤酒环境对抑制啤酒微生物污染的影响,讨论了啤酒微生物对啤酒质量与风味的积极贡献,提出合理控制外源微生物侵染是形成不同啤酒典型特征的关键。     

Quality analysis of commercial <Emphasis Type="Italic">Chlorella</Emphasis> products used as dietary supplement in human nutrition

Chlorella vulgaris is one of the best-studied phototrophic eukaryotes. From the 1950s on, C. vulgaris and some other algal species were cultivated in huge quantities to meet the growing demand for alternative protein sources. After drying, algal biomass can be merchandised as tablets, capsules, extract or powder with specific biochemical qualities. However, the products quality, e.g. the containing species, microbial contamination or content and quality of pigments varies enormously. In this study, commercial Chlorella products, unprocessed Chlorella powders and several production strains were investigated. Molecular analysis of the 18S rDNA confirmed either the existence of more than one species per product or only other green algae species in about half of the samples tested. Many of the examined samples contained critical amounts of bacterial contaminations. Furthermore, cyanobacteria were detected in some of the samples. The content of chlorophyll a varied greatly between the samples and pheophytin, a degradation product of chlorophyll, was detected in some samples in large concentrations. These data indicate that quality control of microalgal products is an important issue that should be addressed by the manufactures.     

Application of pulsed light technology for fruits and vegetables disinfection: A review

Non-thermal technologies can maintain fruit and vegetable products quality better than traditional thermal processing. Pulsed light (PL) is a non-thermal method for microbial inactivation (vegetative cells and spores) in fruits and vegetables. The PL treatment involves the application of intense and short-duration pulses of broad spectrum wavelengths ranging from UV to near-infrared (100–1100 nm). This review summarized application of PL technology to control microbial contamination and increasing shelf-life of some fruits and vegetables including apple, blueberries, grape, orange, strawberries, carrot, lettuce, spinach, and tomato. The microbial inactivation in very short treatment times, low energy used by this system, flexibility for solid or liquid samples, few residual compounds and no synthetic chemicals that cause environmental pollution or harm humans, is benefits of PL technique. The efficiency of PL disinfection is closely associated with the input voltage, fluence (energy dose), composition of the emitted light spectrum, number of lamps, the distance between samples and light source, and frequency and number of applied pulses. The PL treatments control pathogenic and spoilage microorganisms, so it facilitates the growth and development of the starter microorganisms affecting product quality.     

Industrial production of heterologous proteins by fed-batch cultures of the yeast Saccharomyces cereuisiae

Abstract: This review concerns the issues involved in the industrial development of fed-batch culture processes with Saccharomyces cereriviae strains producing heterologous proteins. Most of process development considerations with fed-batch recombinant cultures are linked to the reliability and reproducibility of the process for manufacturing environments where quality assurance and quality control aspects are paramount. In this respect, the quality, safety and efficacy of complex biologically active molecules produced by recombinant techniques are strongly influenced by the genetic background of the host strain, genetic stability of the transformed strain and production process factors. An overview of the recent literature of these culture-related factors is coupled with our experience in yeast fed-batch process development for producing various therapeutic grade proteins. The discussion is based around three principal topics: genetics, microbial physiology and fed-batch process design. It includes the fundamental aspects of yeast strain physiology, the nature of the recombinant product, quality control aspects of the biological product, features of yeast expression vectors, expression and localization of recombinant products in transformed cells and fed-batch process considerations for the industrial production of Saccharomyces cerevisiae recombinant proteins. It is our purpose that this review will provide a comprehensive understanding of the fed-batch recombinant production processes and challenges commonly encountered during process development.     

Heterologous production of resveratrol in bacterial hosts: current status and perspectives

The polyphenol resveratrol (3,5,4′-trihydroxystilbene) is a well-known plant secondary metabolite, commonly used as a medical ingredient and a nutritional supplement. Due to its health-promoting properties, the demand for resveratrol is expected to continue growing. This stilbene can be found in different plants, including grapes, berries (blackberries, blueberries and raspberries), peanuts and their derived food products, such as wine and juice. The commercially available resveratrol is usually extracted from plants, however this procedure has several drawbacks such as low concentration of the product of interest, seasonal variation, risk of plant diseases and product stability. Alternative production processes are being developed to enable the biotechnological production of resveratrol by genetically engineering several microbial hosts, such as Escherichia coli, Corynebacterium glutamicum, Lactococcus lactis, among others. However, these bacterial species are not able to naturally synthetize resveratrol and therefore genetic modifications have been performed. The application of emerging metabolic engineering offers new possibilities for strain and process optimization. This mini-review will discuss the recent progress on resveratrol biosynthesis in engineered bacteria, with a special focus on the metabolic engineering modifications, as well as the optimization of the production process. These strategies offer new tools to overcome the limitations and challenges for microbial production of resveratrol in industry.     

Microbial export of lactic and 3-hydroxypropanoic acid: implications for industrial fermentation processes

Lactic acid and 3-hydroxypropanoic acid are industrially relevant microbial products. This paper reviews the current knowledge on export of these compounds from microbial cells and presents a theoretical analysis of the bioenergetics of different export mechanisms. It is concluded that export can be a key constraint in industrial production, especially under the conditions of high product concentration and low extracellular pH that are optimal for recovery of the undissociated acids. Under these conditions, the metabolic energy requirement for product export may equal or exceed the metabolic energy yield from product formation. Consequently, prolonged product formation at low pH and at high product concentrations requires the involvement of alternative, ATP-yielding pathways to sustain growth and maintenance processes, thereby reducing the product yield on substrate. Research on export mechanisms and energetics should therefore be an integral part of the development of microbial production processes for these and other weak acids.     

Metabolic Energy-Based Modelling Explains Product Yielding in Anaerobic Mixed Culture Fermentations

The fermentation of glucose using microbial mixed cultures is of great interest given its potential to convert wastes into valuable products at low cost, however, the difficulties associated with the control of the process still pose important challenges for its industrial implementation. A deeper understanding of the fermentation process involving metabolic and biochemical principles is very necessary to overcome these difficulties. In this work a novel metabolic energy based model is presented that accurately predicts for the first time the experimentally observed changes in product spectrum with pH. The model predicts the observed shift towards formate production at high pH, accompanied with ethanol and acetate production. Acetate (accompanied with a more reduced product) and butyrate are predicted main products at low pH. The production of propionate between pH 6 and 8 is also predicted. These results are mechanistically explained for the first time considering the impact that variable proton motive potential and active transport energy costs have in terms of energy harvest over different products yielding. The model results, in line with numerous reported experiments, validate the mechanistic and bioenergetics hypotheses that fermentative mixed cultures products yielding appears to be controlled by the principle of maximum energy harvest and the necessity of balancing the redox equivalents in absence of external electron acceptors.     

Drop-on-Demand System for Manufacturing of Melt-based Solid Oral Dosage: Effect of Critical Process Parameters on Product Quality

The features of a drop-on-demand-based system developed for the manufacture of melt-based pharmaceuticals have been previously reported. In this paper, a supervisory control system, which is designed to ensure reproducible production of high quality of melt-based solid oral dosages, is presented. This control system enables the production of individual dosage forms with the desired critical quality attributes: amount of active ingredient and drug morphology by monitoring and controlling critical process parameters, such as drop size and product and process temperatures. The effects of these process parameters on the final product quality are investigated, and the properties of the produced dosage forms characterized using various techniques, such as Raman spectroscopy, optical microscopy, and dissolution testing. A crystallization temperature control strategy, including controlled temperature cycles, is presented to tailor the crystallization behavior of drug deposits and to achieve consistent drug morphology. This control strategy can be used to achieve the desired bioavailability of the drug by mitigating variations in the dissolution profiles. The supervisor control strategy enables the application of the drop-on-demand system to the production of individualized dosage required for personalized drug regimens.     

VivaGel (SPL7013 Gel): a candidate dendrimer--microbicide for the prevention of HIV and HSV infection

Microbicides are compounds that applied vaginally or rectally, protect the user from sexually transmitted infections. Although no commercial product is yet available, many candidates are under development. A leading candidate, VivaGel (SPL7013 Gel) is the product of nanotechnology. The active ingredient is SPL7013, a dendrimer that was designed specifically with HIV and HSV antiviral activity and human safety in mind. SPL7013 has demonstrated efficacy against human immunodeficiency virus and herpes simplex virus in in vitro and animal models. VivaGel appears to be well tolerated in both animals and humans. This review summarizes the studies of VivaGel and its active ingredient, SPL7013.     

Tracing and control of raw materials sourcing for vaccine manufacturers

The control of the raw materials used to manufacture vaccines is mandatory; therefore, a very clear process must be in place to guarantee that raw materials are traced. Those who make products or supplies used in vaccine manufacture (suppliers of culture media, diagnostic tests, etc.) must apply quality systems proving that they adhere to certain standards. ISO certification, Good Manufacturing Practices for production sites and the registration of culture media with a ‘Certificate of Suitability’ from the European Directorate for the Quality of Medicines and Healthcare are reliable quality systems pertaining to vaccine production. Suppliers must assure that each lot of raw materials used in a product that will be used in vaccine manufacture adheres to the level of safety and traceability required. Incoming materials must be controlled in a single ‘Enterprise Resource Planning’ system which is used to document important information, such as the assignment of lot number, expiration date, etc. Ingredients for culture media in particular must conform to certain specifications. The specifications that need to be checked vary according to the ingredient, based on the level of risk.The way a raw material is produced is also important, and any aspect relative to cross-contamination, such as the sanitary measures used in producing and storing the raw material must be checked as well. In addition, suppliers can reduce the risk of viral contamination of raw materials by avoiding purchases in countries where a relevant outbreak is currently declared.     

Lactic-acid fermentation as a low-cost means of food preservation in tropical countries

Abstract The range of traditional lactic-acid-fermented foods in tropical countries is briefly reviewed. Recent studies on the lactic acid fermentation of fish and cassava products are described. Lactic-acid-fermented fish products may offer considerable scope for the development of new food products and for the use of under-utilised fish species. Lactic-acid-fermented fish products are common in parts of Asia; methods to improve the product and shelf-life quality, to reduce microbial risks and to accelerate the process are described. This work is based on fish/salt/carbohydrate model systems. The nutritional aspects of cassava fermentation are discussed with respect to factors involved in determining residual cyanide levels; the possible anti-nutritional rôle of condensed tannins is mentioned. The increasing consumption of meat products in tropical countries emphasises the need for a preservation method that does not depend on refrigeration. The possible production of sausage ingredients preserved by lactic acid fermentation, and the associated research needs are described.     

Regulatory affairs and biotechnology in Europe: III. Introduction into good regulatory practice — Validation of virus removal and inactivation

This paper provides for an overview on the practical consequences of the EC guideline (III/8115/89): Validation of Virus Removal and Inactivation. This guideline can only be used as a blueprint in combination with other specific guidelines, especially those concerned with EC recommendations during production and quality control for various biotech products.A potential risk associated with the production and use of biological products is viral contamination. This contamination may be present in the source material, eg. human blood, human or animal tissues, cell banks, or introduced in the manufacturing process through the use of animal sera (eg. foetal calf serum or trypsin) in cell culture supernatant.The objectives of validation are to establish — ideally both qualitatively as well as quantitatively — the overall level of virus clearance. Evidence of viral clearance must be obtained in all stages of purification and adequate viral removal and/or inactivation must be proven. The method used when validating viral removal and /or inactivation is by challenging the system through the deliberate addition (spiking) of significant amounts of virus into the crude material to be purified and to different fractions obtained during the various purification stages. Removal or inactivation of the virus during the subsequent stages of purification and /or inactivation is thereafter determined.Such a quality system is by no means a simple one: it is estimated that in some production lines around 600 Standard Operating Procedures are necessary to guarantee the quality and the safety of the desired biotechnological product. Small companies will probably not be able to perform all procedures needed for obtaining the desired quality of the product. Then, external laboratories may take over a part of the Part II development requirements, which may not be representative for the total of internal Quality Assurance. New developments in the production and quality control of biotechnological products may require that companies should introduce novel, sophisticated methods such as: polymerase chain reaction (PCR), as yet not recommended by the CPMP in detail.Abbreviations III/8115/89 EC     

Environmental monitoring in stem cell banks

The processing of stem cell lines for application in human therapy requires a physical environment in which air quality (i.e., the number of airborne particles) is controlled to minimize risk of contamination. The processing facility should be constructed and operated to minimise the introduction, generation and retention of particles and microorganisms. A formal program of environmental monitoring should be maintained in each stem cell bank to specify and assess key factors and their influence on the microbiological quality of the process and product. This program should assure the manipulation of cells involved in the derivation of stem cell lines and their culture under established limits for airborne particles and for microbial contamination of the air and surfaces. Environmental monitoring should also address the regulatory requirements in the countries in which the cells will be used. The monitoring programme will depend on local conditions in each processing centre or cell bank. Each centre will need to evaluate its specific needs and establish appropriate monitoring procedures which should not become intrusive to the extent that they might compromise the quality of the cell banks or products.     

Mini-review: microbial problems in paper production

Paper mills are open systems, which provide favorable conditions for microbial growth. Microbial contamination can cause substantial economic losses, including the deterioration of raw materials, interference with production processes by breakdowns and lowering product quality, and eventually, problems in wastewater treatment. Damage is caused by acidification, attack on raw materials, the formation of odorous products, discoloration of pigments, and the formation of methane and hydrogen, thereby producing potentially explosive conditions. Population analyses have revealed that a wide variety of microorganisms are involved, but there appear to be no typical strains associated with paper mills. Current trends in process engineering, such as chlorine-free bleaching, processing at neutral pH, closed cycles, and the use of recycled paper also favor microbial growth and biofilm (slime) formation. A fundamental problem associated with slimes is the extensive matrix of extracellular polymeric substances, which is composed of a large variety of highly hydrated polysaccharides, proteins, nucleic acids, and lipids. No ‘silver bullet’ against biofouling can be expected, and effective countermeasures have to be based on holistic approaches.     

涂料微生物污染与防腐剂使用情况关系的探讨

为了解涂料的微生物污染与防腐剂使用情况之间的关系,按照ISO 9252-1989(E)检测207件市售涂料微生物指标,利用高效液相色谱检测有微生物检出涂料和40件无微生物检出涂料的防腐剂使用情况。结果发现有12件涂料微生物超标;异噻唑啉酮类防腐剂是本实验检出使用最多的防腐剂;微生物超标涂料防腐剂含量比正常低或者未检测到,种类单一。涂料的防腐剂使用情况与微生物污染程度有着密切的联系,建议建立和完善涂料限用防腐剂标准,指导涂料企业安全生产和质量监督。