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Is confidence in the monitoring of GE foods justified?

Often the limits of detection of genetically engineered organisms (GEOs, LMOs, GMOs) determine what legislation sets as thresholds of allowable contamination of the human food chain with GEOs. Many countries have legislation that is triggered by certain thresholds of contamination. Importantly, international trade in food and animal feed is becoming increasingly vulnerable to interruptions caused by the ambiguity GEOs can create when shipments are monitored at the border. We examine the tools available for detection. Four key error-generating stages are identified with the aim of prompting a higher uniform standard of routine analysis at export and import points. Contamination of the New Zealand corn crop with GEOs is used as a case study for the application of monitoring tools and vulnerability to errors. These tools fail to meet emerging food safety requirements, but some improvements are in development.

Consumer Product Safety↗

A probabilistic analysis of Clostridium perfringens growth during food service operations.

The purpose of this study was threefold: first, the study was designed to illustrate the use of data and information collected in food safety surveys in a quantitative risk assessment. In this case, the focus was on the food service industry; however, similar data from other parts of the food chain could be similarly incorporated. The second objective was to quantitatively describe and better understand the role that the food service industry plays in the safety of food. The third objective was to illustrate the additional decision-making information that is available when uncertainty and variability are incorporated into the modelling of systems.

Clostridium perfringens↗

People's concerns about biotechnology: some problems and some solutions.

Pharmaceuticals and vaccines made by genetic engineering are well accepted all over the world. In contrast, there are many people, particularly in Europe, who are worried that food, made by the same new technology, may harm their health or cause damage to the environment. This is despite the growing evidence that genetically modified crops have the potential to improve world food security and the fact that there have, as yet, been no adverse results of their use in the food chain. Because of these worries and the mechanisms of politics, agricultural biotechnology has become the target of concerns about food safety (BSE, Foot & Mouth Disease), along with globalisation and the power of multinational companies. These concerns will, hopefully, be overcome by a more open and well-informed dialogue between scientists, opinion leaders, educators and the public. If judiciously applied, genetically modified crops will help increase sustainability and the fight against hunger in the world.

Biotechnology↗

Allergenicity prediction by protein sequence.

Potential allergenicity of transgenic proteins for consumption must be investigated before their introduction into the food chain. A prerequisite is sequence analysis. We have critically reviewed the performance of the current guidelines proposed by the Food and Agriculture Organization (FAO) and the World Health Organization (WHO) for allergenicity prediction based on protein sequence and show that its precision is very low. To improve prediction, we propose a new strategy based on sequence motifs identified from a new allergen database. If tested on random test sequences and known allergens, both methods are apparently very sensitive. However, the precision of our motif-based prediction (95.5%) is superior to the current method (36.6%). We conclude that the proposed motif-based prediction is a superior alternative to the current method for use in the decision-tree approach for allergenicity assessment.

Allergens↗

[Diet as a source of human exposure to polychlorinated dibenzo-P-dioxins (PCDD)].

Dioxins are highly toxic by-products of many industrial processes e.g. chemical and municipal waste incineration or production of chlorophenols. These compounds penetrate the environment via air, water and soil and are then incorporated in food chains. The major source of human exposure (90% of total exposition) is consumption of a wide variety of common foods (meat, fish and dairy products) containing small amounts of dioxins. The average daily intake of PCDD via food was estimated in the range of 1-3 pg/kg bw. Common characteristics of all congeners detected in foodstuffs were 2,3,7,8-chlorine substitution. Commercial milk samples could be contaminated by PCDD/DFs present in the pulp used for the production of the milk cartoon. Also higher levels of these xenobiotics were found in samples from cows grazing in the vicinity of incinerators as compared to samples from rural farms. Human exposure to dioxin begins early in life since breast-feeding is the best way to nourish an infant. The nursing baby in developed countries get a particularly high dose of dioxins (about 85 pg TEQ/kg bw/day). Food contamination with dioxins leads to enhanced accumulation of these compounds in human tissues to the extent of exceeding acceptable level.

Diet↗

Supercritical fluids as alternative, safe, food-processing media: an overview.

The continuous growth of world population and its concentration in the urban areas require food supplies that are continuous, sufficient and of good quality. To resolve this problem techniques have been developed for increasing food quantity and quality. The techniques are applied throughout the food chain from production, conservation and during distribution to the consumers (from "the field to the fork"). During handling of food, chemicals are often deliberately added to achieve improved processing and better quality. This is one of the main reasons food undergoes different kinds of contamination. This overview focuses on the application of supercritical fluids as media for handling food materials during processing with the perspective of reducing chemical contamination of food. Examples of developmental applications of this technique and on research work in process are presented. Emphasis is given to extraction and biotransformation techniques.

Carbon Dioxide↗

Veterinary public health activities aimed at prevention of intoxications by chemical residues in foods of animal origin. Suggestions for inspection programmes.

Practically all today's raw agricultural products have been treated or exposed to one or more agricultural chemicals or veterinary products, in order to increase food production. A tremendous amount of work has been done by veterinarians in coping with diseases and health risks due to microorganisms, parasites and other agents of biological origin. There is no doubt that veterinary services, research and educational institutions have a long and successful tradition also in dealing with problems of chemicals associated with animal and food production, processing, transportation, storage and distribution. Due to the increasing quantity and large numbers of chemicals now used in animal production and related fields, it has however become indispensable to broaden and intensify the education and training of veterinarians, as well as to ensure their participation in all sectors of this field. Veterinarians should be fully involved in the surveillance, prevention and control of intoxications by chemical residues. They are well qualified to do this. They are working continuously in the areas where exposure to animals and food may occur, possess adequate knowledge of the routes of entry of such chemicals into food chains, the fate of their residues, the health hazards involved, as well as of the toxicology, pathology, pathophysiology, and food hygiene and technology. Residues present an enormous challenge for surveillance, prevention and control in agriculture, food processing and related activities.

Animals↗

Occurrence of ochratoxin A in wine and ochratoxigenic mycoflora in grapes and dried vine fruits in South America.

Grape and wine production in South America represents about 6.6% and 10% respectively of the world grape and wine production. The available information on the ochratoxigenic mycoflora and ochratoxin A (OTA) presence in wine grapes, wines, grape juices and dried vine fruits is limited. Surveys have been carried out in Argentina and Brazil which showed that Aspergillus niger aggregate are predominant in the Argentinean varieties while from the Brazilian varieties the species A. niger, Aspergillus ochraceus and Aspergillus carbonarius were isolated. A mycobiota survey from wine grapes in Argentina showed that while Alternaria alternata was predominant, Aspergillus section Nigri species were isolated from 60% of samples. About 41% of black Aspergilli isolates produced OTA with levels ranging from 2 to 24.5 ng mL(-1). In another study, about 83% of A. carbonarius isolates from dried vine fruits produced OTA, with levels ranging from 2 to 5200 ng mL(-1). A survey of grape juices and wines of Brazilian, Argentinean and Chilean origin were found to contain very low levels of OTA. Studies are in progress in Latin America on the ecophysiology of ochratoxigenic fungi and OTA occurrence to reduce the impact of this toxin in the food chain.

Aspergillus↗

[Report on Salmonella isolates submitted to the German National Veterinary Salmonella Reference Laboratory in the year 1999].

The National Salmonella Reference Laboratory (NRL-Salm) of the Federal Institute for Health Protection of Consumers and Veterinary Medicine receives putative Salmonella isolates originating from animals, food, feed and the environment for typing. This report summarises the results of the sero- and phagetyping studies. In livestock S. Typhimurium DT 104 with 24% and S. Enteritidis PT 4 with 9% of all isolations predominate like in the human isolates. These sero- and phagetypes are frequently isolated from food as well and consequently can reach the consumer via the food chain.

Animals↗

Salmonella and the international food trade.

Non-typhoid Salmonella spp. continue to figure prominently in many national epidemiological registries as the leading cause of bacterial foodborne disease. Although Salmonella enterocolitis is generally a self-limiting illness that may require fluid and electrolyte replacement, the disease can spread systemically and degenerate into a chronic condition such as reactive arthritis, osteomyelitis, cardiac inflammation or neural disorders. Ampicillin, chloramphenicol and trimethoprim-sulfamethoxazole have provided the mainstay of therapy for the clinical management of bacteremic salmonellosis. However, the increasing occurrence of strains that are resistant to one or more of these traditional antibacterial drugs has resulted in the wider use of quinolones for the treatment of Salmonella septicaemia. Successful clinical results with these newer drugs are already being overshadowed by the emergence of salmonellae that are resistant to these therapeutic agents. A rapidly growing international trade in agricultural, aquacultural and manufactured food products has greatly facilitated the introduction of new Salmonella serovars within the geographical boundaries of importing countries. This paper reviews the prevalence of Salmonella in selected food types that are subject to the import-export market and attendant epidemiological overtones. More specifically, the importance of fresh fruits and vegetables, spices, cheese, and aquacultural products as vehicles of human infection will be underlined. The potential impact of the widespread use of antibiotics of importance in human medicine in the aquaculture industry will also be discussed. The ubiquitous distribution of Salmonella in the natural environment and its prevalence in the global food chain, the physiological adaptability and virulence of this important human bacterial pathogen, and its potentially serious economic impact on the food industry predicate the need for continued vigilance and stringent controls at all levels of food production.

Animals↗

Detection of metazoan species as a public health issue: simple methods for the validation of food safety and quality.

Species identification represents a critical issue in food chain safety and quality control. Several procedures are available to detect animal proteins in cattle feed or to trace transgenic foods. The most effective approach is based on the use of DNA as a marker. Amplification of DNA provides rapid, sensitive and specific protocols. Several target genes can be used, but new insights come from the mitochondrial genome, which is naturally amplified in each cell and shows a remarkable resistance to degradation. These are key points when analysing complex matrices such as foods, animal feedstuff or environmental samples. Traceability is important to prevent BSE or to monitor novel foods, such as genetically modified organisms. Amplification is commonly performed, but it requires expertise and a molecular biology laboratory to perform restriction analysis, electrophoresis or gel staining for the visualisation of results. Hereby, we consider a strategy based on multiple nested amplification and reverse hybridisation assay that virtually requires only a thermocycler and a water bath. The protocol is rapid and simple and can simultaneously detect different species in a DNA sample. This promising approach allows microarray developments, opening up to further perspectives. An international application has been published under the patent cooperation treaty. Presently, a ban on feeding ruminants on cattle-derived proteins is in force in Europe and USA. The identification of metazoan traces in a sample is not only a mere preventive measure for BSE, but represents a possible screening system for monitoring biotechnology products and procedures, as well as a quality control strategy to assure consumer's rights.

Animals↗

Industrial requirements in food safety.

The principles of establishing industrial requirements in food safety are described, taking risk potentials all along the food chain into their respective account. Regulations will, in the future, lead to increased autocontrol in production. The rapid changes in food technology require constant adaptation to new problems, to keep the global quality of food at a high level. Regulatory authorities will, in the new European market, concentrate on enforcement of 'essential requirements' while industrialists will follow good manufacturing practices. Open dialogue between the latter, the former and the scientific community is highly desirable since mutual knowledge of the problem will help maintain a high level of food safety, for the benefit of everybody.

Europe↗

Identification of model structure for aquatic ecosystems using regionalized sensitivity analysis.

The Regionalized Sensitivity Analysis (RSA) was developed in 1978, for identifying critical unknown processes in poorly defined systems, thus directing the focus of further scientific investigations. Here, we demonstrate its application to model structure identification, by ranking the constituent hypotheses and identifying the critical elements for progressive revision of the model. Our case study is Lake Oglethorpe--a small monomictic impoundment in South-eastern Georgia, USA. Recent studies indicate that the warm temperate regional climate affords an extended growing season--typically from March to October--which promotes bacterial productivity in the lake. The result is a summer food web dominated by microbial processes, in contrast to the conventional phytoplankton-dominated food chains typically observed in the cold temperate lakes of Europe and North America. Starting with a simple phytoplankton-based food web model and a qualitative definition of system behaviour, we use the RSA procedure to establish the critical role of bacteria-mediated decomposition in Lake Oglethorpe, thus justifying the inclusion of microbial processes. Further analysis reveals the importance of size-dependent selective consumption of phytoplankton and bacteria. Finally, we discuss important practical implications of this novel application of the RSA regarding sampling efficiency and statistical robustness.

Animals↗

Shiga toxin producing Escherichia coli infection: current progress & future challenges.

Shiga toxin producing Escherichia coli (STEC) is a newly emerged pathogen that has been the focus of immense international research effort driven by its recognition as a major cause of large scale epidemics and thousands of sporadic cases of gastrointestinal illness. It produces a severe bloody diarrhoea that is clinically distinct from other types of diarrhoeal diseases caused by other enteric pathogens. One of the most important areas of current exploration concerns how STEC enters our food chain, an investigational avenue that begins with the ecology of STEC in animals and in the environment. A variety of foods have been identified as vehicles of STEC-associated illness and this makes the organism one of the most serious threats to the food industry in recent years. The pathogenesis of STEC is multifactorial and involves several levels of interaction between the bacterium and the host. STEC strains carry a set of virulence genes that encode the factors for attachment to host cells, elaboration of effective molecules and production of two different types of Shiga toxins. These genes are found in the locus of enterocyte effacement (LEE), lamboid phages, and a large virulence associated plasmid. The publication of the complete genome sequence of Esch. coli O157:H7 chromosome offers a unique resource that will help to identify additional virulence genes, to develop better methods of strain detection and in the understanding of the evolution of Esch. coli through comparison with the genome of the non-pathogenic laboratory strain Esch. coli K-12. These research efforts in turn, should lead to development of new potent and cost effective anti-Stx therapies or vaccines and thereby major improvement in human health world-wide.

Animals↗

Hospitals and plastics. Dioxin prevention and medical waste incinerators.

CHLORINATED DIOXINS and related compounds are extremely potent toxic substances, producing effects in humans and animals at extremely low doses. Because these compounds are persistent in the environment and accumulate in the food chain, they are now distributed globally, and every member of the human population is exposed to them, primarily through the food supply and mothers' milk. An emerging body of information suggests that dioxin contamination has reached a level that may pose a large-scale, long-term public health risk. Of particular concern are dioxin's effects on reproduction, development, immune system function, and carcinogenesis. Medical waste incineration is a major source of dioxins. Polyvinyl chloride (PVC) plastic, as the dominant source of organically bound chlorine in the medical waste stream, is the primary cause of "iatrogenic" dioxin produced by the incineration of medical wastes. Health professionals have a responsibility to work to reduce dioxin exposure from medical sources. Health care institutions should implement policies to reduce the use of PVC plastics, thus achieving major reductions in medically related dioxin formation.

Bioethics↗

Use of ramification amplification assay for detection of Escherichia coli O157:H7 and other E. coli Shiga toxin-producing strains.

Escherichia coli O157:H7 and other Shiga toxin-producing E. coli (STEC) strains are important human pathogens that are mainly transmitted through the food chain. These pathogens have a low infectious dose and may cause life-threatening illnesses. However, detection of this microorganism in contaminated food or a patient's stool specimens presents a diagnostic challenge because of the low copy number in the sample. Often, a more sensitive nucleic acid amplification method, such as PCR, is required for rapid detection of this microorganism. Ramification amplification (RAM) is a recently introduced isothermal DNA amplification technique that utilizes a circular probe for target detection and achieves exponential amplification through the mechanism of primer extension, strand displacement, and ramification. In this study, we synthesized a circular probe specific for the Shiga toxin 2 gene (stx(2)). Our results showed that as few as 10 copies of stx(2) could be detected, indicating that the RAM assay was as sensitive as conventional PCR. We further tested 33 isolates of E coli O157:H7, STEC, Shigella dysenteriae, and nonpathogenic E. coli by RAM assay. Results showed that all 27 STEC isolates containing the stx(2) gene were identified by RAM assay, while S. dysenteriae and nonpathogenic E. coli isolates were undetected. The RAM results were 100% in concordance with those of PCR. Because of its simplicity and isothermal amplification, the RAM assay could be a useful method for detecting STEC in food and human specimens.

Animals↗

European research on ochratoxin A in grapes and wine.

European wine production represents about 70% of world production and thus is an important export commodity. Ochratoxin A (OTA) was first detected as a wine contaminant in 1996 and the role of Aspergillus section Nigri and A. carbonarius in OTA production discovered in Europe in 1999. Subsequently Europe-wide surveys have shown that A. carbonarius is predominantly responsible for OTA contamination of grapes, wine and vine fruits. Analyses of wine samples throughout Europe have shown that there is a gradient in OTA concentration with a decrease from red, to rose and to white wines. The latitude of production is an important factor in determining risk from OTA contamination. Some geographic regions in Southern Europe are more prone to contamination with the toxigenic species and OTA. Ochratoxin A has also been found in much higher concentrations (max. 53 mug/kg) in dried vine fruit than in wine suggesting that A. carbonarius can dominate the drying vine fruit ecosystem. There is a significant lack of knowledge in Europe on conducive climatic conditions preharvest and their relationship with levels of risk from OTA contamination in grapes and their fate in wine production. This needs to be integrated with cultivation system to maximise the prevention of OTA entering this food chain.

Aspergillus↗

Nutrition surveillance of Ireland.

In summary then we can say that diet in Ireland is changing continuously, that the patterns as documented in diet are consistent with the epidemiological patterns of the major chronic diseases, although predictions for the future will be complex because of both positive and negative changes in diet behaviours. The major influences on diet relate to changes in the food chain, which have been enormous in 100 years; at consumer level, health concerns appear to be one of many considerations in food choices. We need a more consistent, comprehensive database in order to make meaningful inferences about diet and health. Furthermore, to be really useful such databases should include both quantitative and qualitative information.

Diet↗