Genetically engineered foods: implications for food allergy

The products of agricultural biotechnology, including such common foods as corn and soybeans, are already reaching the consumer marketplace. Consumer exposure to such foods is already fairly significant, particularly in the USA. Thus far, no reports exist regarding allergic reactions to the crops that have been approved for introduction into the food supply. These crops have been modified to only a minor extent by comparison with their traditional counterparts, and the level of expression of new and novel proteins is quite low. Thus, consumer exposure to these novel proteins is very low and unlikely to result in allergic sensitization. Nevertheless, foods produced through agricultural biotechnology must be assessed for safety, including their potential allergenicity, before they may be approved by worldwide regulatory agencies for entry into the food supply. However, the adequacy of the current approach to the assessment of the potential allergenicity of foods produced through agricultural biotechnology has been the subject of considerable scientific and regulatory debate.     

Will genetically modified foods be allergenic?

Foods produced through agricultural biotechnology, including such staples as corn, soybeans, canola, and potatoes, are already reaching the consumer marketplace. Agricultural biotechnology offers the promise to produce crops with improved agronomic characteristics (eg, insect resistance, herbicide tolerance, disease resistance, and climatic tolerance) and enhanced consumer benefits (eg, better taste and texture, longer shelf life, and more nutritious). Certainly, the products of agricultural biotechnology should be subjected to a careful and complete safety assessment before commercialization. Because the genetic modification ultimately results in the introduction of new proteins into the food plant, the safety, including the potential allergenicity, of the newly introduced proteins must be assessed. Although most allergens are proteins, only a few of the many proteins found in foods are allergenic under the typical circumstances of exposure. The potential allergenicity of the introduced proteins can be evaluated by focusing on the source of the gene, the sequence homology of the newly introduced protein to known allergens, the expression level of the novel protein in the modified crop, the functional classification of the novel protein, the reactivity of the novel protein with IgE from the serum of individuals with known allergies to the source of the transferred genetic material, and various physicochemical properties of the newly introduced protein, such as heat stability and digestive stability. Few products of agricultural biotechnology (and none of the current products) will involve the transfer of genes from known allergenic sources. Applying such criteria provides reasonable assurance that the newly introduced protein has limited capability to become an allergen.     

Risks of allergic reactions to biotech proteins in foods: perception and reality

In recent years, significant attention has been paid to the use of biotechnology to improve the quality and quantity of the food supply due in part to the projected growth in the world population, plus limited options available for increasing the amount of land under cultivation. Alterations in the food supply induced by classical breeding and selection methods typically involve the movement of large portions of genomic DNA between different plant varieties to obtain the desired trait. This is in contrast to techniques of genetic engineering which allows the selection and transfers specific genes from one species to another. The primary allergy risk to consumers from genetically modified crops may be placed into one of three categories. The first represents the highest risk to the allergic consumer is the transfer of known allergen or cross-reacting allergen into a food crop. The second category, representing an intermediate risk to the consumer, is the potential for replacing the endogenous allergenicity of a genetically-modified crop. The last category involves expression of novel proteins that may become allergens in man and generally represents a relatively low risk to the consumer, although this possibility has received attention of late. In order to mitigate the three categories of potential allergy risk associated with biotech crops, all genes introduced into food crops undergo a series of tests designed to determine if the biotech protein exhibits properties of known food allergens. The result of this risk assessment process to date is that no biotech proteins in foods have been documented to cause allergic reactions. These results indicate that the current assessment process is robust, although as science of allergy and allergens evolves, new information and new technology should help further the assessment process for potential allergenicity.     

Immunochemical detection of egg‐white antigens and allergens in meat products

BACKGROUND: The purpose of this study was to detect antigens and allergens in egg-white byproduct ingredients and after their incorporation in processed pork meat pastes. Commercially prepared foods may have potentially allergenic ingredients (egg, milk, soybean, wheat, and peanut) added in processing. Since allergic patients may react to unidentified ingredients, it is important to assess the allergenic potency of these food proteins added during processing. Egg white was chosen as an experimental model, since egg is one of the most prevalent allergens in food hypersensitivity. METHODS: Experimental pork meat pastes containing egg white underwent pasteurization and sterilization. Ingredients derived from egg-white or paste extracts were isoelectrofocused and then blotted onto cyanogen bromide-activated nitrocellulose membranes. Egg-white antigens were identified in ingredients and in meat products with rabbit anti-egg-white antiserum by isoelectric focusing immunoblotting. Allergens were identified with sera from sensitized patients. A sensitive ELISA test was developed to detect egg-white proteins in raw, pasteurized, and sterilized meat products. RESULTS: Antigens and allergens in four egg-white byproducts were detected. Egg-white antigens were detectable in all ingredients and meat pastes by ELISA. Allergens were detected in ingredients and in raw and pasteurized products by immunoprint techniques and ELISA. CONCLUSIONS: Masked egg-white allergens are recognized by human serum IgE after pasteurization. Egg-white antigens are detectable in sterilized meat by ELISA techniques. Ingestion of processed foods could entail a risk of allergic reactions for sensitized consumers.     

Ingredient and labeling issues associated with allergenic foods

Foods contain a wide range of food ingredients that serve numerous technical functions. Per capita consumer exposure to most of these food ingredients is rather low with a few notable exceptions such as sugar and starch. Some food ingredients including edible oils, hydrolyzed proteins, lecithin, starch, lactose, flavors and gelatin may, at least in some products, be derived from sources commonly involved in IgE-mediated food allergies. These ingredients should be avoided by consumers with allergies to the source material if the ingredient contains detectable protein residues. Other food ingredients, including starch, malt, alcohol and vinegar, may be derived in some cases from wheat, rye or barley, the grains that are implicated in the causation of celiac disease. If these ingredients contain gluten residues, then they should be avoided by celiac sufferers. A few food ingredients are capable of eliciting allergic sensitization, although these ingredients would be classified as rarely allergenic. These ingredients include carmine, cochineal extract, annatto, tragacanth gum and papain. Food manufacturers should declare the presence of allergenic food ingredients in the ingredient listings on product labels so that allergic consumers can know to avoid these potentially hazardous products.     

Optimization of electrophoresis for the identification of low molecular mass allergens in hazelnuts.

Conventional electrophoresis techniques used to identify food allergens are insufficient to separate low molecular mass proteins and peptides. In this paper we performed three different methods which provided an extended resolving power for small proteins. Applying the improved techniques, we were able to separate hazelnut proteins into distinct bands below 10 kDa.     

Genetic modification and plant food allergens: risks and benefits.

Plant genetic engineering has the potential to both introduce new allergenic proteins into foods and remove established allergens. A number of allergenic plant proteins have been characterized, showing that many are related to proteins which have potentially valuable properties for use in nutritional enhancement, food processing and crop protection. It is therefore important to monitor the allergenic potential of proteins used for plant genetic engineering and major biotechnology companies have established systems for this. Current technology allows gene expression to be down-regulated using antisense or co-suppression and future developments may allow targeted gene mutation or gene replacement. However, the application of this technology may be limited at least in the short term by the presence of multiple allergens and their contribution to food processing or other properties. Furthermore, the long-term stability of these systems needs to be established as reversion could have serious consequences.     

Biological component of the NIMH clinical research branch collaborative program on the psychobiology of depression: II. Methodology and data analysis

A preceding paper has reviewed the history, background, and rationale for this collaborative effort exploring the biologic basis of the affective disorders. This paper details the "flow" of a subject through the experimental protocol, the instrumentation used to obtain the clinical and behavioural data, and the biologic methodologies employed in the analysis of the body fluids. Data management and analysis techniques developed for this study are also examined.     

A perspective on the biotechnological potential of microalgae

Microalgae are the untapped resource with more than 25,000 species of which only 15 are in use. In recent years, microalgal culture technology is a business oriented line owing to their different practical applications. Innovative processes and products have been introduced in microalgal biotechnology to produce vitamins, proteins, cosmetics, and health foods. For most of these applications, the market is still developing and the biotechnological use of microalgae will extend into new areas. With the development of sophisticated culture and screening techniques, microalgal biotechnology can meet the challenging demands of both the food and pharmaceutical industries. Genetic improvement should also play an important role in the future development of algal industries. Based on the preliminary research, several therapeutic benefits have been claimed for commercially produced microalgae including AIDS, cancer, and Cerebro vascular diseases. In near future, algal biomass will serve as a renewable energy source through commercial production of hydrocarbon by Botryococcus throughout the world.     

Analysis of food proteins for verification of contamination or mislabelling

Discrepancies between food content and label can lead to adverse reactions in people with hypersensitivity to particular food components. Over a 3‐year period, 20 occasions arose in Sweden where discrepancies between label and content were confirmed. In 14 cases the investigation was initiated because of adverse reactions observed by individuals with known disease. Analysis of the offending food included qualitative and quantitative antibody‐based techniques. The unexpected food ingredients were hazelnut, peanut, egg, milk, wheat, soy and chicken protein. The offending foods were chocolate, ice cream, meringue, lollypop, meatballs, sausage, hamburger, ham, kebabs, buns, pasta and buckwheat flour. Our study showed that simple immunological methods can be used for analysis of food protein for verification of contamination or mislabelling.     

Antigenicity of legume proteins

In the food and feed industry, large amounts of agro‐industrial basic materials are used for the formulation of end‐products meant for human or animal nutrition. These basic ingredients and the final end‐products often have to fulfil special requirements regarding nutritional and anti‐nutritional factors (ANFs). A special need therefore exists for the identification and characterization of these factors. As there is increasing interest in the use of legume seeds as protein and energy sources in various foods and feedstuffs, a number of methods for the immunochemical detection and quantification of proteinaceous ANFs in legumes have been developed. Current knowledge of the immunochemical detection and analysis of antigenic proteins in legume seeds and some of the phenomena of these proteinaceous ANFs in young animals are described in this paper.     

The analytical environmental immunochemical consortium

The Analytical Environmental Immunochemical Consortium (AEIC) is a relatively new organization, established with the aim of promoting the use of immunochemical methods as recognized analytical tools for food and environmental testing. The members of AEIC include immunoassay kit manufacturers, agricultural and basic chemical manufacturers, immunoassay equipment manufacturers and commercial, government and academic laboratories involved in the research and development of non‐clinical immunochemical technology.     

Development of Plastic Microfluidic Devices for Sample Preparation

Microfluidics technology shows excellent potential for applications in biotechnology, chemical sensing, and drug delivery. The use of microfluidics results in cycle time reduction, reagent cost and labor intensity savings due to the benefits of miniaturization, and functional integration. As a result, miniature DNA sample preparation and analytical devices may potentially become part of a point-of-care systems for rapid medical diagnoses. Similar diagnostic devices will benefit veterinary and food safety applications. In this paper, we discuss design, fabrication, and testing of plastic microfluidic devices for on-chip genetic sample preparation. These fabrication methods are being used to produce components of a complete genetic sample preparation micro-system. The detailed discussion on the development of micro-PCR (polymerase chain reaction) devices and bio-channel hybridization arrays is given. We also describe a path to further individual component integration.     

Antibody‐based analytical methods for meat species determination and detecting adulteration of milk

The food industry must provide consumers with products which are innocuous, genuine, desirable and nutritive. To assure consumers that food has these characteristics, it is convenient to have appropriate controls of their hygiene state and to detect fraudulent practices, both of which are possible using adequate analytical techniques. However, the analysis of food has its own limitations such as specificity, reproducibility, sensitivity, economy, ease of use and standardization. Immunological techniques have objective advantages which merit their development and further use in the food industry. It has been widely demonstrated that immunological methods can be used in the food industry as reliable analytical techniques. Antibody‐based analytical methods for determining meat species and detecting adulteration of milk have been developed. We review the efforts made to develop immunological reactions and techniques to detect fraudulent replacements of foods. The selection of antigens as immunogens, the development of various polyclonal and monoclonal antibodies, and the selection of immunological techniques from immunodiffusion and immunoelectrophoresis to ELISA are described. The development of recombinant antibodies as an alternative for replacement or substitution of previously developed polyclonal or monoclonal antibody reagents will also be considered.     

Plant biopharming of monoclonal antibodies

Recent advances in molecular biology and plant biotechnology have shifted the concept of growing crops as a food source to serving as a bioreactor for the production of therapeutic recombinant proteins. Plants are potential biopharming factories because they are capable of producing unlimited numbers and amounts of recombinant proteins safely and inexpensively. In the last two decades, plant production systems have been developed for monoclonal antibody production, which has been useful in passive immunization of viral or bacterial diseases. Recently, a recombinant monoclonal antibody for rabies prophylaxis was produced in transgenic plants. Rabies virus epidemics remain still problematic throughout the world, and adequate treatment has been hampered by the worldwide shortage and high cost of prophylactic antibodies such as HRIG. Successful mass production of this monoclonal antibody in plants might help to overcome these problems. An effective plant production system for recombinant biologicals requires the appropriate heterologous plant expression system, the optimal combination of gene expression regulatory elements, control of post-translational processing of recombinant products, and efficient purification methods for product recovery. This review discusses recent biotechnology developments for plant-derived monoclonal antibodies and discusses these products as a promising approach to rabies prophylaxis and the consequence for global health benefits.     

Psychiatric agriculture: systemic nutritional modification and mental health in the developing world

Modernization of agricultural systems to increase output causes changes to the nutritional content of food entire populations consume. Human nutritional needs differ from their "food", thus producing healthy agricultural products is not equivalent to providing agricultural products that are healthy for humans. Inclusion of the food production system as a factor in the increase of neuropsychiatric disorders and other chronic diseases helps explain negative trends in modern chronic diseases that remain unchecked despite stunning advances in modern medicine. Diseases in which our own technology plays a significant role include obesity and resulting disorders, such as diabetes, heart disease, hypertension, stroke and arthritis. Modernization's lure leads to importation of modern agricultural practices into a nutritionally vulnerable, malnourished and sometimes starving developing world. Wealthier nations hedge their food portfolio by having access to a wider variety of foods. The developing world's reliance on staple foods means even a minor widespread nutritional modification of one key food can have profound effects. New agricultural techniques may improve or exacerbate neuropsychiatric disorders through nutritional modification in regions where populations walk a nutritional tightrope with little margin for error. In most of the developing world western psychiatric interventions have failed to make inroads. People's consumption of fish has a demonstrated beneficial effect on their mental health and the omega-3 fatty acid content is a significant factor. Epidemiological, biological and agricultural studies implicate a lack of dietary omega-3s as a factor in certain mental disorders. Replenishing omega-3s has improved mental illnesses in controlled clinical trials. This article's detailed tilapia fish-farming model demonstrates how aquaculture/agriculture techniques can function as a public health intervention by increasing dietary omega-3s through creation of sustainable, economical and culturally appropriate food sources for the developing world.     

Physical methods for the study of the dynamics of axonal transport

Currently used techniques for the study of the dynamics of axonal transport are reviewed. Emphasis is placed on those nonstructural and nonbiochemical methods which are most useful in the investigation of the dynamics of the mechanisms that underline the transport process. The methods by which the transport of specified materials may be assessed are divided into two broad groups: those which involve the collection, or accumulation, of transported materials at a region where transport is slowed or arrested, and those methods in which the distribution of a marker of the transported material is assayed in a series of nerve segments. Potential problems and sources of error associated with these techniques are considered as is their applicability to particular biological preparations. Recently introduced methods for concentrating and labeling transported material are described. New methods for conducting segment analysis of transported material by the use of position-sensitive detectors of radiation are considered. Optical methods of detecting axonal transport are reviewed with emphasis being placed on recently introduced methods and on the means by which the motion of optically detected organelles may be analyzed. In addition, biological preparations which are particularly suited to the optical approach are described.     

High-Pressure Biotechnology in Medicine and Pharmaceutical Science

High-pressure (HP) biotechnology is an emerging techniqueinitially applied for food processing and more recently in pharmaceutical and medical sciences. Pressure can stabilize enzymes and modulate both their activity and specificity. HP engineering of proteins may be used for enzyme-catalyzed synthesis of fine chemicals, pharmaceuticals, and production ofmodified proteins of medical or pharmaceutical interest. HP inactivation of biological agents is expected to be applicable to sterilization of fragile biopharmaceuticals, or medical compounds. The enhanced immunogenicity of some pressure-killed bacteria and viruses could be applied for making new vaccines. Finally, storage at subzero temperatures without freezing is another potential application of HP for cells, animal tissues, blood cells, organs for transplant, and so forth.     

Immunological identification and characterization of individual food allergens.

Food allergies of type-I-allergy are immunoglobulin E (IgE) mediated and caused by certain proteins or glycoproteins, which are called food allergens. An analytical marker of allergens is the IgE-reactivity to these substances. Normally food allergens are minor components in allergenic source material, which consist of a huge number of chemical different substances. Thus allergen extraction, separation and immunological detection methods are described which identify and characterize individual food allergens by a minimum of manipulation. Favoured separation methods of allergenic extracts are electrophoretic ones allowing the combination of highly resolved protein separations with immunological detection methods subsumed by the term immunoblotting. These techniques are a useful basis to characterize allergens by chemical methods. Once the primary protein structure of a food allergen is established, the way is cleared for the identification of epitopes. Epitopes are immunological detectable parts of a protein or glycoprotein generating the interface between chemical structure and immune-system. The nature of epitopes may differ, for instance, can be conformational, continuous, or built up by glycoconjugates, which determine the stability of food allergens, especially in the case of food processing. Progress in identification and characterization of food allergens will improve diagnostics and therapy of food allergy.     

Debated agronomy: public discourse and the future of biotechnology policy in Ghana

This paper examines the highly contested and ongoing biotechnology (Bt) policy-making process in Ghana. We analyse media content on how Bt is viewed in the context of Ghana’s parliamentary debate on the Plant Breeders Bill and within the broader public policy-making literature. This paper does not seek to take a position on Bt or the Bill, but to understand how policy actors influence the debate with political and scientific rhetoric in Ghana. The study reveals that in the midst of scientific uncertainties of Bt’s potential for sustainable agriculture production and food security, policy decisions that encourage its future adoption are heavily influenced by health, scientific, economic, environmental and political factors dictated by different ideologies, values and norms. While locally pioneered plant breeding is visible and common in the Ghanaian food chain, plant breeding/GMOs/Bt from international corporations is strongly resisted by anti-GMO coalitions. Understanding the complex and messy nature of Bt policy-making is critical for future development of agricultural technology in Ghana and elsewhere.