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PubMed2004

Vaccination against salmonella, enterohaemorrhagic E. coli and Campylobacter in food-producing animals.

The threat of zoonotic infection with food-poisoning enteric pathogens remains a major threat to public health throughout the world. Control of enteric pathogens within food-producing animals remains an obvious strategy to prevent the introduction of these pathogens into the human food chain. Vaccines are currently available for the control of Salmonella; however such vaccines vary in their efficacy and acceptability to the food production industries and consumers. Vaccines for the control of enterohaemorrhagic E. coli and Campylobacter are currently unavailable. Understanding the molecular basis of how these organisms colonise the intestines and cause disease is essential for the development of effective multivalent vaccines. The mechanisms by which these organisms colonise the gut will be reviewed. Bacterial Type Three Secretion Systems (TTSS) have been shown to be major virulence factors influencing the colonisation and pathogenicity of Salmonella and enterohaemorrhagic E. coli in some but not all animal species. Thus, understanding the specific nature of host/pathogen interactions is crucial in the development of cross-species vaccines. TTSSs act by delivering effector proteins into intestinal epithelial cells, which act to modify signalling events in host cells causing cytoskeletal and pathophysiological changes to the benefit of the pathogen. Disruption of TTSSs and/or related secreted effector proteins can be adopted as a strategy for the attenuation of live vaccine strains. Furthermore secreted effector proteins have the potential to be incorporated into sub-unit vaccines. As many of such effector proteins are conserved between different serotypes, such vaccines offer the hope of cross-serotype protective immune responses. Novel experimental vaccines are currently being developed to exploit these and other recent discoveries in bacterial virulence mechanisms. The potential of such vaccines to control zoonotic pathogens will be discussed.

Animals↗
PubMed2003

[The improvement of the animal health risk analysis system in France].

After several decades of gradual improvement in its system for managing health risks, France was confronted in 1996 with the bovine spongiform encephalopathy crisis. This triggered a collective questioning, which highlighted the need to reform a system that had shown its limitations. Risk analysis, established as a key principle by the Agreement on the Application of Sanitary and Phytosanitary Measures (SPS Agreement) of the World Trade Organization (WTO), was cast as the necessary basis of the reform, objectives of which were to better identify priority risks in order to ensure the protection of human and animal health, and to improve the quality of measures implemented by the public authorities. The Act of 1 July 1998 founded several independent risk assessment agencies, including the French Agency for Food Safety (AFSSA), with the specific mandate of food safety at every stage of the food chain. Other organisational reforms enhanced the new system, notably the separation between the functions of risk management and economic support for food industries, initially at central level, then in 2002 at the level of field services in the 100 French départements. Lastly, new procedures were introduced. These were designed, in accordance with the principles of risk assessment, to better identify and to individualise the different decision-making sequences. The decision-making process was extended to include submission to the agency in charge of evaluating health risks and examination by the agency of the resulting draft decision.

Animal Welfare↗
PubMed2006

[The microbiological safety of food products, and environmental factors].

The author of the review analyzes the mechanisms of changes of biological properties of microorganisms causing alimentary infections and intoxications. A complex of environmental factors, such as anthropogenic, technogenic, social, ecological, and climatic ones, are considered to be the main cause of these changes. Food contamination by microorganisms and their toxins is facilitated by climatic warming. The exposure of consumers to food toxins grows, and alimentary infections become more frequent. New classes of alimentary infections have appeared; clinical manifestations and complications of food-related infections have become more serious. Besides, the quality and value of food products may be reduced by lactic acid microorganisms and moulds, whose content in food chains increases due to warming, especially in regions with a high anthropogenic load. From the economic perspective, the behavior of microbial food contaminants under the conditions of climatic warming increase direct losses of agricultural products due to their lesion by microscopic fungi, mycotoxins etc., as well as spoilage microflora. This may result in food shortage and famine in distant regions. The article covers control measures and the management of microbiological risks under the condition of climatic warming.

Environmental Exposure↗
PubMed1993

Soil invertebrate/micro-invertebrate interactions: disproportionate effects of species on food web structure and function.

The preservation of biodiversity requires an appreciation of food web structure and an understanding of how disturbance alters their structure and function. Theoretical and empirical studies of food webs demonstrate that food webs possess a regular structure. Food chain length appears limited to three to four transfers, and, complexity and diversity are constrained. When ecosystem energetics are considered, species within food webs are seen to form interactive assemblages that process matter at different rates and respond to disturbance differently. Disturbance may affect the diversity of a system, or, may influence the relative importance of one species assemblage over another. Moreover, predicting the impact of disturbance on a system is difficult as species that comprise and process a small fraction of the system's biomass may control a disproportionate fraction of the system's biomass and diversity. Seven food webs at four sites were used in a modeling exercise to demonstrate this point. Field studies involving the role of mycorrhizal fungi yielded results consistent with the modeling studies as the types of plant species present, the level of production and the diversity of production were related to the levels of mycorrhizal fungi in the soils following disturbance. The results indicate that all species are important to ecosystem structure and function and that the monitoring of ecosystems and conservation efforts should expand their emphasis to the preservation of ecosystem integrity as well as that of individual species.

Animals↗
PubMed2001

Thermal inactivation of antimicrobial-resistant Gram-positive cocci in chicken meat: D and Z value determinations.

Antimicrobial-resistance in Gram-positive bacteria is reported with increasing frequency in strains isolated from food animals. Their isolation from commercial poultry carcasses and meat products constitute a potential risk that resistant strains or resistance genes might spread to humans via the food chain. As bacterial inactivation by thermal process is a critical control point in the safe preparation of many ready-to-eat foods, it is important to determine the thermal resistance of these organisms. The present study was undertaken to investigate the thermal tolerance (D and Z values) of antimicrobial-resistant, Gram-positive cocci in ground chicken meat. The antimicrobial-resistant, Gram-positive cocci for this study were isolated from two poultry processing plants in Western Australia. D and Z value data indicate that these isolates do not exhibit enhanced thermal resistant characteristics. The estimated lethal effect of the cooking process for chicken meat indicates that an internal temperature of 70 degrees C for 2.1 min would provide a 7-log reduction of all cell suspensions tested.

Animals↗
PubMed2006

Stress response of Campylobacter spp. and its role in food processing.

In many temperate countries Campylobacter spp. are the most common bacterial causes of human infectious intestinal disease. Yet the aetiology of this infection has only partly been described. A majority of human campylobacteriosis cases are associated with food of animal origin. Despite being very sensitive to environmental stressors Campylobacter spp. are able to persist in the food chain and can pose a threat to the consumer. In this review, the survival potential and stress response of Campylobacter spp. in food will be summarized and the importance of food preservation technologies will be discussed.

Adaptation, Physiological↗
PubMed2005

Discrimination of Aspergillus niger and other Aspergillus species belonging to section Nigri by PCR assays.

Aspergillus species included in section Nigri are common in plant products and processed food, such as grapes, cereals, coffee and derivatives, particularly in warm and tropical climates. Two of these species, A. carbonarius and A. niger, are known to produce ochratoxin A (OTA), a potent nephrotoxin and carcinogenic to human (group 2B). Recognition of the several species of this section is difficult and requires considerable expertise using conventional methods based on morphological features. In this work we describe rapid, sensitive and robust assays based on the PCR technique to discriminate the main species included in section Nigri: A. japonicus, A. heteromorphus, A. ellipticus and the two morphologically indistinguishable species of the A. niger aggregate: A. niger and A. tubingensis. The species-specific primers have been designed on the basis of ITS (internal transcribed spacers of rDNA units) sequence comparisons obtained from several Aspergillus strains and have been tested in a number of strains from different origins and hosts. These PCR assays, based on multi-copy sequences, are highly sensitive and specific and represent a good tool for an early detection of OTA-producing Aspergillus species in order to prevent OTA from entering the food chain.

Aspergillus↗
PubMed1999

Spread of antibiotic resistance with food-borne pathogens.

This short review summarizes data on antibiotic resistance profiles of common food-borne pathogens like Salmonella sp., Escherichia coli, Campylobacter sp., Listeria monocytogenes, Clostridium perfringens, Staphylococcus aureus, and coagulase-negative staphylococci. As a flashlight on the literature of the last few years, it provides ample evidence that antibiotic resistance traits have entered the microflora of farm animals and the food produced from them. Molecular analysis of the resistance genes, where available, shows that the food microflora is not separated from its human counterpart and conjugative transfer of resistance genes has been demonstrated in vitro and in a few cases in vivo. For example, for Salmonella typhimurium, resistance towards tetracyclines has increased from zero in 1948 to a 98% level in certain epidemic populations of S. typhimurium DT104 in 1998. The high incidence of food-borne pathogens in raw meat and milk together with a high level of therapeutic, prophylactic and nutritional application of antibiotics in agriculture reveals an antibiotic resistance problem of global dimensions. The resistance problem in human medicine will not be solved if there is a constant influx of resistance genes into the human microflora via the food chain.

Animals↗
PubMed2005

Determination of total aerobic and indicator bacteria on some raw eaten vegetables from wholesalers in Ankara, Turkey.

The aim of this study was to investigate the bacteriological quality of some raw eaten salad vegetables obtained from wholesalers in Ankara, Turkey. A total of 180 samples including lettuces, cos lettuce, iceberg lettuce, parsley, dill and carrots were analyzed for total aerobic bacteria, total coliform bacteria and E. coli between January 2004 and April 2004. Compact Dry media (Nissui Pharmaceutical Co. Ltd., Japan) were used for bacteriological analysis. Outer leaves of lettuce, cos lettuce and iceberg-lettuce samples had higher bacterial loads (3.3-7.4 log(10)CFU(-1)) than inner leaves. Neither total aerobic and coliform bacteria nor E .coli were isolated from seven inner leaves (two cos and five iceberg-lettuce samples). E. coli was significantly more often detected on parsley (21/30) and dill samples (12/30) (p<0.05). Consequently, we showed that fresh salad vegetables (especially parsley, dill and cos lettuce) might contain pathogenic microorganisms and represent a risk for consumers regarding foodborne disease. The importance of adequate measures throughout the farm-to-table food chain was emphasized.

Colony Count, Microbial↗
PubMedDate not supplied

Identification of Albizia gum exudates which are not permitted food additives.

Trees of the genus Albizia have frequently been confused with Acacia species. The genus Albizia has been recommended for more extensive arid zone development; its species are sources of tannins and gum exudates, which are not included in any of the regulatory lists of permitted food additives. Analytical data permitting their identification are therefore required to allow food law compliance to be monitored. This paper presents data which serve to characterize the gums from seven Albizia species, making a total of eleven Albizia species for which data are available. The presence of tannins, and high proportions of aluminium and heavy metals, indicates that gum importers and food processors must be vigilant to ensure that Albizia gums do not enter human food chains as adulterants or contaminants.

Amino Acids↗
PubMed2003

Food poisoning associated with biotoxins in fish and shellfish.

PURPOSE OF REVIEW: In recent times the number of blooms of algae that produce toxins has increased in frequency, intensity and geographical distribution. This review describes some of the illnesses caused by fish and shellfish contaminated with toxins produced by marine algae and by bacteria. RECENT FINDINGS: The increase in toxic algal blooms may be a result of increased awareness, aquaculture, eutrophication, or transport of cysts in ship ballast. Improved chemical methods for the detection of algal toxins are now being developed, and so the number of toxins recognized is increasing. Toxicological data on some of these algal toxins are lacking. Despite the increase in occurrence of algal toxins, scombrotoxic poisoning remains the most common cause of food poisoning associated with the consumption of fish and shellfish. This may be real or it may be a reflection of lack of suitable tests for algal toxins or under-recognition by workers in health care. SUMMARY: The major problem worldwide in this field is the lack of pure toxins for use in developing and standardizing chemical methods for toxin detection. Such methods would permit increased testing of both food and clinical specimens, and hence would prevent the entry of toxic food into the food chain and increase laboratory confirmation of incidents of illness.

Animals↗
PubMed2005

PCR detection assays for the ochratoxin-producing Aspergillus carbonarius and Aspergillus ochraceus species.

Two PCR assays have been developed to detect Aspergillus carbonarius and Aspergillus ochraceus, considered the main sources of ochratoxin A (OTA) contaminating commodities, particularly grapes, coffee and derivatives, in warm climates. The species specific primers have been designed on the basis of ITS (internal transcribed spacers of rDNA units) sequence comparisons obtained from Aspergillus strains and have been tested in a number of strains from different origins and hosts. These PCR assays, based on multi-copy sequences, are highly sensitive and specific and represent a good tool for an early detection of OTA-producing Aspergillus species and to prevent OTA entering the food chain.

Aspergillus↗
PubMed2000

The role of algae (Isochrysis galbana) enrichment on the bioaccumulation of benzo[a]pyrene and its effects on the blue mussel Mytilus edulis.

The role of algal concentration in the transfer of organic contaminants in a food chain has been studied using the ubiquitous model polycyclic aromatic hydrocarbon benzo[a]pyrene (BaP) as the contaminant, Isochrysis galbana as the phytoplankton food source, and the common mussel (Mytilus edulis) as the primary consumer. The effect of algal concentration on BaP uptake by M. edulis was determined by feeding M. edulis daily with I. galbana which had previously been kept in the presence of BaP for 24 h. Four combinations of concentrations of algae and BaP were used to give final exposure concentrations of 30,000 or 150,000 algal cells ml(-1) in combination with either 2 or 50 microg BaP l(-1). BaP concentrations were determined fluorometrically in rest tissues (excluding digestive glands) and digestive gland microsomal fractions of M. edulis after 1, 7 and 15 days exposure, and also in isolated algae. Potentially toxic effects of BaP on M. edulis were examined in terms of blood cell lysosomal membrane damage (neutral red dye retention assay) and induction of digestive gland microsomal mixed-function oxygenase (MFO) parameters [BaP hydroxylase (BPH) and NADPH-cytochrome c (P450) reductase activities]. BaP bioaccumulation in rest tissues (and to a lesser extent in digestive gland microsomes) of M. edulis increased with both increasing BaP and algal exposure concentrations, and over time, producing maximal bioconcentration factors in rest tissues after 15 days exposure to 150,000 algal cells ml(-1) and 50 microg BaP l(-1) of 250,000. The five-fold higher concentration of algae increased BaP bioaccumulation by a factor of approximately 2 for 50 microg BaP l(-1) at day 15. Blood cell neutral red dye retention time decreased linearly with increasing log(10) tissue BaP body burden, indicating an increased biological impact on M. edulis with increasing BaP exposure possibly due to a direct effect of BaP on blood cell lysosomal membrane integrity. An increase was seen in NADPH-cytochrome c reductase activity, and indicated in BPH activity, with 1 but not 7 or 15 days exposure to BaP, indicating a transient response of the digestive gland microsomal MFO system to BaP exposure.

Journal Article↗
PubMed1999

Retention level of Cs-137 and K-40 in some users of an Egyptian nuclear research center.

Body burden activities of Cs-137 and K-40 of about 120 humans, of composite sex, were measured using Inshas whole body counter facilities. The contained body burden activity in such distribution is found to be 3.5-10 Bq l-1 for Cs-137 and 3.39 x 10(-3) kg l-1 as well as 3.69 x 10(-3) kg l-1 for K-40 respectively for females and males. It was found, that the amount of Cs Kg l-1 K increases significantly with increase of either the body volumes and/or the total body potassium. It seemed reasonably to conjecture that, from the results of this study, the retention time of Cs-137 in body is closely connected to the amount of K-40. The discrimination factor related to the body burden content of Cs-137 to K-40 is also experimentally predicted. Moreover, the burden activities of Cs-137 and K-40 over a period of two years are scanned monthly. The results show a slight continuous increase in body burden activity of both elements. The net daily intakes of Cs-137 and K-40 are calculated using a formula developed from ICRP. The calculated results for K-40 show a variation ranging from 30 to 40 Bq per day for females and from 45 to 55 B per day for males. While for Cs-137 show a slight variation ranged from 5.2 to 6.8 Bq per day for a composite sex. The authors emphasise the importance of the periodic measurement of human population since both the consumed food chain and the environmental enclosure contained both radio elements. Accumulation of the daily ingested activity of Cs-137 and K-40, and of food eaten, showed that the predicted body burden retained activity is relatively higher by a range of 5-25% for Cs-137 and 3-15% for K-40 when compared with that detected by the whole body counter over the 24-month scanning course.

Adult↗
PubMed2002

[Food-borne infections: do we need further data collection for public health action and research].

The data needed for controlling and preventing food-borne infectious diseases relied so far on surveillance of the main food-borne infections (Salmonella and listeria infections) to follow trends over time and detect outbreak. However, this systematic continuous data collection was not always sensitive enough to timely detect community outbreaks and did not take into account sporadic cases of food-borne infections which represent the majority of patients (such as Campylobacter infection for example). Therefore, the true burden of food-borne infections, including morbidity, mortality and the social and economic cost could not be assessed. As the issue of food-borne infections got more social attention, the need of further epidemiological data has increased including the implementation of large population studies (active surveillance and follow up studies) associated with analytical studies in the United States (Foodnet) and in some European countries (United Kingdom, The Netherlands, Denmark.). Meanwhile surveillance and detection of outbreaks have substantially improved through the use of new typing scheme, particularly those based on molecular techniques. Their routine use, now, allows an early identification of the clonal spread of food-borne bacteria. The application of automatic detection algorithm to surveillance data base has also improved the performance of outbreak detection and changes of trends. Furthermore, food-borne infection surveillance has become European which allows, by pooling of national database, to identify emergence that did not get noticed in any country. To foster the prevention of sporadic cases, the use of analytical epidemiology has become more and more frequent and has improved the knowledge of food vehicles and risk factors. The risk assessment approach has also been applied to the microbial contamination of food to answer to the increasing needs of expertise, particularly at the international level. This approach, however, needs further methodological development and the collection of extra information on the food chain. Last, but not the least, a wider public health research approach must also be considered, particularly on the social perception of food-borne risks and the cost-effectiveness analysis of the prevention measures that are taken.

Adult↗
PubMed2005

Relevant aspects of Arcobacter spp. as potential foodborne pathogen.

Arcobacter species are Gram-negative spiral-shaped organisms belonging to the family Campylobacteraceae that can grow microaerobically or aerobically. The Arcobacter organisms also have the ability to grow at 15 degrees C, which is a distinctive feature that differentiates Arcobacter species from Campylobacter species. Cultural detection of Arcobacter is generally performed by an enrichment step and takes 4 to 5 days. In the last few years, several studies comparing different culture-based protocols have been published. Furthermore, DNA-based assays have also been established for rapid and specific identification of Arcobacter spp. Recent evidence suggests that Arcobacter, especially A. Butzleri, may be involved in human enteric diseases. Moreover, A. butzleri has also occasionally been found in cases of human extraintestinal diseases. However, up to now, little is known about the mechanisms of pathogenicity or potential virulence factors of Arcobacter spp. There is evidence that livestock animals may be a significant reservoir of Arcobacter spp. and over the last few years, the presence of these organisms in raw meat products as well as in surface and ground water has received increasing attention. In view of control measures to be used to prevent or to eliminate the hazard of Arcobacter spp. in food, several treatments have been evaluated for their effectiveness. While the role of Arcobacter spp. in human disease awaits further evaluation, a precautionary approach is advisable. Measures aimed at reduction or eradication of Arcobacter from the human food chain should be encouraged. With this article, we review the recent literature on this organism with a special emphasis on the information relevant to food safety.

Animals↗
PubMed2000

Microbiological risk assessment in Europe: the next decade.

Under the Agreement on the Application of Sanitary and Phytosanitary Measures that came into force in 1995, it was stipulated that all World Trade Organisation (WTO) members are required to ensure that their sanitary and phytosanitary measures are based on assessment of the risks to human, animal or plant life or health. In doing so, they must take into account risk assessment techniques developed by relevant international organisations. WHO and FAO are two such international organisations that are of very high standard and influence. Their executive body, the Codex Alimentarius Commission has developed the concept of Microbiological Risk Assessment (MRA) in a wider framework called Risk Analysis. The aim of Risk Analysis is to provide a global standard for the interpretation of the acceptability of risks associated to foods to which consumers might be exposed. Microbiological Risk Assessment is an essential element of Risk Analysis because it specifies risks related to pathogenic micro-organisms in the food chain on the basis of sound science, combining qualitative and quantitative data in the areas of epidemiology and pathogenicity of micro-organisms with food production and handling. The concept is still in its infancy but is gaining wide acceptance globally. This paper will describe an inventory of MRA developments in Europe carried out under auspicion of the European Commission. It also gives the results of a literature survey concerning scientific publications on the topic MRA in which the activities in Europe are compared to those elsewhere.

Animals↗
PubMed2004

[Advances in the research of genetic engineering of heavy metal resistance and accumulation in plants].

Using plants to remove or inactivate heavy metal pollutants from soils and surface waters provide a cheap and sustainable approach of Phytoremediation. However, field trials suggested that the efficiency of contaminant removal using natural hyperaccumulators is insufficient, due to that many of these species are slow growing and produce little shoot biomass. These factors severely constrain their potential for large-scale decontamination of polluted soils. Moreover, both the micronutrient and toxic metal content accumulated in crops determine the quality and safety of our food-chain. By a transgenic approach, the introduction of novel genes responsible for hyperaccumulating phenotype into high biomass plants and/or stable crops uptaking minerals as food is a promising strategy for the development of effective techniques of phytoremediation and improvement of nutritional value of stable food through a viable commercialization. Recently, the progress at molecular level for heavy metal uptaking, detoxification and hyperaccumulation in plants, and also the clarification of some functional genes in bacteria, yeasts, plants and animals, have advanced the research on genetic engineering plants of heavy metal resistance and accumulation, and on the functional genes (e . g. gsh1, MerA and ArsC) and their genetic transformated plants. These studies demonstrated commercialization potentials of phytoremediation. In this paper, the molecular approach, effects and problems in gene transformation were discussed in details, and also the strategy and emphases were probed into the future research.

Biodegradation, Environmental↗