Assessment and control of Bacillus cereus emetic toxin in food

Despite of improving levels of hygiene, the incidence of registered food borne disease has been at the same level for many years: there were 40 to 90 epidemics in which 1000-9000 persons contracted food poisoning through food or drinking water in Finland. Until the year 2004 salmonella and campylobacter were the most common bacterial causes of food borne diseases, but in years 2005-2006 Bacillus cereus was the most common. Similar developement has been published i.e. in Germany already in the 1990´s. One reason for this can be Bacillus cereus and its emetic toxin, cereulide. Bacillus cereus is a common environmental bacterium that contaminates raw materials of food. Otherwise than salmonella and campylobacter, Bacillus cereus is a heat resistant bacterium, capable of surviving most cooking procedures due to the production of highly thermo resistant spores. The food involved has usually been heat treated and surviving spores are the source of the food poisoning. The heat treatment induces germination of the spore and the vegetative cells then produce toxins. This doctoral thesis research focuses on developing methods for assessing and eliminating risks to food safety by cereulide producing Bacillus cereus. The biochemistry and physiology of cereulide production was investigated and the results were targeted to offer tools for minimizing toxin risk in food during the production. I developed methods for the extraction and quantitative analysis of cereulide directly from food. A prerequisite for that is knowledge of the chemical and physical properties of the toxin. Because cereulide is practically insoluble in water, I used organic solvents; methanol, ethanol and pentane for the extraction. For extraction of bakery products I used high temperature (100C) and pressure (103.4 bars). Alternaties for effective extraction is to flood the plain food with ethanol, followed by stationary equilibration at room temperature. I used this protocol for extracting cereulide from potato puree and penne. Using this extraction method it is also possible also extract cereulide from liquid food, like milk. These extraction methods are important improvement steps for studying of Bacillus cereus emetic food poisonings. Prior my work, cereulide extraction was done using water. As the result, the yield was poor and variable. To investigate suspected food poisonings, it is important to show actual toxicity of the incriminated food. Many toxins, but not cereulide, inactivate during food processing like heating. The next step is to identify toxin by chemical methods. I developed with my colleague Maria Andesson a rapid assay for the detection of cereulide toxicity, within 5 to 15 minutes. By applying this test it is possible to rapidly detect which food was causing the food poisoning. The chemical identification of cereulide was achieved using mass spectrometry. I used cereulide specific molecular ions, m/z (+/-0.3) 1153.8 (M+H+), 1171.0 (M+NH4+), 1176.0 (M+Na+) and 1191.7 (M+K+) for reliable identification. I investigated foods to find out their amenability to accumulate cereulide. Cereulide was formed high amounts (0.3 to 5.5 microg/g wet wt) when of cereulide producing B. cereus strains were present in beans, rice, rice-pastry and meat-pastry, if stored at non refrigerated temperatures (21-23C). Rice and meat pastries are frequently consumed under conditions where no cooled storage is available e.g. picnics and outdoor events. Bacillus cereus is a ubiquitous spore former and is therefore difficult to eliminate from foods. It is therefore important to know which conditions will affect the formation of cereulide in foods. My research showed that the cereulide content was strongly (10 to 1000 fold differences in toxin content) affected by the growth environment of the bacterium. Storage of foods under nitrogen atmosphere (> 99.5 %) prevented the production of cereulide. But when also carbon dioxide was present, minimizing the oxygen contant (< 1%) did not protect the food from formation of cereulide in preliminary experiments. Also food supplements affected cereulide production at least in the laboratory. Adding free amino acids, leucine and valine, stimulated cereulide production 10 to 20 fold. In peptide bonded form these amino acids are natural constituents in all proteins. Interestingly, adding peptide bonded leucine and valine had no significant effect on cereulide production. Free amino acids leucine and valine are approved food supplements and widely used as flawour modifiers in food technology. My research showed that these food supplements may increase food poisoning risk even though they are not toxic themselves.

Information, risk and trust in the food chain : Ex-ante valuation of consumer willingness to pay for beef quality information using the contingent valuation method

The safety of food has become an increasingly interesting issue to consumers and the media. It has also become a source of concern, as the amount of information on the risks related to food safety continues to expand. Today, risk and safety are permanent elements within the concept of food quality. Safety, in particular, is the attribute that consumers find very difficult to assess. The literature in this study consists of three main themes: traceability; consumer behaviour related to both quality and safety issues and perception of risk; and valuation methods. The empirical scope of the study was restricted to beef, because the beef labelling system enables reliable tracing of the origin of beef, as well as attributes related to safety, environmental friendliness and animal welfare. The purpose of this study was to examine what kind of information flows are required to ensure quality and safety in the food chain for beef, and who should produce that information. Studying the willingness to pay of consumers makes it possible to determine whether the consumers consider the quantity of information available on the safety and quality of beef sufficient. One of the main findings of this study was that the majority of Finnish consumers (73%) regard increased quality information as beneficial. These benefits were assessed using the contingent valuation method. The results showed that those who were willing to pay for increased information on the quality and safety of beef would accept an average price increase of 24% per kilogram. The results showed that certain risk factors impact consumer willingness to pay. If the respondents considered genetic modification of food or foodborne zoonotic diseases as harmful or extremely harmful risk factors in food, they were more likely to be willing to pay for quality information. The results produced by the models thus confirmed the premise that certain food-related risks affect willingness to pay for beef quality information. The results also showed that safety-related quality cues are significant to the consumers. In the first place, the consumers would like to receive information on the control of zoonotic diseases that are contagious to humans. Similarly, other process-control related information ranked high among the top responses. Information on any potential genetic modification was also considered important, even though genetic modification was not regarded as a high risk factor.

Promoting kangaroo as a sustainable option for meat production on the rangelands of Australia

Implications •As kangaroo meat is sourced from native wildlife, conservation of the species is important in developing sustainable meat harvesting. Landholders, conservationists, and commercial meat producers need to work together to achieve this goal. •The production of high quality meat products from field-harvested carcasses can be augmented through a better understanding of the impact that field conditions and carcass handling have on final meat eating quality. •Food safety is also paramount, with measures taken to minimize the impacts of parasitism and microbial contamination. Any breaches of inspection protocols can only serve to undermine consumer confidence and viability of the industry.

Fate of key food-borne pathogens associated with intensive pig and poultry farming environments

Intensive pig and poultry farming in Australia can be a source of pathogens with implications for food-safety and/or human illness. Seven studies were undertaken with the following objectives: · Assess the types of zoonotic pathogens in waste · Assess the transfer of pathogens during re-use both within the shed and externally in the environment · The potential for movement of pathogens via aerosols In the first and second studies the extent of zoonotic pathogens was evaluated in both piggery effluent and chicken litter and Salmonella and Campylobacter were detected in both wastes. In the third study the dynamics of Salmonella during litter re-use was examined and results showed a trend for lower Salmonella levels and serovar diversity in re-used litter compared to new litter. Thus, re-use within the poultry farming system posed no increased risk. The fourth study addressed the direct risks of pathogens to farm workers due to reuse of piggery effluent within the pig shed. Based on air-borne Escherichia coli (E. coli) levels, re-using effluent did not pose a risk. In the fifth study high levels of Arcobacter spp. were detected in effluent ponds and freshly irrigated soils with potential food-safety risks during the irrigation of food-crops and pasture. The sixth and seventh studies addressed the risks from aerosols from mechanically ventilated sheds. Staphylococci were shown to have potential as markers, with airborne levels gradually dropping and reaching background levels at 400 m distance. Salmonella was detected (at low levels) both inside and outside the shed (at 10 m). Campylobacter was detected only once inside the shed during the 3-year period (at low levels). Results showed there was minimal risk to humans living adjacent to poultry farms This is the first comprehensive analysis studying key food-safety pathogens and potential public health risks associated with intensively farmed pigs and poultry in Australia.

Overview on different sterilization techniques for baby food

The nutritional quality of the product as well as other quality attributes like microbiological and sensory quality are essential factors in baby food industry, and therefore different alternative sterilizing methods for conventional heating processes are of great interest in this food sector. This report gives an overview on different sterilization techniques for baby food. The report is a part of the work done in work package 3 ”QACCP Analysis Processing: Quality – driven distribution and processing chain analysis“ in the Core Organic ERANET project called Quality analysis of critical control points within the whole food chain and their impact on food quality, safety and health (QACCP). The overall objective of the project is to optimise organic production and processing in order to improve food safety as well as nutritional quality and increase health promoting aspects in consumer products. The approach will be a chain analysis approach which addresses the link between farm and fork and backwards from fork to farm. The objective is to improve product related quality management in farming (towards testing food authenticity) and processing (towards food authenticity and sustainable processes. The articles in this volume do not necessarily reflect the Core Organic ERANET’s views and in no way anticipate the Core Organic ERANET’s future policy in this area. The contents of the articles in this volume are the sole responsibility of the authors. The information contained here in, including any expression of opinion and any projection or forecast, has been obtained from sources believed by the authors to be reliable but is not guaranteed as to accuracy or completeness. The information is supplied without obligation and on the understanding that any person who acts upon it or otherwise changes his/her position in reliance thereon does so entirely at his/her own risk. The writers gratefully acknowledge the financial support from the Core Organic Funding Body: Ministry of Agriculture and Forestry, Finland, Swiss Federal Office for Agriculture, Switzerland and Federal Ministry of Consumer Protection, Food and Agriculture, Germany.

黄土高原半干旱区农田干旱防御与抗旱措施

系统分析农田抗旱管理与相应措施对黄土高原半干旱区社会和经济的协调健康发展以及粮食安全具有重要意义。黄土高原半干旱区干旱发生的特点决定了农田抗旱管理的复杂性和艰巨性。论文阐述了农田抗旱管理中防、抗与避三种措施的主要内容,并就农田抗旱管理系统进行了介绍。认为通过建立完善的农业技术推广服务体系和针对地区特点的抗旱管理措施,是半干旱区农业可持续发展一项重要而积极的对策,不仅需要从资金和政策上给予扶持和倾斜,更需要在管理机制上予以重视。

Development and assessment of new sensor systems in food packaging applications

The use of optical sensor technology for non-invasive determination of key quality pack parameters improved package/product quality. This technology can be used for optimization of packaging processes, improvement of product shelf-life and maintenance of quality. In recent years, there has been a major focus on O2 and CO2 sensor development as these are key gases used in modified atmosphere packaging (MAP) of food. The first and second experimental chapters (chapter 2 and 3) describe the development of O2, pH and CO2 solid state sensors and its (potential) use for food packaging applications. A dual-analyte sensor for dissolved O2 and pH with one bi-functional reporter dye (meso-substituted Pd- or Ptporphyrin) embedded in plasticized PVC membrane was developed in chapter 2. The developed CO2 sensor in chapter 3 was comprised of a phosphorescent reporter dye Pt(II)- tetrakis(pentafluorophenyl) porphyrin (PtTFPP) and a colourimetric pH indicator α-naphtholphthalein (NP) incorporated in a plastic matrix together with a phase transfer agent tetraoctyl- or cetyltrimethylammonium hydroxide (TOA-OH or CTA-OH). The third experimental chapter, chapter 4, described the development of liquid O2 sensors for rapid microbiological determination which are important for improvement and assurance of food safety systems. This automated screening assay produced characteristic profiles with a sharp increase in fluorescence above the baseline level at a certain threshold time (TT) which can be correlated with their initial microbial load and was applied to various raw fish and horticultural samples. Chapter 5, the fourth experimental chapter, reported upon the successful application of developed O2 and CO2 sensors for quality assessment of MAP mushrooms during storage for 7 days at 4°C.

The human impacts of flower farm development in the Ethiopian Rift Valley region

The flower industry has a reputation for heavy usage of toxic chemicals and polluting the environment, enormous consumption of water, and poor working condition and low wage level in various parts of the world. It is unfortunate that this industry is adamant to change and repeating the same mistakes in Ethiopia. Because of this, - there is a growing concern among the general public and the international community about sustainability of the Ethiopian flower industry. Consequently, working conditions in the flower industry, impacts of wage income on the livelihoods of employees, coping strategies of low wage flower farm workers, impacts of flower farms on the livelihoods of local people and environmental pollution and conflict, were analysed. Both qualitative and quantitative research methods were employed. Four quantitative data sets: labour practice, employees’ income and expenditure, displaced household, and flower grower views survey were collected between 2010 and 2012. Robust regression to identify the determinants of wage levels, and Multinomial logit to identify the determinants of coping strategies of flower farm workers and displaced households were employed. The findings show the working conditions in flower farms are characterized by low wages, job insecurity and frequent violation of employees’ rights, and poor safety measures. To ensure survival of their family, land dispossessed households adopt a wide range of strategies including reduction in food consumption, sharing oxen, renting land, share cropping, and shifting staple food crops. Most experienced scarcity of water resources, lack of grazing areas, death of herds and reduced numbers of livestock due to water source pollution. Despite the Ethiopian government investment in attracting and creating conducive environment for investors, not much was accomplished when it comes to enforcing labour laws and environmental policies. Flower farm expansion in Ethiopia, as it is now, can be viewed as part of the global land and water grab and is not all inclusive and sustainable. Several recommendations are made to improve working conditions, maximize the benefits of flower industry to the society, and to the country at large.

Assessment of dietary background exposure of the Irish adult population to dioxins and PCBs particularly taking into account additional exposure due to the 2008 Irish dioxin food contamination incident

Irish monitoring data on PCDD/Fs, DL-PCBs and Marker PCBs were collated and combined with Irish Adult Food Consumption Data, to estimate dietary background exposure of Irish adults to dioxins and PCBs. Furthermore, all available information on the 2008 Irish pork dioxin food contamination incident was collated and analysed with a view to evaluate any potential impact the incident may have had on general dioxin and PCB background exposure levels estimated for the adult population in Ireland. The average upperbound daily intake of Irish adults to dioxins Total WHO TEQ (2005) (PCDD/Fs & DLPCBs) from environmental background contamination, was estimated at 0.3 pg/kg bw/d and at the 95th percentile at 1 pg/kg bw/d. The average upperbound daily intake of Irish adults to the sum of 6 Marker PCBs from environmental background contamination ubiquitous in the environment was estimated at 1.6 ng/kg bw/d and at the 95th percentile at 6.8 ng/kg bw/d. Dietary background exposure estimates for both dioxins and PCBs indicate that the Irish adult population has exposures below the European average, a finding which is also supported by the levels detected in breast milk of Irish mothers. Exposure levels are below health based guidance values and/or Body Burdens associated with the TWI (for dioxins) or associated with a NOAEL (for PCBs). Given the current toxicological knowledge, based on biomarker data and estimated dietary exposure, general background exposure of the Irish adult population to dioxins and PCBs is of no human health concern. In 2008, a porcine fat sample taken as part of the national residues monitoring programme led to the detection of a major feed contamination incidence in the Republic of Ireland. The source of the contamination was traced back to the use of contaminated oil in a direct-drying feed operation system. Congener profiles in animal fat and feed samples showed a high level of consistency and pinpointed the likely source of fuel contamination to be a highly chlorinated commercial PCB mixture. To estimate additional exposure to dioxins and PCBs due to the contamination of pig and cattle herds, collection and a systematic review of all data associated with the contamination incident was conducted. A model was devised that took into account the proportion of contaminated product reaching the final consumer during the 90 day contamination incident window. For a 90 day period, the total additional exposure to Total TEQ (PCDD/F &DL-PCB) WHO (2005) amounted to 407 pg/kg bw/90d at the 95th percentile and 1911 pg/kg bw/90d at the 99th percentile. Exposure estimates derived for both dioxins and PCBs showed that the Body Burden of the general population remained largely unaffected by the contamination incident and approximately 10 % of the adult population in Ireland was exposed to elevated levels of dioxins and PCBs. Whilst people in this 10 % cohort experienced quite a significant additional load to the existing body burden, the estimated exposure values do not indicate approximation of body burdens associated with adverse health effects, based on current knowledge. The exposure period was also limited in time to approximately 3 months, following the FSAI recall of contaminated meat immediately on detection of the contamination. A follow up breast milk study on Irish first time mothers conducted in 2009/2010 did not show any increase in concentrations compared to the study conducted in 2002. The latter supports the conclusion that the majority of the Irish adult population was not affected by the contamination incident.

Priority research questions for the UK food system

The rise of food security up international political, societal and academic agendas has led to increasing interest in novel means of improving primary food production and reducing waste. There are however, also many 'post-farm gate' activities that are critical to food security, including processing, packaging, distributing, retailing, cooking and consuming. These activities all affect a range of important food security elements, notably availability, affordability and other aspects of access, nutrition and safety. Addressing the challenge of universal food security, in the context of a number of other policy goals (e.g. social, economic and environmental sustainability), is of keen interest to a range of UK stakeholders but requires an up-to-date evidence base and continuous innovation. An exercise was therefore conducted, under the auspices of the UK Global Food Security Programme, to identify priority research questions with a focus on the UK food system (though the outcomes may be broadly applicable to other developed nations). Emphasis was placed on incorporating a wide range of perspectives ('world views') from different stakeholder groups: policy, private sector, non-governmental organisations, advocacy groups and academia. A total of 456 individuals submitted 820 questions from which 100 were selected by a process of online voting and a three-stage workshop voting exercise. These 100 final questions were sorted into 10 themes and the 'top' question for each theme identified by a further voting exercise. This step also allowed four different stakeholder groups to select the top 7-8 questions from their perspectives. Results of these voting exercises are presented. It is clear from the wide range of questions prioritised in this exercise that the different stakeholder groups identified specific research needs on a range of post-farm gate activities and food security outcomes. Evidence needs related to food affordability, nutrition and food safety (all key elements of food security) featured highly in the exercise. While there were some questions relating to climate impacts on production, other important topics for food security (e.g. trade, transport, preference and cultural needs) were not viewed as strongly by the participants.

Food-poisoning and commercial air travel

With the introduction of budget airlines and greater competitiveness amongst all airlines, air travel has now become an extremely popular form of travel, presenting its own unique set of risks from food poisoning. Foodborne illness associated with air travel is quite uncommon in the modern era. However, when it occurs, it may have serious implications for passengers and when crew are affected, has the potential to threaten safety. Quality, safe, in-flight catering relies on high standards of food preparation and storage; this applies at the airport kitchens (or at subcontractors' facilities), on the aircraft and in the transportation vehicles which carry the food from the ground source to the aircraft. This is especially challenging in certain countries. Several foodborne outbreaks have been recorded by the airline industry as a result of a number of different failures of these systems. These have provided an opportunity to learn from past mistakes and current practice has, therefore, reached such a standard so as to minimise risk of failures of this kind. This review examines: (i) the origin of food safety in modern commercial aviation; (ii) outbreaks which have occurred previously relating to aviation travel; (iii) the microbiological quality of food and water on board commercial aircraft; and (iv) how Hazard Analysis Critical Control Points may be employed to maintain food safety in aviation travel.

Trends in product recalls within the agri-food industry:Empirical evidence from the USA, UK and the Republic of Ireland

The increasing frequency of product recalls within the agri-food industry has led many to question food safety. Research studies also often focus on biological hazards without considering how past, present and emerging risks change over time. We undertake a systematic review of the different biological, operational and chemical hazards within the agri-food industry using a dataset of 2070 registered food recalls in the USA, UK and Republic of Ireland between 2004 and 2010. We show product recalls have become more frequent over time and operational hazards, rather than biological and chemical hazards, are the most frequent recall type within the agri-food industry. © 2012 Elsevier Ltd. All rights reserved.

Effect-based proteomic detection of growth promoter abuse

Unregulated growth promoter use in food-producing animals is an issue of concern both from food safety and animal welfare perspectives. However, the monitoring of such practices is analytically challenging due to the concerted actions of users to evade detection. Techniques based on the monitoring of biological responses to exogenous administrations have been proposed as more sensitive methods to identify treated animals. This study has, for the first time, profiled plasma proteome responses in bovine animals to treatment with nortestosterone decanoate and 17 beta-oestradiol benzoate, followed by dexamethasone administration. Two-dimensional fluorescence differential in-gel electrophoresis analysis revealed a series of hepatic and acute-phase proteins within plasma whose levels were up- or down-regulated within phases of the treatment regime. Surface plasmon resonance (SPR) immuno-assays were developed to quantify responses of identified protein markers during the experimental treatment study with a view to developing methods which can be used as screening tools for growth promoter abuse detection. SPR analysis demonstrated the potential for plasma proteins to be used as indicative measures of growth promoter administrations and concludes that the sensitivity and robustness of any detection approach based on plasma proteome analysis would benefit from examination of a range of proteins representative of diverse biological processes rather being reliant on specific individual markers.

Biosensors for the analysis of microbiological and chemical contaminants in food

Increases in food production and the ever-present threat of food contamination from microbiological and chemical sources have led the food industry and regulators to pursue rapid, inexpensive methods of analysis to safeguard the health and safety of the consumer. Although sophisticated techniques such as chromatography and spectrometry provide more accurate and conclusive results, screening tests allow a much higher throughput of samples at a lower cost and with less operator training, so larger numbers of samples can be analysed. Biosensors combine a biological recognition element (enzyme, antibody, receptor) with a transducer to produce a measurable signal proportional to the extent of interaction between the recognition element and the analyte. The different uses of the biosensing instrumentation available today are extremely varied, with food analysis as an emerging and growing application. The advantages offered by biosensors over other screening methods such as radioimmunoassay, enzyme-linked immunosorbent assay, fluorescence immunoassay and luminescence immunoassay, with respect to food analysis, include automation, improved reproducibility, speed of analysis and real-time analysis. This article will provide a brief footing in history before reviewing the latest developments in biosensor applications for analysis of food contaminants (January 2007 to December 2010), focusing on the detection of pathogens, toxins, pesticides and veterinary drug residues by biosensors, with emphasis on articles showing data in food matrices. The main areas of development common to these groups of contaminants include multiplexing, the ability to simultaneously analyse a sample for more than one contaminant and portability. Biosensors currently have an important role in food safety; further advances in the technology, reagents and sample handling will surely reinforce this position.