A Disposable Biosensor for Pathogen Detection in Fresh Produce Samples

As the safety in the food supply becomes critical, the demand for rapid, low volume, sensitive and economic biosensor devices have dramatically increased. A novel immunosensor based on electrochemical sandwich immunoassay has been developed for pathogen detection in food. The immunosensor design is based primarily upon the specific nature of labeled antibodyantigen binding. The architecture of the biosensor demonstrates the advantages of using lateral flow format strip attached to a portable circuitry for signal measurement. The ability to change the specificity of the antibodies enables the biosensor to be used as a semi-quantitative detection device for many types of foodborne pathogens. Results show that the biosensor can detect a very low concentration of cells in less than 10 minutes. In addition, the biosensor gives a higher specificity and sensitivity than conventional approaches. Details on the device fabrication and performance of the biosensor in detecting pathogenic organisms in fresh produce are presented. Application of the device can be used to enhance food safety and biosecurity of the food supply chain, as well as it can be used for medical diagnostics and bio-defense measures.

As the safety in the food supply becomes critical, the demand for rapid, low volume, sensitive, and economic biosensing devices has dramatically increased. An immunosensor based on electrochemical sandwich immunoassay using polyaniline has been developed for detecting foodborne pathogens, such as Escherichia coli 0157:H7. The immunosensor design is based primarily upon the specific nature of labeled antibody-antigen binding. The architecture of the biosensor demonstrates the advantages of using lateral flow formal strip attached to a portable circuitry for signal measurement. The ability to change the specificity of the antibodies enables the biosensor to be used as a semi-quantitative detection device for other types of foodborne pathogens. Results show that the biosensor could detect as low as 10/sup 1/ bacterial cells per milliliter in less than 10 minutes. Additionally, the biosensor yields faster results, and is cheaper than conventional approaches. Details on the device fabrication and performance of the biosensor in detecting E. coli 0157:H7 are presented.

A paramount and alluring sphere of research, now-a-days, is food analysis, because of the breakneck augmentation of food enterprise and highly hightened maneuverability of today's populations. The management of food quality is very indispensable both for consumer safeguard as well as the food corporations. The biosensors' application in the field of food analysis is quite propitious for the revealing of food borne pathogens. Biosensor, an analytical device, transforms a biological response into an electrical signal. Bioreceptors and transducers are the two main components of a biosensor. Bioreceptor or biorecognition element is the one which leads to the recognition of target analyte and a transducer, for the conversion of recognized event into a measurable electrical signal. The development of biosensors improved the sensitivity and selectivity of detection techniques for food borne pathogens and is rapid, reliable, effective and highly suitable when used in in situ analysis. Since the security in the food supply becomes crucial because of increased perception among consumers and vying nature of food industries, the necessity for expeditious, low volume and sensitive biosensor devices has productively increased. TM Nevertheless , till date, a very few biosensor systems are available commercially such as Biacore, Spreeta , Reichert SR 7000, Analyte 2000, RAPTOR etc. Since, there is ever growing concern regarding safe food and water supply, it is very obvious that the demand for rapid detecting biosensors will also be increasing at par.

As the safety in the food supply becomes critical, the demand for a rapid, low-volume, and sensitive microbial detection device has dramatically increased. A biosensor based on an electrochemical sandwich immunoassay using polyaniline has been developed for detecting foodborne pathogens, such as Escherichia coli (E. coli) O157:H7. The biosensor is comprised of two types of proteins: capture protein and reporter protein. The capture protein is immobilized on a pad between two electrodes, while the reporter protein is attached to conductive polymers. After adding the sample, the target protein binds to the reporter protein and forms a sandwich complex with the capture protein. The conductive polymer that is attached to the reporter protein serves as a messenger, reporting the amount of target protein captured in the form of an electrical signal. The architecture of the biosensor utilizes a lateral flow format, which allows the liquid sample to move from one pad to another by capillary action. Experiments to evaluate the best construction materials, the optimal polyaniline and antibody concentrations, and the distance between electrodes are highlighted in this paper. Results show that the biosensor could detect approximately 7.8/spl times/10/sup 1/ colony forming unit per milliliter of E. coli O157:H7 in 10 min.

Survey of Retail Alfalfa Sprouts and Mushrooms for the Presence of Escherichia coli O157:H7, Salmonella, and Listeria with BAX, and Evaluation of this Polymerase Chain Reaction–Based System with Experimentally Contaminated Samples

Marion Nestle, author of a recently acclaimed book on food politics, has written a new book devoted to food safety. It is addressed to general readers as well as scientists who wish to know more about the issues underlying disputes about the safety of our food supply but who lack prior knowledge about the food industry, its lobbying and marketing strategies, or the political regulation of food supply and public health. Nestle’s decision to write this book appears to have been partly inspired by the extensive media coverage in recent years given to food scandals, food-borne human diseases, fears with regard to genetically modified foods, and, recently, consideration of the vulnerability of food and water supplies to terrorist activity. This new book presents the thesis that food safety is a political issue. Sections on pathogens in the food supply and food biotechnology are followed by a concluding section that summarizes the main arguments, reviews the reasons why the food supply might serve as a medium of terrorist activity, and makes a number of grounded recommendations regarding the future of food safety. A safe food, according to Nestle, is “one that does not exceed an acceptable level of risk” (p. 16). Decisions about acceptability, it is argued, involve opinions and values, as well as science. For this reason, a “science-based” approach to food safety, which balances risk against benefits and costs and contributes to the estimation of risk, is distinguished from a “value-based” approach focused on the acceptability of risk, which tends to balance risk against dreaded outcomes or feelings of outrage. This point is not presented here in the familiar form of a distinction between expert and lay perceptions of risk. The author recognizes the fact that scientific questions do not arise in value-free contexts and that value-based approaches often consider scientific arguments. The argument is rather that when commercial interests are at stake in decisions about the acceptability of risks, these decisions unavoidably become political issues. Nestle points out that it is often difficult to distinguish science-based from value-based aspects of conflicting policies. Most of the book is accordingly devoted to examining actual disputes about food safety in a manner that distinguishes these aspects. Nestle has sought to write a balanced book rather than a political manifesto. Her perspective is that of a trained scientist and professional nutritionist with considerable experience in consultancy and other dealings with both the food industry and public authorities engaged in the tasks of regulating the safety of food supplies. Nestle is critical of players in both of these fields. She claims and seeks to demonstrate that food companies tend to accord priority to commercial interests rather than consumer protection, even to the point of strongly resisting public policies designed to control pathogens in the food supply, while government agencies often tend to support business interests at the expense of public health. These views are controversial and are unlikely to convince all stakeholders in food safety issues. Nevertheless, they are presented in a series of carefully documented cases, likely to prove useful to readers who approach the text with a view to making up their minds and irritating to those who feel themselves criticized. It is balanced in the sense that one cannot claim that Nestle disregards science-based arguments regarding the safety of food biotechnology, merely that she respects the legitimacy of value-based concerns about genetically modified foods. These include concerns with regard to the environment, health, and the rights of consumers to choose, which in turn impose demands regarding such issues as contamination, traceability, and labeling. Given the interests at stake in these issues, some readers may wish to interpret this stance as support for the anti-biotechnology lobby. This book should be read and discussed in university departments that prepare students for work in food-related fields. It introduces a range of safety concerns that should become salient issues of discussion in the classroom. Its weaker points include a somewhat narrow focus upon national issues. There is a tendency to equate government agencies with existing U.S. institutions, while suggesting in passing that control systems in some European countries are more effective; equally, there is a tendency to equate science with the natural as opposed to the social sciences, neglecting much relevant social research with regard to globalization, distribution networks, and consumption, as well as such issues as trust and accountability. No book, however, can reasonably be expected to cover the entire field. This one raises many important issues and does it well.

Food supply and food safety issues in China

With the global population projected to reach 9 billion by the year 2050, the need for nations to secure food supplies for their populations has never been more pressing. Finding better supply chain solutions is an essential part of achieving a secure and sustainable diet for a rapidly increasing population. We are now in a position, through methods including life cycle assessment (LCA), carbon footprinting and other tools, to accurately measure and assess our use – or misuse – of natural resources, including food. The impact of new technologies and management systems can therefore improve efficiencies and find new ways to reduce waste. Global Food Security and Supply provides robust, succinct information for people who want to understand how the global food system works. The book demonstrates the specific tools available for understanding how food supply works, addresses the challenges facing a secure and safe global food supply, and helps readers to appreciate how these challenges might be overcome. This book is a concise and accessible text that focuses on recent data and findings from a range of international collaborations and studies. The author provides both a snapshot of global food supply and security today, and a projection of where these issues may lead us in the future. This book will therefore be of particular interest to food policy leaders, commercial managers in the food industry, and researchers and students seeking a better understanding of a rapidly evolving topic.

A biosensor for E. coli O157:H7 detection was developed which detected the change inimpedance caused by the presence of cells immobilized on interdigitated gold electrodes. Thesensor was fabricated from a 100 Silicon wafer with a 2m layer of SiO2 as an insulating layer. Thesensor active area contained interdigital gold electrodes deposited over the SiO2 usingphotolithographic processing methods. Analyte specific antibodies were immobilized to the SiO2 inbetween the electrodes creating a biological sensing surface. Using impedance spectroscopy, theimpedance across the interdigital electrodes was measured after immersing the biosensor insolution. Bacteria cells present in solution attached to antibodies and became tethered to the sensorsurface. Immobilized bacteria cells changed the dielectric constant of the media between theelectrodes thereby causing a change in measured impedance. The biosensor was able todiscriminate between different cellular concentrations from 102 - 107 CFU/mL in pure culture with adetection time of 5 minutes. The design, modeling, fabrication and testing of the biosensor isdiscussed along with the implications of these findings towards further biosensor development.

This study assessed the perceptions of Kentucky consumers regarding the safety of the nation's food supply. Data were collected through a telephone survey of 728 respondents. Overall, most consumers were very or somewhat confident in the nation's food supply. Significant differences were noted among consumers based on age, gender and household income. The most likely locations for food safety problems were identified as food processing plants, followed by restaurants. Respondents that were most confident in the nation's food supply believed food poisoning occurred less frequently than those who were not confident in the food supply. Those consumers who were very confident and somewhat confident in the food supply had a significantly different perception of health risks in food from germs, pesticide residues and preservatives than those who had no confidence in the food supply. Respondents with someone in the household working in the foodservice industry were not significantly different in their confidence of the nation's food supply, or in their opinion of where food safety problems occur, than those who did not. Implications for the foodservice and hospitality industry are discussed.

With outbreaks of mad cow, hoof and mouth disease, and the terrorist attacks of September 11, the safety of the American food supply weighs not only on the minds of culinarians, but also on consumers. How is the media framing these issues and how does that affect consumer confidence in the safety of the food supply has come into question. In this experiment, participants were presented with two media frames-food safety and bioterrorism and food security-and were asked questions that measured concern about the safety of the food supply. While the research results did not conclude that media frames of bioterrorism increased concern about the safety of the food supply, it is important to remember that existing media frames of bioterrorism and a general lack of knowledge about pathogens that can threaten food may play an important role in how individuals conceptualize the level of threat to the American food supply.

Detection of five Shiga toxin-producing Escherichia coli genes with multiplex PCR

The near daily news reports on food-borne diseases caused by contaminated produce, dairy, or meats suggests to the public that the safety of the U.S. food supply is in jeopardy. These reports, as well as a general distrust in federal agencies due in part to mad cow disease and toxigenic forms of E. coli in ground beef, have resulted in an increasing demand for foods and an interest in sustainable agriculture (Macilwain, 2004). It is, therefore, timely and appropriate to provide classroom lectures and laboratory experiences to show that microbes are ubiquitous in our environment, including in the foods that we eat (Scholthof, 2001; Scholthof, 2003). In presenting such material, it is important that we distinguish between common microbes and potentially harmful pathogens. In particular, it is imperative to place an emphasis on the fact that many bacteria and fungi are both beneficial and necessary for crop production and robust ecosystems. This hands-on laboratory experience has the added benefit of reinforcing safe food storage and preparation. The lab described in this article was specifically adopted for an undergraduate course Pathogens, the Environment, and Society for the Bioenvironmental Sciences undergraduate degree program at Texas AM Scholthof, 2003). Materials & Methods The goal of this student laboratory experience is to use basic microbiological techniques to examine common bacteria and fungi on fruits and vegetables. Inexpensive conventionally grown produce (see Table 1) that is available year-round was selected from a supermarket. We also purchased organically grown carrots, apples, and tomatoes from the supermarket to determine if there were differences in the types of bacteria and fungi when compared to conventionally produced fruits and vegetables. Alfalfa sprouts were selected because there have been several reports warning about food-borne illnesses that are linked to consuming fresh sprouts (Breuer et al., 2001; Taormina et al., 1999). Preparation Standard microbiology protocols were used for the preparation of growth media. The details for preparing materials and identifying bacteria were based on protocols provided by the Bacteriological Analytical Manual Online (www. cfsan.fda.gov/~ebam/bam-toc.html) and the supplier of the dehydrated culture media (Carolina Biological Supply Co.). Two growth media were used: nutrient broth-yeast extract agar (NBY) and potato dextrose agar (PDA) supplemented with two antibiotics, ampicillin and streptomycin (PDA-AS). NBY was used for bacteria because it allows for good growth of most bacteria with characteristic colony morphology. PDA is a common growth media for isolating fungi. The addition of the antibiotics in PDA-AS is to inhibit bacterial growth, allowing for better development of the fungi. The fungi and bacteria were cultured at 28[degrees] C in a standard laboratory incubator. Alternatively, they can be kept at room temperature, although it will require a longer incubation period. Bacterial growth was apparent after 24 hours. Most fungi were visible on PDA-AS plates within 72 hours. For this laboratory session, two to four students were assigned to a group working with fruits or vegetables. For example, both organic and conventionally farmed produce were tested by Group 1 (apples and peaches), Group 2 (carrots), and Group 3 (tomatoes). …

Fresh sprouts are healthy foods, low in fats and high in phytochemicals, but have a short shelf-life, hence the need for processing methods that preserve their nutritional value. This work was aimed at evaluating the effect of heat-drying (HD) and freeze-drying (FD) on the phytochemical and fatty acid profiles of alfalfa and flax sprouts, as compared to fresh material. Both FD and HD reduced the phytochemical contents compared to fresh sprouts. FD better preserved phytoestrogens, phytosterols and total tocols compared to HD. However, phytoestrogen and tocol content remained quite high also in HD. The fatty acid profile was affected only by sprouts species, with higher amounts of α-linolenic acid in flax and linoleic acid in alfalfa sprouts. This work demonstrates that drying does not severely compromise the nutritional value of sprouts and provides a valid support for the choice of the drying method depending on the compound to be preserved, and taking into consideration the different cost of the methods. In addition, sprout powder is easy to handle and, due to its low volume, does not imply a decrease of feed consumption and energy intake, which is relevant in its use as a supplement in human and animal feeding. © 2019 Society of Chemical Industry.

The incidence of foodborne diseases has continuingly increased over the years and resulted in public health problem globally. EnterohemorrhagicEscherichia coliO157:H7 (E. coliO157:H7) is a human pathogen that causes diarrhea and hemorrhagic colitis.E. coliO157:H7 can be found in various foods. It is important to detect this foodborne pathogen to provide safe food supply. A lot of methods, for example, culture and PCR‐based test, used to detect foodborne pathogens are laborious and time consuming. Hence, a variety of methods have been developed for rapid, simple and reliable detection ofE. coliO157:H7 as it is required in many food analyses. Lateral flow immunoassay (LFIA) are advantageous over conventional detection methods in terms of their rapidity and simplicity for end user, especially the LFIA can be developed as the strip test for on‐site point‐of‐care test (POCT) products. Gold nanoparticles (AuNPs; colloid gold) are the most commonly used labels in the LFIA for the visual analysis, however, there are still several limitations that restrict their applications of traditional LFIA. Therefore, recent reports on improved LFIA forE. coliO157:H7 detection in foods are continuously reported. This review intends to provide these recent advances in improved LFIA methods for the detection ofE. coliO157:H7 in foods.