Dr. Ewen Todd
is a Food Safety Expert
with over 45 years of experience in the reporting and surveillance of Foodborne Disease
, as well as development of analytical methods for identifying foodborne pathogens. As a result of his knowledge of foodborne disease and work researching different pathogens and toxins, Dr. Todd has influenced research programs and regulatory approaches taken by the Health Protection Branch of Health Canada. In the US, he held the position of Director of the National Food Safety and Toxicology Center and the Food Safety Policy Center at Michigan State University. A leader in microbial research, foodborne disease surveillance, costing of outbreaks, food safety policy, seafood toxins, standard setting, risk assessment, risk management and risk communication, his presentations and food safety programs have been influential in many countries including China, Cambodia, Japan, United Arab Emirates, Lebanon, Kuwait, Saudi Arabia, Europe, as well as Canada, and the USA.
Dr. Todd has delivered over 400 presentations and posters at national and international meetings, with over 200 invitations to speak and teach workshops. An acclaimed author in the field of Foodborne Illness
, he has written 109 research papers, 16 reviews, 36 book chapters and booklets, 40 departmental publications, 37 conference proceedings, 9 laboratory methods, 56 investigational and editorial articles, 90 published abstracts, and 3 editing of proceedings or books. Dr. Todd has received 20 appointments and awards, including the Excellence in Science Award for 1998, the first to be awarded by Health Canada. He is a Fellow of the American Association for the Advancement of Science, the International Association for Food Protection and MSU University Outreach and Engagement as well as Editor in Chief for the Elsevier Encyclopaedia of Food Safety.
Dr. Todd's Consulting services are available to businesses and governments internationally. He responds to telephone calls, emails, and written requests for information on food and waterborne disease.
Consulting Services Include
View Expert Witness Profile
- General Food Safety and Spoilage Issues
- HACCP and GHP Systems
- Standards for Poultry
- Listeria Monocytogenes in Soft Cheeses
- Standards for Poultry
- Seafood Toxins
- Food Workers
- Investigation of Foodborne and Waterborne Illnesses
- Foodborne Disease Surveillance Systems
- Risk Assessment, Risk Management and Risk Governance
- Safety of Aquaculture Systems
- Norovirus in Elder Care and Other Facilities
- Salmonella and Shigella in Schools and Child Care Centers
- Salmonella in Tahini and Other Oil-based Foods
- Escherichia coli O157:H7 in Leafy Greens
- Staphylococcus aureus in Cheese, Clostridium botulinum in Canned or Preserved Food and Native American / Inuit Fermented Food
- Listeria monocytogenes in Deli Meats and Soft Cheeses
- Controlling Listeria monocytogenes in Ready-to-eat Foods
- Hydrophobic Grid Membrane Filter Systems
Hand washing with soap is a practice that has long been recognized as a major barrier to the spread of disease in food production, preparation, and service and in health care settings, including hospitals, child care centers, and elder care facilities. Many of these settings present multiple opportunities for spread of pathogens within at-risk populations, and extra vigilance must be applied. Unfortunately, hand hygiene is not always carried out effectively, and both enteric and respiratory diseases are easily spread in these environments. Where water is limited or frequent hand hygiene is required on a daily basis, such as for many patients in hospitals and astronauts in space travel, instant sanitizers or sanitary wipes are thought to be an effective way of preventing contamination and spread of organisms among coworkers and others. Most concerns regarding compliance are associated with the health care field, but the food industry also must be considered.
Alcohol compounds are increasingly used as a substitute for hand washing in health care environments and some public places because these compounds are easy to use and do not require water or hand drying materials. However, the effectiveness of these compounds depends on how much soil (bioburden) is present on the hands. Workers in health care environments and other public places must wash their hands before using antiseptics and/or wearing gloves. However, alcohol-based antiseptics, also called rubs and sanitizers, can be very effective for rapidly destroying some pathogens by the action of the aqueous alcohol solution without the need for water or drying with towels.
During various daily activities at home and work, hands quickly become contaminated. Some activities increase the risk of finger contamination by pathogens more than others, such as the use of toilet paper to clean up following a diarrheal episode, changing the diaper of a sick infant, blowing a nose, or touching raw food materials. Many foodborne outbreak investigation reports have identified the hands of food workers as the source of pathogens in the implicated food. The most convenient and efficient way of removing pathogens from hands is through hand washing. Important components of hand washing are potable water for rinsing and soaps to loosen microbes from the skin. Hand washing should occur after any activity that soils hands and certainly before preparing, serving, or eating food.
The role played by food workers and other individuals in the contamination of food has been identified as an important contributing factor leading to foodborne outbreaks. To prevent direct bare hand contact with food and food surfaces, many jurisdictions have made glove use compulsory for food production and preparation. When properly used, gloves can substantially reduce opportunities for food contamination. However, gloves have limitations and may become a source of contamination if they are punctured or improperly used. Experiments conducted in clinical and dental settings have revealed pinhole leaks in gloves.
Contamination of food and individuals by food workers has been identified as an important contributing factor during foodborne illness investigations. Physical and chemical barriers to prevent microbial contamination of food are hurdles that block or reduce the transfer of pathogens to the food surface from the hands of a food worker, from other foods, or from the environment. In food service operations, direct contact of food by hands should be prevented by the use of barriers, especially when gloves are not worn. Although these barriers have been used for decades in food processing and food service operations, their effectiveness is sometimes questioned or their use may be ignored. Physical barriers include properly engineered building walls and doors to minimize the flow of outside particles and pests to food storage and food preparation areas; food shields to prevent aerosol contamination of displayed food by customers and workers; work clothing designated strictly for work (clothing worn outdoors can carry undesirable microorganisms, including pathogens from infected family members, into the work environment); and utensils such as spoons, tongs, and deli papers to prevent direct contact between hands and the food being prepared or served. Money and ready-to-eat foods should be handled as two separate operations, preferably by two workers.
This article, the sixth in a series reviewing the role of food workers in foodborne outbreaks, describes the source and means of pathogen transfer. The transmission and survival of enteric pathogens in the food processing and preparation environment through human and raw food sources is reviewed, with the main objective of providing information critical to the reduction of illness due to foodborne outbreaks. Pathogens in the food preparation area can originate from infected food workers, raw foods, or other environmental sources. These pathogens can then spread within food preparation or processing facilities through sometimes complex pathways and may infect one or more workers or the consumer of foods processed or prepared by these infected workers.
In this article, the fifth in a series reviewing the role of food workers in foodborne outbreaks, background information on the routes of infection for food workers is considered. Contamination most frequently occurs via the fecal-oral route, when pathogens are present in the feces of ill, convalescent, or otherwise colonized persons. It is difficult for managers of food operations to identify food workers who may be excreting pathogens, even when these workers report their illnesses, because workers can shed pathogens during the prodrome phase of illness or can be long-term excretors or asymptomatic carriers.
In this article, the fourth in a series reviewing the role of food workers in foodborne outbreaks, background information on the presence of enteric pathogens in the community, the numbers of organisms required to initiate an infection, and the length of carriage are presented. Although workers have been implicated in outbreaks, they were not always aware of their infections, either because they were in the prodromic phase before symptoms began or because they were asymptomatic carriers.
In this article, the third in a series of several reviewing the role of food workers in 816 foodborne outbreaks, factors contributing to outbreaks and descriptions of different categories of worker involvement are discussed.
This article is the second in a series of several by members of the Committee on the Control of Foodborne Illness of the International Association of Food Protection, and it continues the analysis of 816 outbreaks where food workers were implicated in the spread of foodborne disease.
Food workers in many settings have been responsible for foodborne disease outbreaks for decades, and there is no indication that this is diminishing. The Committee on Control of Foodborne Illnesses of the International Association for Food Protection was tasked with collecting and evaluating any data on worker-associated outbreaks.