As Originally published by Journal of Food Protection,, July 2009
By: Dr. Ewen Todd, et. al.
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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. The most frequent means of worker contamination is the fecal-oral route, and study results have indicated that toilet paper may not stop transmission of pathogens to hands. However, contact with raw foods of animal origin, worker aerosols (from sneezes), vomitus, and exposed hand lesions also have been associated with outbreaks. Transfer of pathogens has been documented through contaminated fabrics and carpets, rings, currency, skin surfaces, dust, and aerosols and though person-to-person transmission. Results of experiments on pathogen survival have indicated that transmission depends on the species, the inoculum delivery route, the contact surface type, the duration and temperature of exposure, and the relative humidity. Generally, viruses and encysted parasites are more resistant than enteric bacteria to adverse environmental conditions, but all pathogens can survive long enough for transfer from a contaminated worker to food, food contact surfaces, or fellow workers.
A lack of understanding in many food service settings concerning the transmission and growth of pathogens (80, 195, 199) can lead to potential foodborne outbreak situations. Similar issues are associated with food prepared in households and served at home or used in home-catering situations, but problems in these settings are much less likely to be reported (80). Such lack of understanding or ignoring the risks of contamination is illustrated by a hepatitis A virus (HAV) outbreak involving an ice-slush beverage contaminated by an infected employee in a convenience market (30). The utensils for the beverage machine used by the infected worker were kept beside the toilet bowl. This gross error in hygiene should have been identified by the management, and appropriate information should have been relayed to employees. Outbreaks also have been caused by workers changing diapers on infants with diarrhea before going to work. Sick children at home are a risk factor for foodborne illness, and effective hand washing practices must be taught and adhered to (113). Even healthy family members may transmit pathogens. For instance, a higher carriage rate for ß-hemolytic streptococci occurs in children, up to 47% in normal school populations (95). In numerous reports from countries where sanitary facilities are lacking, food has become contaminated by unwashed hands and exposure to temperature abuse. Contamination can be transferred to and from workers through raw food, hands (including dirty fingernails, rings, and other jewelry), clothing, aerosols, fomites, food soil, food packages, and other environmental sources and pathogens can survive for extended periods of time on many surfaces, including skin.
Dr. Ewen Todd is a Food Safety Expert with over 45 years of knowledge and experience in general food safety and Food Microbiology Issues. Specifically, he has extensive experience the reporting and surveillance of Foodborne Disease, as well as development of analytical methods for identifying foodborne pathogens. As a result of his work with the industry and his knowledge of foodborne disease, 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.
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1/23/2013· Food & Beverage
By: Dr. Ewen Todd
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.
5/8/2014· Food & Beverage
By: Dr. Ewen Todd
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.
1/27/2014· Food & Beverage
By: Dr. Ewen Todd
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.
