2339 Journal of Food Protection, Vol. 71, No. 11, 2008, Pages 2339–2373 Copyright ᮊ, International Association for Food Protection Review Outbreaks Where Food Workers Have Been Implicated in the Spread of Foodborne Disease. Part 4. Infective Doses and Pathogen Carriage EWEN C. D. TODD,1* JUDY D. GREIG,2 CHARLES A. BARTLESON,3 AND BARRY S. MICHAELS4 1Department of Advertising Public Relations and Retailing, Michigan State University, East Lansing, Michigan 48824, USA; 2Public Health Agency of Canada, Laboratory for Foodborne Zoonoses, 160 Research Lane, Unit 206, Guelph, Ontario, Canada N1G 5B2; 3Bartleson Food Safety Consultants, P.O. Box 11983, Olympia, Washington 98508-1983, USA; and 4The B. Michaels Group, Inc., 487 West River Road, Palatka, Florida 32177, USA MS 08-294: Received 17 June 2008/Accepted 18 July 2008 ABSTRACT 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. Pathogens of fecal, nose or throat, and skin origin are most likely to be transmitted by the hands, highlighting the need for effective hand hygiene and other barriers to pathogen contamination, such as no bare hand contact with ready-to-eat food. The pathogens most likely to be transmitted by food workers are norovirus, hepatitis A virus, Salmonella, Shigella, and Staphylococcus aureus. However, other pathogens have been implicated in worker-associated outbreaks or have the potential to be implicated. In this study, the likelihood of pathogen involvement in foodborne outbreaks where infected workers have been implicated was examined, based on infectious dose, carriage rate in the community, duration of illness, and length of pathogen excretion. Infectious dose estimates are based on volunteer studies (mostly early experiments) or data from outbreaks. Although there is considerable uncertainty associated with these data, some pathogens appear to be able to infect at doses as low as 1 to 100 units, including viruses, parasites, and some bacteria. Lengthy postsymptomatic shedding periods and excretion by asymptomatic individuals of many enteric pathogens is an important issue for the hygienic management of food workers. This article is the fourth in a series of several reviewing term carrier. These individuals, their coworkers and man- the role of food workers in foodborne outbreaks. Members agement are typically unaware of their condition, and they of the Committee on Control of Foodborne Illnesses of the are capable of contaminating the kitchen environment over International Association for Food Protection analyzed 816 a period of time unless they practice meticulous hygiene or foodborne disease outbreaks in which food workers were use barriers to prevent pathogen contamination. Interesting- implicated as the source of contamination (80, 194, 195) ly, from the review, an almost equal number of outbreaks and grouped these outbreaks into different types of contam- occurred where workers were asymptomatic (a few were ination scenarios. Specifically, this review deals with the chronic excretors) as those where they were ill. Therefore, doses of pathogens required to infect individuals. These it is important to recognize the risks of infected but appar- pathogens have been or could be involved in foodborne ently well employees. disease outbreaks through worker infection or contamina- tion. It also describes the incubation period, duration, symp- INFECTIVE DOSES FOR FOODBORNE AND tomatic and asymptomatic carriage rates, and persistence of OTHER ENTERIC PATHOGENS pathogen excretion. For the purposes of this report, ‘‘ill’’ is defined as an individual having unambiguous symptoms High numbers of pathogens can be present in fecal that alert the worker that handling food and food contact matter, especially during diarrheal episodes, with levels of 11 surfaces is not appropriate. ‘‘Asymptomatic’’ is defined as up to 10 infectious cells or viral particles per ml or g of 5 9 the condition of individuals who are not obviously ill but feces, although levels of 10 to 10 are more common (7, are colonized and shedding pathogens periodically; this can 33, 65, 203). These situations present opportunities for con- be for a short time before the illness develops (prodrome), tamination by those preparing food and subsequent illnesses subsequent to the illness in the recovery phase, or a long- for those who consume the food. Clearly, the more patho- gens consumed in a food or transferred through other fecal- * Author for correspondence. Tel: 517-355-8371; Fax: 517-432-2589; oral route scenarios, the more likely an illness will result. E-mail: [email protected]. Much work has been conducted to determine minimum in- 2340 TODD ET AL. J. Food Prot., Vol. 71, No. 11 166 106 174, 198 106 14 198 85 129 17, 174 193 185 185 185 185 185 129 106 106 106 116 Published Reference(s) veloping countries veloping countries Probable Unknown, maybe in de- NA Unknown, maybe in de- a Inferred Pathogen implicated in food worker outbreaks b countries, more fre- quent in developing countries veloping countries veloping countries Rare in developed Unknown, maybe in de- NA No No NAUnknown NA Unknown Unknown, maybe in de- food samples 6 Levels in outbreak (CFU/g or CFU/ml) 10 0.3–15 NA NA Ն 3–93 NA NA 0.3–0.4Ͻ NA0.04–0.18 NA 0.1 NA in mettwurst Not known NA Not known (estimat- 3 –10 4 1 (estimated) virus particles) (CFU or no. of 8 (estimated) Infectious dose from ed) 9 2 risk 67.5 organisms/un- cooked patty); medi- an 23 in serveddercooked un- burgers, children most at risk dren 10, 10 100 (estimated) Occasional for O157:H7 Occasional for O157:H7 13.5–675 (median 10 10 Յ Ͻ 2–45, children most at Mean 10 Ͻ Mean 31, school chil- Mean 1,100125–500 43 5–10 NA NA NA NA Ͼ 10 outbreak data and estimates 20 h ; 9 Ͻ with bi- –10 6 10 –10 9 with up to 50% at- with bicarbonate, 9 with bicarbonate, 25– : 46% attack rate, 85% 10 volunteer studies in meal, 30–100% attack 5 , 1–60% attack rate NA NA Infectious dose from 6 9 10 –10 6 –10 –10 –10 (CFU or no. of virus particles) rate; 10 ed; 10 70% attack rate 1978 study of outbreak10 strains: infected 3 7 8 tack rate for diarrhea in carbonate, 13–44% and 100% attack rates 38%, 60% attack rates 800: 10% attack rate, 50% infect- 500 (1 volunteer) Rare Rare 1998 studies: 10 10 1950–1956 studies: 10 10 10 O157:H7 10 (estimated), 10–100 Occasional Occasional Quantitative infectious dose data from volunteer studies and pathogen levels found in foods implicated in outbreaks Pathogen O157:H7 in sala- O157:H7 in veni- O157:H7 in ham- O157:H7 in O157:H7 in mel- O157:H7 in raw O111 e g d c f mi son jerky burger patties pumpkin salad on given to children milk cheese TABLE 1. Campylobacter jejuni EAEC EHEC EPEC Escherichia coli E. coli E. coli E. coli E. coli E. coli E. coli E. coli ETEC EIEC Clostridium perfringens J. Food Prot., Vol. 71, No. 11 INFECTIVE DOSES AND PATHOGEN CARRIAGE 2341 39 174 127 38, 58, 111 139 204 100 100 57 139 86 139 56 56, 58 18, 198 92 78 68 106 Published Reference(s) Occasional a Inferred Pathogen implicated in food worker outbreaks ing Frequent Frequent NA NA NA NA NA NA Occasional but declin- NA NA NA NA NA NA food samples dose: 4.57 log Levels in outbreak (CFU/g or CFU/ml) CFU, 70.9% attack rate eaten 1.07% attack rate 6 0.3 in frankfurters NA NA 0.02–2.50.004–0.46, 65–73 g NA0.0018–0.003623,0000.0036–0.043 NA0.11–0.13 NA NA NA0.06–0.23dose: 1.23 log CFU, NA NA NA NA NA NA NA 0.0310 NA NA (estimat- 3 in 13 out- but could be 11 6 –10 virus particles) (CFU or no. of 1 (estimated) No No Infectious dose from breaks involving 11 types of food for adults 3 ed) as low as 10–100 cells 10 10 10 for children, 25–50 44,000, 34% attack rate11, 1,000 67% attack rate 0.135 NA NA NA NA Ͻ Up to 10 outbreak data and estimates , 3 , 89% 8 , 50% attack 7 , 28% attack rate; 10 5 volunteer studies with six serovars in egg- Infectious dose from 9 , 95% attack rate; 10 –10 (CFU or no. of virus particles) 9 5 0% attack rate attack rate; 10 rate; 10 nog, 17–100% attack rates 10 10 Salmonella Typhi 15–20 to 10 Eastbourne in Enteritidis in Enteritidis in Enteritidis in Heidelberg in Infantis in Javiana and Minnesota in Newport in Newport in Anatum in Cubana in Continued Pathogen chocolate ice cream macaroni salad plain rolled egg Cheddar cheese ham Oranienberg in mozza- rella cheese protein dietary supple- ment ground beef hamburger egg roll filling carmine capsules TABLE 1. Listeria monocytogenes Salmonella Salmonella Salmonella Salmonella Salmonella Salmonella Salmonella Salmonella Salmonella Salmonella Salmonella Nontyphoidal Salmonella Salmonella 2342 TODD ET AL. J. Food Prot., Vol. 71, No. 11 114 3 113 198 54 107 106 106 38, 121 139 4, 58 139 100 198 Published Reference(s) veloping countries Unknown, maybe in de- a Inferred Pathogen implicated in food worker outbreaks countries Frequent but declining Frequent Occasional Occasional NA NA NA NA NA NA 8 food samples Levels in outbreak –10 (CFU/g or CFU/ml) 5 fant, 22–44 salmonel- lae were consumed per day for 36fore h symptoms) be- 55.0% attack rate 2/100 g (in one in- 0.043–0.24 NA NA 10 Ͻ 0.6dose: 3.79 log CFU; 1.52,300 NA NA NA NA NA NA 5 10 Ն 4 years Ͻ g enterotoxin 50 ng enterotoxin NA NA virus particles) (CFU or no.
Details
-
File Typepdf
-
Upload Time-
-
Content LanguagesEnglish
-
Upload UserAnonymous/Not logged-in
-
File Pages35 Page
-
File Size-