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Canadian Paediatric Society

Practice Point

Foodborne infections

Posted: Nov 1 2008 | Reaffirmed: Feb 1 2016


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Principal author(s)

DL Moore; Canadian Paediatric Society, Infectious Diseases and Immunization Committee

Paediatr Child Health 2008;13(9):779-82

The purpose of the present Paediatric Infectious Diseases Note is to provide practical guidance to physicians who counsel patients on food safety [1]. Food safety has become an important public health issue in North America. A sentinel system for active foodborne disease surveillance has been in place in the United States since 1996 [2], and a similar system has recently been established in Canada [3]. In the United States, there has been a significant decline in the incidence of several foodborne infections in recent years, possibly attributable to implementation of safety initiatives [4]-[6].

Background

The number of reported cases of enteric infections, most of which are foodborne, increased in many countries in the 1990s [7]-[10]. New pathogens (Cryptosporidium, Cyclospora, calicivirus and norovirus) have emerged or have been recognized as foodborne [5][8][10]. In addition, the population of immunocompromised patients who are highly susceptible to enteric pathogens has increased [11][12].

Foodborne pathogens have also been recognized as causes of severe extraintestinal disease [13]. Infection with Escherichia coli O157 is an important cause of hemolytic-uremic syndrome [14][15]. In the United Kingdom, variant Creutzfeldt-Jakob disease is linked to contaminated beef [16][17]. Reactive arthritis after enteric bacterial pathogens, Guillain-Barré syndrome after Campylobacter enteritis, and disseminated Listeria in newborns of infected pregnant women are other examples [13][18].

Historically, vehicles for the transmission of foodborne infections have included undercooked meat, poultry or seafood, and unpasteurized milk. Uncracked eggs used to be considered safe. It is now recognized that Salmonella endemic in egg-laying flocks can contaminate intact eggs and, thus, inadequately cooked eggs have become a significant cause of infection. Fresh fruits and vegetables are increasingly reported as causes of foodborne outbreaks. Contaminated alfalfa sprouts, imported raspberries, tomatoes, cantaloupes, scallions and leaf lettuce, as well as unpasteurized apple juice, cider, orange juice and carrot juice have all been implicated [5][8][10][19][20]. Table 1 summarizes the main food items that have been associated with foodborne illnesses and the principal microorganisms involved. Alerts on new outbreaks of foodborne disease are posted on the Health Canada Web site [21].

TABLE 1
Potentially contaminated food products

Food

Major organisms involved

Recommendation

Unpasteurized milk, cheese and other dairy products

Salmonella, Campylobacter, Escherichia coli O157, Listeria, Mycobacterium bovis, Brucella

Children should not drink unpasteurized milk or eat unpasteurized soft cheeses

Unpasteurized fruit or vegetable juices

E coli O157, Salmonella, Clostridium botulinum

Children should drink only pasteurized juice products, unless the fruit or vegetable is washed and the juice is freshly squeezed immediately before consumption

Eggs

Salmonella

Children should not eat raw or undercooked eggs, unpasteurized powdered eggs or products containing raw eggs

Raw or undercooked meat, poultry

Salmonella, Campylobacter, E coli O157, Yersinia, Listeria, Toxoplasma, Brucella, Trichinosis

Children should not eat raw or undercooked meat, poultry or meat products (including hot dogs)

Raw fish and shell fish

Vibrios, norovirus, hepatitis A, many other pathogens, toxins and parasites

Children not eat raw shellfish. Some experts caution against eating any raw fish

Fresh fruits and vegetables

Cryptosporidium, Cyclospora, calicivirus, norovirus, Giardia, Shigella, E coli O157, other E coli species, hepatitis A

All fruits and vegetables should be washed before they are eaten. Lettuce, spinach and other salad greens require careful attention.

Sprouts
(alfalfa, mung bean)

Salmonella, E coli O157, hepatitis A

Children should avoid eating raw or undercooked alfalfa, mung bean or other sprouts. Seeds sold for sprouting may be contaminated

Honey

C botulinum

Children younger than one year of age should not be given honey

Cream-filled pastry; potato, egg or other salad with creamy dressing

Staphylococcus aureus, Bacillus cereus

These items should be eaten immediately on preparation or stored promptly in the refrigerator

The consumer and food safety in a changing food environment

Food safety is the responsibility of the food industry, public health agencies and consumers. Issues that relate to the food industry and public health are beyond the scope of the present document. Consumers have an important responsibility in food safety. They may be increasingly concerned, but not knowledgeable about safe food preparation practices [22][23], and physicians can play a role in their education. Many consumers believe that foodborne illnesses are most often acquired outside of the home, whereas most infections actually occur in the home setting [24]. Factors contributing to these infections are contaminated raw food supplies, improper food handling, and intentional consumption of raw or undercooked foods of animal origin.

Consumers are eating more fresh fruits and vegetables and grains – foods that are recommended as part of a healthier diet. These foods may travel over great distances. The demand for fresh produce all year round has resulted in increasing consumption of produce imported from countries where the methods of production are not as well controlled as in Canada and, thus, where microbial contamination is more likely to occur [8][22]. It has been suggested that over 50% of fresh vegetables sold in the developed world are imported from developing countries [12].

Consumers are also using commercial meal services more often – at home or outside of the home. They frequently buy ready-to-eat take-out meals at grocery stores or restaurants. Preparation in bulk, and suboptimal storage or reheating may result in growth of pathogens in these foods [22].

Dietary choices that include rare meats or raw fish and seafood and rapid cooking methods, which do not heat food thoroughly, have become increasingly popular. Consumers need to be aware of the infection risks of these practices, and the need to ensure that the starting ingredients are safe [22].

Parents may erroneously assume that organic produce is free of risk. The risk of infection from organic produce is as high as the risk from nonorganic produce, and with some production conditions, the risk may be higher. Both types of produce must be prepared with care [25]-[27].

Exposure of food to a controlled source of low-dose ionizing radiation enhances food safety by eliminating most microbial pathogens. Parents may be concerned about the safety of irradiated foods. Properly irradiated food is nutritious and safe [28]-[30]. Those concerned about the risks of ingesting a radioactive substance should be reassured that irradiated food is not radioactive. However, irradiation does not rid food of all microbes and, thus, is not a substitute for appropriate food production, processing and preparation.

Counselling tips for safe food handling

Ten rules for safe food preparation [31][32]:

  • Choose foods that are safe. Unpasteurized milk and unpasteurized juices (unless freshly prepared immediately before consumption) are inherently unsafe and without a noticeably improved nutritional value. Fresh fruits and vegetables can be contaminated and should be washed carefully, especially if they are to be eaten uncooked.
  • Separate food to be eaten raw from food to be cooked. Keep uncooked meat, poultry, fish or seafood separate from foods that will be consumed uncooked (eg, fruits and vegetables). Cooked food can also become contaminated through casual contact with raw food. Contamination can be from direct contact or indirect contact via contaminated cutting utensils, chopping boards and unwashed hands. It is important to carefully wash hands, utensils, chopping boards and work surfaces before and after manipulating raw food. When barbecuing, do not place cooked meats back on the plate that held uncooked meats.
  • Hands should be washed carefully before starting food preparation. Hands should also be washed after handling raw food, especially meat and poultry. In addition, hands should be washed after any interruption in food preparation, especially for activities such as using the toilet, changing a diaper or touching a pet.
  • Cook meats, poultry, eggs and seafood thoroughly. Raw meat, particularly poultry, is often contaminated with pathogens. Cooking these foods until they are steaming hot will ensure that most of the microorganisms are destroyed. It is particularly important to cook ground beef thoroughly (until it is no longer pink on the inside and the juices run clear) because inadequately cooked ground beef can cause E coli O157:H7 enteritis and hemolytic-uremic syndrome. Special care is required to ensure meat is thoroughly cooked when barbecuing [33]. Salmonella may be acquired from undercooked chicken, which should not be raw near the bones. Eggs should be thoroughly cooked to prevent transmission of Salmonella.
  • Eat foods soon after they are cooked. Cooked foods should, whenever possible, be consumed as soon as possible after they are cooked. Setting foods aside to cool at room temperature before eating runs the risk of permitting the growth of residual microorganisms.
  • Store cooked foods appropriately. If food must be cooked in advance, it should be kept above 60°C, or rapidly cooled and stored below 4°C to avoid growth of residual microorganisms. Store leftovers in the refrigerator or freezer promptly. Safe storage practices are particularly important for susceptible populations such as infants, toddlers and immunocompromised individuals.
  • Reheat cooked foods adequately. If cooked food is to be reheated before consumption, an adequate temperature must be reached to destroy any microbial growth that may have occurred during storage. If a microwave oven is used, ensure that the food has reached a uniformly hot temperature.
  • Keep the kitchen meticulously clean. Food debris can sustain microbial proliferation. Clean all used dishes, utensils and other equipment promptly.
  • Protect foods from insects, rodents and other animals (including pets). These can be carriers of pathogenic microorganisms. Store nonperishable foods in closed containers in a safe place.
  • Always use safe water for food preparation. If in doubt about water quality, boil it.

Food safety for immunocompromised patients

Physicians should advise parents of children who are immunocompromised to be particularly vigilant. These children are at an increased risk of severe disease following the acquisition of foodborne microorganisms, including Salmonella, Toxoplasma, Cryptosporidium and Listeria. Therefore, special care should be taken in selecting and preparing foods for them. Uncooked foods that contain high microbial loads or that cannot be adequately cleaned should be avoided. Recommendations for preventing foodborne illnesses in individuals with immunodeficiency after hematopoietic stem cell transplantation [34] or due to HIV [35][36] have been published. Advice in these documents is also pertinent to patients who are immunocompromised because of other illnesses or therapy.

  • It is especially important that meats, including casseroles containing raw meat, be cooked to the appropriate temperatures [33]. A thermometer should be used to measure internal temperature. Meat patés and other meat spreads that require refrigeration may contain bacteria and should be avoided or heated before being consumed.
  • Caution should be taken with foods that may contain raw or undercooked eggs (eg, certain preparations of hollandaise sauce, salad dressings, homemade mayonnaise, homemade eggnog, uncooked cake or cookie batter). These should be avoided, unless it can be confirmed that they do not contain raw eggs.
  • Soft cheeses and cheeses to which live microbial cultures have been added should be avoided.
  • Fresh fruits and vegetables should be thoroughly washed, then peeled or cooked. Raw fruits and vegetables that cannot be peeled and cannot easily be washed (eg, raspberries and strawberries) should be avoided.
  • Raw seed sprouts should be avoided.

Additional information on food safety for families

INFECTIOUS DISEASES AND IMMUNIZATION COMMITTEE

Members: Robert Bortolussi MD (chair); Dorothy L Moore MD; Joan L Robinson MD; Élisabeth Rousseau-Harsany MD (board representative); Lindy M Samson MD
Consultant: Noni E MacDonald MD
Liaisons: Upton D Allen MD, Canadian Pediatric AIDS Research Group; Charles PS Hui MD, CPS Liaison to Health Canada, Committee to Advise on Tropical Medicine and Travel; Nicole Le Saux MD, Immunization Program, ACTive; Larry Pickering MD, American Academy of Pediatrics, Red Book Editor and ex-officio member of the Committee on Infectious Diseases; Marina I Salvadori MD, CPS Liaison to Health Canada, National Advisory Committee on Immunization
Principal author: Dorothy L Moore MD


References

  1. Canadian Paediatric Society, Infectious Diseases and Immunization Committee [Principal author: G Delage]. Bugs in our meal: Food for thought. Paediatr Child Health 2001;6:214-7.
  2. Centers for Disease Control and Prevention. Foodnet reports. http://www.cdc.gov/foodnet/reports.htm (Version current at October 21, 2008).
  3. Public Health Agency of Canada. C-EnterNet. http://www.phac-aspc.gc.ca/c-enternet/index.html (Version current at October 21, 2008).
  4. Marwick C. Putting money where the US mouth is: Initiative on food safety gets under way. JAMA 1997;277:1340-2.
  5. Centers for Disease Control and Prevention (CDC). Preliminary FoodNet data on the incidence of infection with pathogens transmitted commonly through food – 10 states, 2007. MMWR 2008;57:366-70.
  6. Scallan E. Activities, achievements, and lessons learned during the first 10 years of the Foodborne Diseases Active Surveillance Network: 1996-2005. Clin Infect Dis 2007;44:718-25.
  7. Käferstein FK, Motarjerni J, Bettcher DW. Foodborne disease control: A transnational challenge. Emerg Infect Dis 1997;3:503-10.
  8. Tauxe RV. Emerging foodborne diseases: An evolving public health challenge. Emerg Infect Dis 1997;3:425-34.
  9. Bryan FL. Reflections on a career in public health: Evolving foodborne pathogens, environmental health, and food safety programs. J Environ Health 2002:65:14-24.
  10. Public Health Agency of Canada. C-EnterNet 2006 annual report. National Integrated Enteric Pathogen Surveillance Program. Version current at October 21, 2008.
  11. Morris JG Jr, Potter M. Emergence of new pathogens as a function of changes in host susceptibility. Emerg Infect Dis 1997;3:435-41.
  12. Scott E. Food safety and foodborne disease in 21st century homes. Can J Infect Dis 2003;14:277-80.
  13. Lindsay JA. Chronic sequelae of foodborne disease. Emerg Infect Dis 1997;3:443-52.
  14. Rowe PC, Orrbine E, Lior H, Wells GA, McLaine PN. A prospective study of exposure to verotoxin-producing Escherichia coli among Canadian children with hemolytic uraemic syndrome. The CPKDRC co-investigators. Epidemiol Infect 1993;110:1-7.
  15. Rangel JM, Sparling PH, Crowe C, Griffin PM, Swerdlow DL. Epidemiology of Escherichia coli O157:H7 outbreaks, United States, 1982-2002. Emerg Infect Dis 2005;11:603-9.
  16. Will RG, Ironside JW, Zeidler M, et al. A new variant of Creutzfeldt-Jakob disease in the UK. Lancet 1996;347:921-5.
  17. Beisel CE, Morens DM. Variant Creutzfeldt-Jakob disease and the acquired and transmissible spongiform encephalopathies. Clin Infect Dis 2004;38:697-704.
  18. Schlech WF III. Foodborne listeriosis. Clin Infect Dis 2000;31:770-5.
  19. Marcus R. New information about pediatric foodborne infections: The view from FoodNet. Curr Opin Pediatr 2008;20:79-84.
  20. American Academy of Pediatrics. Appendix VI. Clinical syndromes associated with foodborne diseases. In: Pickering LK, ed. Red Book: 2006 Report of the Committee on Infectious Diseases. 27th edn. Elk Grove Village: The American Academy of Pediatrics 2006:857-60.
  21. Health Canada. Food and Nutrition. Advisories, Warnings and Recalls. http://www.hc-sc.gc.ca/fn-an/advisories-avis/index_e.html (Version current at October 21, 2008).
  22. Collins JE. Impact of changing consumer lifestyles on the emergence/reemergence of foodborne pathogens. Emerg Infect Dis 1997;3:471-9.
  23. Bruhn CM. Consumer concerns: Motivating to action. Emerg Infect Dis 1997;3:511-5.
  24. Public Health Agency of Canada. Canadian Integrated Surveillance Report: Salmonella, Campylobacter, pathogenic E. coli and Shigella, from 1996 to 1999. CCDR 2003;29(S1). http://www.phac-aspc.gc.ca/publicat/ccdr-rmtc/03vol29/29s1/index.html (Version current at October 21, 2008).
  25. Heuer OE, Pedersen K, Andersen JS, Madsen M. Prevalence and antimicrobial susceptibility of thermophilic Campylobacter in organic and conventional broiler flocks. Lett Appl Microbiol 2001;33:269-74.
  26. Dixon B. Natural might not be healthier. Lancet Infect Dis 2001;1:360.
  27. Phillips CA, Harrison MA. Comparison of the microflora on organically and conventionally grown spring mix from a California processor. J Food Prot 2005;68:1143-6.
  28. Shea KM. Technical report: Irradiation of food. Committee on Environmental Health. Pediatrics 2000;106:1505-10.
  29. Tauxe RV. Food safety and irradiation: protecting the public from foodborne infections. Emerg Infect Dis 2001;7:516-21.
  30. Osterholm MT, Norgan AP. The role of irradiation in food safety. N Engl J Med 2004;350:1898-901.
  31. Pan American Health Organization. The WHO Golden Rules for Safe Food Preparation. http://www.paho.org/English/DD/PED/te_gold.htm (Version current at October 21, 2008).
  32. World Health Organization. Five keys to safer food. http://www.who.int/foodsafety/publications/consumer/5keys/en/index.html (Version current at October 21, 2008).
  33. Canadian Partnership for Consumer Food Safety Education. http://www.canfightbac.org/en/ (Version current at October 21, 2008).
  34. Centers for Disease Control and Prevention. Guidelines for preventing opportunistic infections among hematopoietic stem cell transplant recipients: Recommendations of CDC, the Infectious Disease Society of America, and the American Society of Blood and Marrow Transplantation. MMWR 2000;49(RR-10):48-52. http://www.cdc.gov/mmwr/PDF/rr/rr4910.pdf (Verison current at October 21, 2008).
  35. Centers for Disease Control and Prevention. Guidelines for preventing opportunistic infections among HIV-infected persons – 2002: Recommendations of the U.S. Public Health Service and the Infectious Diseases Society of America. MMWR 2002;51(RR-8):49. http://www.cdc.gov/mmwr/PDF/rr/rr5108.pdf (Version current at October 21, 2008).
  36. Centers for Disease Control and Prevention. Caring for someone with AIDS at home. http://www.cdc.gov/hiv/pubs/brochure/careathome.htm (Version current at October 21, 2008).

Disclaimer: The recommendations in this position statement do not indicate an exclusive course of treatment or procedure to be followed. Variations, taking into account individual circumstances, may be appropriate. Internet addresses are current at time of publication.

Last updated: Apr 1 2016