Food safety during pregnancy

While we were happy to see the issue of food safety during pregnancy addressed in the April 2010 Motherisk Update,¹ we were also concerned about some of the information in the article contradicting public health messages on this topic.

The authors state there is increased incidence of disease or severe outcomes for the woman or neonate. However, they also recommend that foods that might contain Listeria monocytogenes (eg, deli meats, soft cheeses), Salmonella (eg, eggs), or various bacteria, viruses, and parasites (eg, raw fish) are safe for consumption if properly handled and stored and purchased from reputable suppliers. These statements appear to contradict each other and are not supported by the literature and public health recommendations.^2–5

The authors do not provide references for many of their statements or else, in certain instances, use references that are out of date or not representative of Canada. Nonpublished literature (eg, government documents, guidelines) and content experts have not been consulted to identify recent Canadian outbreaks, public health programs, and messages related to this topic.

The authors suggest that improved standards and surveillance have reduced the prevalence of contaminated foods in grocery stores and that the frequency of outbreaks has decreased. It is not possible to say whether the prevalence of contaminated foods and frequency of outbreaks have decreased. Some literature suggests that the number of outbreaks and the incidence of Salmonella and Listeria are increasing.^6,7 Outbreaks and food recalls⁸ related to listeriosis and deli meats^9,10 or soft cheeses,^11,12 as well as salmonellosis and eggs,^7,13 continue to occur.

Food stored in a refrigerator allows the growth of Listeria, which prefers to multiply at these temperatures.¹⁴ Proper storage therefore increases the risk of listeriosis. Proper handling of food (eg, washing hands) is recommended; however, foods such as deli meats and cheeses might already be contaminated when purchased. The consumer does not typically take additional steps at home (eg, cooking) to reduce potential pathogens in such foods. Although purchasing food from a reputable supplier with approved food safety plans is a good suggestion, even reputable suppliers can have problems on account of the ubiquitous nature of these pathogens in a food processing environment.^9,10 Additionally, it is not possible for a pregnant woman to identify foods that have been prepared or stored appropriately in restaurants and outside of the home (eg, flash-frozen sushi, refrigerated eggs).

Finally, the authors have made some unfounded recommendations. The Public Health Agency of Canada and most provincial, territorial, and local public health authorities in Canada as well as in many other countries recommend the following^3,4,15,16:

• Pregnant women should avoid consuming unpasteurized milk and dairy products, soft cheeses (both pasteurized and unpasteurized), deli meats, and smoked fish owing to the potential risk of listeriosis. Such foods can only be safely eaten if heated to 74°C (165°F).

• Pregnant women and the general population should avoid consuming raw and undercooked eggs. They should store eggs in the refrigerator and wash their hands as well as any utensils or surfaces after contact with raw eggs. The use of pasteurized egg products is recommended when a recipe calls for raw eggs.

• Pregnant women and the general population should be aware that consuming raw fish, shellfish, or raw bivalves (eg, oysters) increases the risk of Vibrio, noro-virus, and other food-borne infections.

Research has shown that health care providers might not provide sufficient information about risks associated with food safety to pregnant women and that messages should be improved and targeted.^2,17–19 There is ongoing work in Canada to address this.

Motherisk is a valuable and credible source of information for pregnant women and their health care providers. However, as evidenced by this article¹ and another published² in the same issue of Canadian Family Physician, further work is needed to improve food safety knowledge among pregnant women and their health care providers.