A French Dip sandwich typically consists of sliced roast beef served on a French roll with a side of savory au jus for dipping. While the components are not prohibited during pregnancy, the preparation of the roast beef introduces a specific food safety risk. The primary concern is a bacterium that thrives in ready-to-eat meats that are not thoroughly heated. Therefore, consuming a cold or lukewarm French Dip carries a recognized risk.
The Primary Concern: Listeria and Deli Meats
The concern with cold roast beef is potential contamination with Listeria monocytogenes, which causes Listeriosis. Pregnant individuals are highly susceptible, being 10 to 20 times more likely to contract it due to natural immune system changes. Symptoms for the mother are often mild, resembling the flu.
However, the bacterium can cross the placenta, leading to severe consequences for the fetus. Listeriosis is linked to increased risks of miscarriage, stillbirth, and premature delivery. Newborns may also contract serious health problems like meningitis.
Since Listeria monocytogenes can grow even at refrigerator temperatures, any ready-to-eat deli meat, including pre-sliced roast beef, carries a risk. This risk persists unless proper heating measures are taken.
Temperature is Key: Ensuring Safe Preparation
The risk posed by Listeria monocytogenes can be eliminated through heat treatment, making the French Dip safe if prepared correctly. The bacteria are easily killed when exposed to sufficient heat. The roast beef must reach a high enough internal temperature throughout the entire slice of meat.
The recommended safe internal temperature for reheating deli meats is a minimum of 165°F (74°C). The meat must be heated until it is “steaming hot” just before consumption, which serves as a visual cue that the required temperature has been reached. When ordering at a restaurant, specifically ask for the roast beef to be thoroughly reheated until steaming.
If preparing the sandwich at home, a food thermometer should be used to confirm the 165°F temperature. This is especially important because uneven heating, such as from a microwave, can leave cold spots where bacteria may survive. Simply warming the meat or serving it lukewarm is not a sufficient safety measure.
Addressing Other Components: The Au Jus and Cheese
Other elements of the French Dip require a brief safety check, though they are less concerning than the meat itself. The accompanying au jus, the savory broth made from meat drippings, must also be served piping hot. If the au jus is used to heat the meat, it must be boiling hot to effectively raise the roast beef temperature to 165°F.
If the sandwich includes cheese, such as Provolone or Swiss, these are usually safe options. Hard and semi-soft cheeses are safe because their low moisture content inhibits bacterial growth. Furthermore, nearly all commercial cheeses in the United States are made with pasteurized milk, which kills harmful bacteria during processing.
Pregnant individuals should only avoid soft cheeses, such as unpasteurized Brie or Feta, unless they are cooked until steaming hot. The typical cheeses used in a French Dip are acceptable as long as they are pasteurized or heated until completely melted.