Key Message: Once infected with foodborne pathogens, high-risk individuals such as pregnant women are more likely to develop severe symptoms and even life-threatening. Therefore, it is necessary to avoid eating high-risk foods. In addition, pregnant women should also be especially wary of Listeria to prevent suffocation of foetal development and even death.

Hormonal and immune changes during pregnancy can weaken a pregnant woman's immune system, making her more susceptible to foodborne illness from high-risk foods. On the other hand, the developing foetus is susceptible to some food-borne pathogens that do not cause symptoms in pregnant women. The well-known Listeria monocytogenes is the pathogen that harms this group and can seriously affect fetal development and even lead to death.

Listeriosis and High-risk Foods

Foods Worthy of Attention

Caffeinated drinks Caffeine is a central nervous system stimulant that occurs naturally in plants such as coffee beans, tea leaves, cocoa beans, and kola nut. Many foods and drinks are fortified with caffeine for its bitter taste and refreshing effect. Everyone's tolerance to caffeine is different. Excessive intake of caffeine can cause anxiety, rapid heartbeat, tremors, sleep disturbance, and upset stomach. Excessive intake of caffeine by pregnant women is more likely to lead to low birth weight. Pregnant women and lactating women should avoid excessive intake of caffeine. Even if drinking coffee with less caffeine or milk tea, they should pay attention to the drinking amount.
Fish and Methylmercury

Methylmercury is a metallic contaminant commonly found in larger predatory fish. If a woman ingests large amounts of methylmercury before and during pregnancy, the methylmercury may pass to the foetus through the placenta and hence causing damage the developing foetal nervous system.

Fish is nutritious and contains many essential nutrients, such as omega-3 fatty acids and high-quality proteins for foetal development. Eating a variety of fish is part of a healthy diet, but avoid large predatory fish such as shark, swordfish, sailfish, goldeneye and tuna (particularly bigeye and bluefin).

Folic acid Folic acid is a water-soluble vitamin B that can help preventing anaemia. Adequate intake of folic acid by women before and during early stage of pregnancy can prevent spina bifida (a neural tube defect) in the foetus. Foods rich in folate include green leafy vegetables (such as choy sum, broccoli, lettuce), green beans and dried beans, and some fruits (such as oranges, bananas).
Iodine Iodine is a mineral required for proper brain development and physical growth in foetuses and infants. Foods rich in iodine include various types of seaweed (e.g. kelp soup, seaweed for snacks), iodised salt (Note: Limit the total salt intake to no more than 5 grams or 1 teaspoon per day, which includes salt from sauces, seasonings, and other foods), seafood (e.g. saltwater fish, prawns,  mussels), eggs, and milk and dairy products (e.g. cheese, yoghurt).

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