Prepared, packaged, and fermented foods are generally safe when stored properly and eaten before their expiration date. The main risks come from cross-contamination and temperature abuse — food left out too long, or pre-made deli-style salads (chicken salad, tuna salad, ham salad) sitting at deli counters, which the FDA treats similarly to deli meat for Listeria risk if they haven't been kept properly refrigerated. Fermented foods like kimchi, sauerkraut, and kombucha are generally fine in moderation; unpasteurized kombucha specifically contains live cultures and a small trace of alcohol from fermentation, which is why some providers suggest choosing pasteurized versions or limiting intake. Fermented foods can also be a source of beneficial probiotics, and there's no established need to avoid them during pregnancy beyond the same general storage and freshness precautions that apply to any prepared food.
The caution around this food applies consistently across all three trimesters — there isn’t a specific window during pregnancy where it becomes more or less risky. The safest approach is moderation and attention to preparation or portion size throughout, rather than avoiding it in some trimesters and not others. If you’re managing a related condition, such as gestational diabetes or high blood pressure, ask your provider whether they’d recommend a stricter limit than the general guidance described here.