Using mẻ — a traditional Vietnamese sour rice fermentation — in home cooking can add delicious flavour and digestive benefits. But if it’s made or stored incorrectly, it can become a risk for your digestive system and even for your long-term health.

✅ Benefits of Mẻ When Used Properly

1. Enhances flavor & tenderises food
   Mẻ gives a mild sourness that heightens the taste of many traditional dishes. It also helps soften meat or fish, making the food easier to chew and digest. This can be especially helpful for older people or those with weaker teeth.

2. Fermented food with probiotic potential
   Traditional Vietnamese studies show that fermented plant or cereal foods contain lactic acid bacteria (LAB) and other beneficial microbes, which may support gut health and immunity. juniperpublishers.com+1 Mẻ falls into this category — when made safely, it may contribute to a healthier gut microbiome.

⚠️ But: It Can Turn Harmful If Made or Stored Wrong

• When the fermentation conditions are unsanitary, mẻ can harbour harmful bacteria, moulds or toxins. Some moulds produce mycotoxins which are carcinogenic, hepatotoxic or nephrotoxic. PMC

• People with sensitive digestion, chronic stomach/intestinal disease, immune-compromised conditions should use caution. Fermented foods may cause gas, bloating, or, in rare cases, food-borne illness. Cultures For Health

🙋‍♂️ People Who Should Be More Careful

• Those with gastric/intestinal disorders, gastritis, ulcers — as acidic fermented condiments may worsen irritation.

• Individuals on low-sodium diets (because many traditional ferments use salt for preservation).

• Pregnant women, young children, immune-compromised persons — always check preparation hygiene and quantity.

🛠 Tips for Safe Use & Production of Mẻ

• Use a clean ceramic, glass, or glazed clay jar for fermentation — avoid plastic, as some plastics may leach chemicals during fermentation.

• The rice used should be clean, not mouldy or old; rinse well, cook (if necessary) and cool correctly.

• After filling the jar/ferment vessel, cover it properly and store in a cool, dry, well-ventilated place.

• Check the mẻ before use: if you see unusual mold colours (green/black/bright), strong foul odour, large gas build-up → discard immediately.

• When using mẻ in cooking: apply in modest amounts, combine with hygienic ingredients and cook well.

📝 Summary for Your Household

Mẻ is a traditional condiment with both potential benefits (enhanced taste, improved digestion, probiotic effect) and risks (if unsafely prepared or used indiscriminately). The key is hygiene, moderation, and being aware of your body’s response. If your family uses mẻ often, make it safely or buy from trusted sources — don’t assume “traditional = always safe”.