Risks from the nylon film wrapped inside gio lua

Lining the banana leaf with nylon film speeds up gio production and retains moisture, but it poses a chemical leaching risk if the wrong type of plastic is used.

Many production facilities currently add an extra layer of nylon film, tightly wrapping the meat inside the green banana leaf when making gio lua. According to chef Vu Nhat Thong (Eric Vu Cooking Class Center), this technique is popular due to four advantages:

Waterproofing: The process of boiling or steaming gio lasts for hours. Banana leaves can easily have gaps, allowing water to seep in and make the gio bland and spoil quickly. A tightly wrapped nylon film prevents this.

Hygiene: The plastic layer prevents the gio's surface from direct contact with the leaves, limiting microorganisms and dirt if the banana leaves are not thoroughly cleaned.

Moisture Retention: The film prevents evaporation, making the gio juicier and heavier, which increases profits for sellers.

Packaging Speed: Wrapping gio entirely with banana leaves requires skilled workers. Using plastic film allows for quick shaping in mass production, at which point the outer banana leaves are mainly for aesthetics.

While offering production benefits, this film can affect food quality and consumer health. According to chef Thong, the gio will be safe if facilities use food-grade Polyamide (PA) or PA/PE film. This type of plastic withstands temperatures above 100 degrees Celsius without needing plasticizers, and is commonly used in vacuum sealing and slow cooking technologies.

Conversely, if thin PE film or recycled plastic is used, chemical leaching can occur. PE plastic typically begins to soften at 90 degrees Celsius. When heated to 100 degrees Celsius for about one hour in a fatty environment from the meat, chemicals from the film can easily transform and leach into the food.

To ensure health and traditional flavor, the chef recommends that home cooks avoid using plastic film directly wrapping the meat. They only need to thoroughly wash the banana leaves, blanch them in boiling water for 10-15 seconds or lightly char them to soften, then wrap three overlapping layers and tie them tightly. This technique helps prevent water from entering and preserves the banana leaf's aroma.

If plastic film is desired for easier shaping, cooks should let the banana leaves tightly wrap the meat first, then wrap heat-resistant film on the outermost layer. This allows the banana leaves to prevent fat from contacting the plastic, while the film provides waterproofing.

For consumers, peeling a cooked gio is a quick way to check the film's quality. If the film is tough, clear, and smooth, the producer has used good heat-resistant plastic. If the film is thin, shriveled, opaque, or has an unusual smell, buyers should switch suppliers.