Although the design of the bottle retort bag seems simple, it is very technologically advanced:

Outer layer:

Usually made of high-temperature resistant polyester film (BOPET), which has good printing properties, can be marked with instructions for use, and can withstand high temperatures during microwave heating without deformation.

Middle layer:

The key high barrier layer ensures that steam does not leak and can also effectively block external pollution.

Inner layer:

Food-contact-grade, high-temperature-resistant, heat-sealed polypropylene (PP) or polyethylene (PE). This material comes into direct contact with sterilized items and water, ensuring it will not release harmful substances at high temperatures and possessing excellent heat-sealing properties to ensure a tight closure.

Design details:

Zip Seal:

This is one of the most critical features. It allows parents to easily open and seal the bag, ensuring that the steam is completely locked inside the bag while preventing the bag from bursting due to pressure during heating.

Water level indication:

The bag will usually clearly indicate the amount of water that needs to be added (usually 60ml or 90ml). Adding too much or too little water will affect the amount of steam generated and the disinfection effect.

Steam vent/breathing hole (optional):

Some designs include a tiny controlled breathable area in the corner of the bag to release a small amount of excess pressure, but in no way affects the sterile environment inside.