Leaf Respiration Sets the Film
Fresh-cut lettuce continues to respire after packaging. The leaves consume oxygen and release carbon dioxide, changing the atmosphere inside a sealed pouch.
This makes the film specification particularly important for refrigerated salads. A material that performs well for dry snacks may create unsuitable conditions for living produce.
Custom Salad Flexible Pouches are intended for appropriately specified fresh-cut greens, shredded vegetables and salad mixes. The film construction, gas transmission, moisture behavior and filling method must suit the actual product and its cold chain.
The objective is to support the intended product quality without treating the pouch as a substitute for food-safety controls.
Oxygen Transmission
The oxygen transmission rate (OTR) determines how readily oxygen passes through the packaging film.
For fresh produce, this property must be considered alongside the product's respiration rate, pack weight, exposed film area and storage temperature.
A film with insufficient oxygen transmission can allow oxygen levels inside the pouch to fall too far. Excessively high transmission may also be unsuitable for the intended product and quality target.
The correct atmosphere depends on the produce itself.
USDA research confirms that fresh-cut produce varieties have different respiration requirements and that film permeability must be matched to the product.
An oxygen-barrier specification that works for dried food should therefore not be transferred automatically to fresh salad packaging.
Perforation Requirements
Microperforation is one possible method of adjusting gas exchange when the base film does not meet the product's requirements.
The number, diameter and arrangement of perforations affect how gases and moisture move through the package.
Perforation is not automatically necessary for every salad. Some products may require a carefully specified film without perforations. Others may need a different permeability profile or a validated modified atmosphere packaging process.
The decision must account for the intended salad blend, filling conditions, shelf life and refrigeration requirements.
Any proposed perforation pattern should be assessed for the specific product before it becomes part of the manufacturing specification.















