The Challenge: Why Freshness Degrades After Harvest
The moment a fruit or vegetable is harvested, the clock starts. Without the plant’s root system supplying water and nutrients, the product begins consuming its own reserves. Respiration continues. Enzymes activate. Moisture escapes. Microbial activity accelerates.
For fresh produce, the journey from field to retail shelf can span anywhere from two to ten days, depending on whether the product travels domestically or overseas. During that window, exposure to oxygen, temperature fluctuations, and physical handling all contribute to quality loss.
Industry estimates suggest that roughly 13% of crops are lost between harvest and retail. Without effective packaging interventions, that number would be significantly higher.
This is the problem Modified Atmosphere Packaging is engineered to address.
What Is Modified Atmosphere Packaging
Modified Atmosphere Packaging (MAP) is a preservation technique that alters the gas composition inside a sealed package to slow biological degradation. By reducing oxygen levels and adjusting the balance of carbon dioxide and nitrogen, MAP creates an internal environment that decelerates respiration, limits oxidation, and inhibits microbial growth.
Unlike vacuum packaging, which removes air entirely, MAP maintains a carefully controlled gaseous environment tailored to the specific commodity. The goal is not to eliminate respiration, but to moderate it.
There are two primary approaches to achieving a modified atmosphere:
- Gas flushing: Air is mechanically displaced and replaced with a predetermined gas mixture (typically CO₂ and N₂) before sealing.
- Natural equilibrium MAP: The package is sealed under normal atmospheric conditions, and the product’s own respiration, combined with the film’s permeability, gradually establishes a stable internal atmosphere.
Both methods have applications depending on the commodity, supply chain length, and performance requirements.
How MAP Works Across Real Distribution Timelines
Understanding MAP requires understanding the realities of produce logistics.
From Field to Packing House
After harvest, produce typically reaches a packing facility within 6 to 24 hours. During this window, respiration rates are high, and the product is most vulnerable to moisture loss and temperature stress.
Domestic Transport
For produce moving within a single country, transit times range from two to six days. Temperature control during this phase is critical, but packaging must also maintain atmospheric integrity despite stacking, vibration, and handling.
International Shipping
Overseas shipments can extend transit to four to seven days or longer. At this scale, even small inconsistencies in film permeability or seal integrity can result in measurable quality degradation by the time the product reaches its destination.
MAP packaging must perform reliably across all of these phases. A film that functions well in controlled storage but fails under the physical stresses of transport does not solve the real problem.
The Role of Oxygen, Moisture, and Respiration
Three factors drive the majority of post-harvest quality loss in fresh produce:
Oxygen
Oxygen fuels respiration and enzymatic browning. Elevated oxygen levels accelerate the breakdown of sugars and acids, leading to flavor loss, texture degradation, and reduced shelf life. However, reducing oxygen too aggressively can trigger anaerobic respiration, producing off-odors and accelerating spoilage.
The target is balance: enough oxygen to maintain aerobic respiration at a reduced rate, but not so much that degradation accelerates.
Moisture
Fresh produce is largely water. As moisture escapes through the packaging, products lose weight, turgor, and visual appeal. Wilting, shriveling, and surface desiccation are all symptoms of inadequate moisture retention.
Effective MAP films must control moisture transmission without trapping excess humidity, which can promote microbial growth and surface decay.
Respiration
Different commodities respire at different rates. Leafy greens respire faster than root vegetables. Tropical fruits behave differently than temperate-climate produce. A MAP film that works well for spinach may not be appropriate for carrots.
This is why film selection cannot be generic. The oxygen transmission rate (OTR) of the packaging material must be matched to the respiration rate of the specific product.
Why Material Selection Matters in MAP Performance
The film is the control mechanism. Its permeability determines how gases move in and out of the package. Its mechanical properties determine whether the package survives handling. Its consistency determines whether performance is repeatable across production runs.
Oxygen Transmission Rate (OTR)
OTR defines how much oxygen passes through the film over time. A film with an OTR that is too high will fail to establish a modified atmosphere. A film with an OTR that is too low may create anaerobic conditions.
Precise OTR control, calibrated to the commodity, is essential.
Puncture and Abrasion Resistance
Fresh produce is not uniform. Stems, edges, and surface textures can stress packaging materials during filling, sealing, and transport. A film that punctures easily introduces uncontrolled oxygen ingress, negating the benefits of MAP.
Materials must withstand the physical realities of agricultural handling.
Batch-to-Batch Consistency
In high-volume operations, inconsistency is a liability. If OTR varies from roll to roll, shelf life predictions become unreliable. Quality control becomes reactive rather than preventive.
Consistent manufacturing processes translate directly to consistent field performance.
Where Nylon MAP Films Are Particularly Effective
Nylon (polyamide) films have established a role in MAP applications where durability, controlled permeability, and mechanical strength are priorities.
Compared to commodity films, nylon offers:
- Superior puncture resistance: Critical for produce with sharp stems or abrasive surfaces
- Controlled oxygen transmission: Nylon films can be engineered to specific OTR targets
- Dimensional stability: Maintains performance under temperature variation during transport
- Abrasion resistance: Withstands the friction of stacking, palletizing, and automated handling
Nylon MAP films are used in harvest bags, liners, form-fill-seal applications, and custom perforated configurations. They are particularly suited for operations where packaging failure during transit would result in significant product loss.
Where M&Q MAP Films Fit
M&Q manufactures coextruded nylon MAP films at its facility in Schuylkill Haven, Pennsylvania. The company is the only North American manufacturer that both extrudes and converts nylon MAP films in a vertically integrated operation.
Key characteristics of M&Q MAP films include:
- FDA-compliant, Grade A resins
- Precisely controlled oxygen transmission rates
- High clarity for product visibility and inspection
- Formats available in tube stock, pouches, liners, and form-fill-seal films
- Low-volume options suitable for seasonal or specialty crops
M&Q’s engineering team supports custom formulations for applications where standard OTR profiles do not meet commodity-specific requirements.
For operations where supply chain reliability and material consistency are priorities, U.S.-based manufacturing reduces lead time variability and simplifies vendor qualification.
Selecting the Right MAP Film for Your Application
Choosing a MAP film is not a generic decision. It requires matching material properties to commodity respiration, transit duration, handling conditions, and regulatory requirements.
Questions to consider:
- What is the respiration rate of the commodity?
- What is the expected transit time and temperature range?
- What physical stresses will the package encounter during handling?
- What OTR is required to achieve the target internal atmosphere?
- What certifications (FDA, FSSC 22000, etc.) are required for the application?
Technical data sheets, sample testing, and engineering consultation are standard steps in the qualification process.
Request technical data for MAP applications or discuss film requirements with our engineering team.
