Packaging Fresh and Chilled Produce: Methods and Materials

Fresh fruits and vegetables are among the most perishable food products in the world. According to the Food and Agriculture Organization (FAO), postharvest losses of produce in developing countries can reach as high as 50 percent for some commodities. The difference between produce that arrives fresh at the consumer’s table and produce that ends up in the waste bin often comes down to one critical factor – packaging. The right packaging system can slow down biological deterioration, prevent physical damage, and keep fruits and vegetables looking and tasting their best for days or even weeks longer than unpackaged produce.

Why fresh produce needs specialised packaging 🔗

Unlike processed or canned foods, fresh fruits and vegetables are living organisms that continue their metabolic activities even after being harvested. They keep consuming oxygen, releasing carbon dioxide, losing moisture, and producing heat through respiration. Since they can no longer replenish their food and water reserves from the parent plant, these ongoing processes gradually deplete stored energy and lead to ageing, decay, and eventual spoilage.

Packaging for fresh produce, therefore, has a very different job from packaging for shelf-stable products. It must manage the biological activity of the product itself while simultaneously protecting it from external threats. A well-designed package considers the specific physiology of each commodity and creates an environment that slows deterioration as much as possible.

Key challenges in packaging fresh and chilled produce 🔗

Before exploring the different packaging materials and methods, it helps to understand the four main challenges that packaging must address. Each of these factors directly influences how quickly produce loses quality after harvest.

Respiration 🔗

Respiration is the process by which produce breaks down stored sugars and starches using oxygen to release energy, carbon dioxide, and water vapour. This process generates heat and accelerates ageing. The higher the respiration rate, the shorter the shelf life. For instance, leafy greens and broccoli respire at much higher rates than apples or potatoes, making them far more perishable. Packaging must allow for adequate gas exchange – too little oxygen causes fermentation and off-flavours, while too much oxygen speeds up deterioration. As the NC State Extension notes, every fresh fruit and vegetable has its own requirements for temperature, humidity, and gas composition, and produce containers should maintain an optimal environment for the longest shelf life.

Moisture loss (transpiration) 🔗

Fresh produce contains 65 to 95 percent water. After harvest, water continues to evaporate from the surface through transpiration, leading to wilting, shrivelling, weight loss, and a loss of firmness. Leafy vegetables like spinach and lettuce lose water rapidly because they have thin skins with many pores. Root vegetables like potatoes, with their thicker skin, lose moisture more slowly. Packaging needs to maintain high relative humidity around the produce to minimise water loss without creating conditions that encourage microbial growth from excess condensation.

Microbial decay 🔗

Fungi, bacteria, and other microorganisms are the primary biological agents of postharvest spoilage. Common pathogens such as Botrytis, Penicillium, Rhizopus, and Alternaria cause rots that can spread quickly, especially when produce is bruised or stored in warm, humid conditions. Packaging helps by acting as a physical barrier against external contamination and, in some cases, by creating an internal atmosphere that inhibits the growth of spoilage organisms.

Physical and mechanical damage 🔗

Bruising, cuts, abrasion, and compression are extremely common during harvest, transport, and retail handling. Damaged produce not only looks unappealing but also respires faster and becomes an easy entry point for pathogens. Good packaging provides structural support, cushioning, and separation to prevent individual items from pressing against or rubbing on each other during the supply chain journey.

Packaging materials commonly used for fresh produce 🔗

The packaging industry has developed a wide range of materials specifically tailored to meet the needs of fresh fruits and vegetables. The choice of material depends on the type of produce, the distance it needs to travel, the storage duration, and the point of sale – whether wholesale, retail, or direct-to-consumer.

Flexible plastic films 🔗

Flexible plastic films are among the most widely used packaging materials for fresh produce. Common types include low-density polyethylene (LDPE), polyvinyl chloride (PVC), polypropylene (PP), and cellulose acetate films. These films can be manufactured in a wide range of thicknesses and engineered with specific gas permeability properties to manage the atmosphere around the produce.

Many of these films are used as pouches with perforations punched at regular intervals to allow for gas exchange during respiration. According to NC State Extension’s produce packaging guide, film bags are clear, easy to inspect, and accept high-quality graphics. They can also be engineered to “breathe” at rates necessary to maintain the right balance of oxygen, carbon dioxide, and water vapour inside the bag – a feature that has been central to the growth of pre-cut and bagged salad products.

Trays with overwraps 🔗

This packaging format combines a rigid or semi-rigid tray – made from moulded pulp, PVC, PP, or expanded polystyrene – with an overwrap film that holds the produce in place. Individual items sit in shaped cavities within the tray, which prevents bruising and abrasion during transport. The overwrap film provides additional protection, retains moisture, and can be designed with specific permeability characteristics.

Trays with overwraps are commonly used for items like tomatoes, stone fruits, kiwis, and mushrooms. Shrink films made from materials such as polypropylene or polyethylene can also be used as overwraps – once applied and passed through a heat tunnel, the film tightens around the tray, immobilising the produce and reducing the risk of physical damage during handling.

Plastic punnets (clamshells) 🔗

Punnets are small, rigid plastic containers – typically made from polyethylene terephthalate (PET) – that are widely used for berries, cherry tomatoes, grapes, and other small or delicate fruits. They feature snap-on or hinged lids and strategically placed ventilation holes that allow air circulation while maintaining some humidity control.

The rigid walls of punnets protect fragile produce from crushing, and their transparency allows consumers to inspect the product before purchase. While they are inexpensive and versatile, environmental concerns about single-use plastic waste have prompted the industry to explore recyclable and biodegradable alternatives.

Corrugated fiberboard boxes 🔗

Corrugated fiberboard remains the dominant material for wholesale and transport packaging of fresh produce. These boxes are made by sandwiching a layer of corrugated paperboard between inner and outer liners (facings) of kraft paper. The result is a lightweight but sturdy container that provides excellent protection during shipping and can be printed with branding and product information.

Corrugated boxes are recyclable and cost-effective compared to alternatives like wood, glass, or plastic crates. They are often lined with plastic films or fitted with inserts to create optimal conditions for specific produce types. Wax-coated versions are available for items that need hydrocooling or high-humidity storage. However, moisture can weaken uncoated fiberboard, reducing stacking strength by up to 75 percent – so choosing the right coating or treatment is essential for cold-chain applications.

Other packaging formats 🔗

Beyond the main categories above, several other packaging materials serve specific roles in the fresh produce supply chain:

Foam sleeves are tubular polyethylene foam pieces that slip over individual fruits (like apples or pears) to provide cushioning against abrasion and scratches during transport. Net bags made from mesh are popular for onions, potatoes, cabbage, and citrus, offering good airflow at very low cost. Moulded pulp trays, made from recycled paper, are biodegradable and absorb surface moisture – making them particularly suitable for berries and small fruits. Wooden crates and lugs, though less common today, are still used for grapes and some specialty produce.

Modified atmosphere packaging (MAP) 🔗

Among all the packaging technologies available for fresh produce, modified atmosphere packaging (MAP) stands out as one of the most effective methods for extending shelf life. MAP works by altering the composition of gases inside the sealed package to create conditions that slow down the produce’s metabolic activity and delay spoilage.

How MAP works 🔗

The atmosphere inside a MAP package is adjusted to contain specific proportions of oxygen (O₂), carbon dioxide (CO₂), and nitrogen (N₂) – different from the normal atmospheric composition of roughly 21% O₂, 0.04% CO₂, and 78% N₂. For most fresh produce, the target is to reduce oxygen levels and increase carbon dioxide levels compared to normal air. According to a review published on ScienceDirect, typical MAP gas mixtures for produce contain O₂ concentrations in the range of 1-10% and CO₂ concentrations in the range of 1-20%, with nitrogen filling the remaining space.

Reducing oxygen slows down the respiration rate, conserves stored energy, and delays ripening. Elevated carbon dioxide further suppresses respiration and also inhibits the growth of many spoilage microorganisms. Nitrogen serves mainly as a filler gas to prevent pack collapse. The specific gas mixture must be tailored to each commodity – what works for lettuce can be harmful to strawberries.

Passive vs. active MAP 🔗

There are two approaches to establishing the desired atmosphere inside a package. In passive MAP, the produce’s own respiration gradually depletes oxygen and accumulates carbon dioxide within a sealed package made from a film with carefully selected permeability. Over time, an equilibrium atmosphere develops based on the balance between the produce’s respiration rate and the film’s gas transmission rate. This approach is commonly used for fresh respiring fruits and vegetables and is the simpler, lower-cost method.

In active MAP, the desired gas mixture is introduced directly into the package – either by vacuuming out the existing air and flushing with the target gas blend, or by using a lance (snorkel) system that replaces the air as the package is sealed. Additionally, active MAP may use scavengers or absorbers placed inside the package – for example, iron-based oxygen scavengers, potassium permanganate-based ethylene absorbers, or calcium oxide-based CO₂ absorbers – to fine-tune and maintain the internal atmosphere throughout storage.

Benefits and considerations of MAP 🔗

Research consistently shows that MAP can extend the shelf life of fresh produce significantly – from several days to several weeks, depending on the commodity and storage temperature. Benefits include delayed ripening and softening, reduced browning, maintained nutritional quality, and decreased microbial spoilage. A review published in the journal Food and Bioprocess Technology highlights that MAP retards the respiration rate of fresh produce and delays enzymatic degradation.

However, MAP is not without its challenges. Excessive CO₂ levels (above 10% for many commodities) can be phytotoxic, causing tissue damage and off-flavours. If O₂ levels drop too low (below about 2%), anaerobic respiration kicks in, producing alcohol and undesirable odours. Temperature management is critical – MAP only works effectively when combined with proper refrigeration, since higher temperatures increase respiration rates and can throw off the carefully designed atmospheric balance. The packaging film must be matched precisely to the specific produce type, taking into account its respiration rate, the pack weight, storage temperature, and distribution conditions.

The role of temperature in produce packaging 🔗

No packaging system, however advanced, can compensate for poor temperature management. Refrigeration is the single most important factor in extending the shelf life of fresh fruits and vegetables. Low temperatures reduce respiration rates, slow ethylene production, limit microbial growth, and decrease moisture loss.

Packaging and cold chain management work together. Corrugated fiberboard boxes, for example, are designed with ventilation openings (typically covering 5-7% of the face area) to allow cold air to reach the produce during forced-air cooling while maintaining structural strength for stacking. MAP systems are designed around specific storage temperatures – if a package engineered for storage at 4°C is instead kept at room temperature, the respiration rate increases dramatically, O₂ is depleted faster than the film can replace it, and the entire system can fail.

Sustainability trends in fresh produce packaging 🔗

Environmental concerns are reshaping how the produce industry thinks about packaging. Single-use plastics, while functionally excellent, create enormous waste. The industry is increasingly moving toward recyclable, biodegradable, and compostable alternatives.

Promising developments include packaging made from plant-based materials like bamboo, hemp, and palm leaves, which are biodegradable and require less energy to produce than petroleum-based plastics. PLA (polylactic acid), derived from corn starch or sugarcane, is being used for trays and containers. Edible packaging made from seaweed or starch-based films is also gaining attention, though challenges around durability and cost remain.

Smart packaging technologies that incorporate freshness sensors, QR codes for traceability, and IoT-enabled monitoring systems represent another frontier. These systems can track temperature, humidity, and gas concentrations in real time, alerting supply chain participants to any conditions that might compromise quality.

Choosing the right packaging for different produce 🔗

There is no one-size-fits-all solution in fresh produce packaging. The right choice depends on the specific characteristics of the commodity, the intended storage duration, the distribution chain, and the target market. Here are some general guidelines:

Berries and small fruits benefit from rigid plastic punnets or clamshells that prevent crushing, combined with ventilation for airflow. Leafy greens and salad mixes perform best in MAP bags with carefully engineered film permeability. Root vegetables and tubers like potatoes and onions do well in mesh or paper bags that allow airflow. Stone fruits, apples, and tropical fruits often use trays with overwraps or foam sleeves for individual protection. For wholesale transport, corrugated fiberboard boxes – sometimes lined with MAP-compatible films – remain the standard.

The key principle across all categories is that the packaging should be specifically matched to the produce’s physiology – its respiration rate, ethylene sensitivity, moisture requirements, and susceptibility to mechanical damage.

What do you think? How important is packaging in your own experience of buying fresh produce – do you notice a difference in shelf life between packaged and loose items? And as sustainable packaging materials develop further, do you think consumers will accept potential trade-offs in convenience or cost for the sake of reducing plastic waste?

References

1. https://www.fao.org/4/t0073e/t0073e01.htm
2. https://en.wikipedia.org/wiki/Post-harvest_losses_(vegetables)
3. https://content.ces.ncsu.edu/introduction-to-the-postharvest-engineering-for-fresh-fruits-and-vegetables/9-produce-packaging
4. https://pmc.ncbi.nlm.nih.gov/articles/PMC7089433/
5. https://felixinstruments.com/blog/what-is-the-best-packaging-for-fresh-produce-a-guide-to-types-and-benefits/
6. https://www.sciencedirect.com/topics/food-science/modified-atmosphere-packaging
7. https://en.wikipedia.org/wiki/Modified_atmosphere
8. https://www.amcor.com/insights/blogs/modified-atmosphere-packaging
9. https://www.fruitnet.com/fruitnet/comment-fresh-produce-packaging-trends-for-2025/264357.article
10. https://www.mdpi.com/2304-8158/14/3/447