What Is the Best Packaging for Fresh Produce? A Guide to Types and Benefits

• Various packaging and materials exist for transporting, storing, protecting, and displaying fresh produce.
• Different packaging is suitable for specific fresh produce.
• Modified Atmosphere Packaging that alters the inside atmosphere is most successful in maintaining quality and freshness and extending shelf life.
• A well-researched material choice and specific gas mixture are necessary for efficient MAP packaging of fresh produce.

Choosing the correct packaging type and material for fresh produce, whole and cut, is a critical decision that will influence quality, shelf life, and appeal. It is also vital in bringing and selling fresh produce from farms to consumers. Over 1500 types of packages are used for fresh produce in the USA. This number keeps increasing as new and more efficient packaging is introduced. In this article, you will find the standard packaging methods for fresh produce.

Purpose of Packaging

Figure 1: Main functions of fresh produce packaging, adapted from WUR. (Image credits: Wageningen University and Research)

Packaging is necessary for fresh produce to transport, store, and sell the perishable products in the supply chain. Packaging performs several purposes, as shown in Figure 1, and these are discussed below:

• Maintain quality and extend shelf-life: Fresh produce is prone to moisture and weight loss, ethylene effects, and spoilage. Packaging can control or reduce the fruit’s physiological processes that are responsible for these losses to maintain quality and extend shelf life. Packaging protects fresh produce from the external environment through light and oxygen.
• Ensure food safety: Packaging is a barrier against pests, pathogens, and chemical contamination. Specific gas mixtures used in modern modified atmosphere packaging also slow microbial growth and keep fresh produce safe.
• Increase sales appeal: Transparent packaging material can attract consumers who judge fresh produce quality by color and freshness. Also, the packaging can be colorful, with shapes, logos, etc., used to appeal to consumers.
• Containment: Packaging contains several items of the same or several species. The packaging is also designed to protect fresh produce from mechanical damage—for example, a bag of oranges or a tray of mixed berries.
• Provide information and labeling surface: The package provides a surface to give information on product weight, price, class and size, variety, ‘best-before date,’ and country of origin. Organic fresh produce is often packaged to separate from conventionally grown food, with labels to identify them.
• Offer convenience: Packaging is a convenient way to sell processed products ready for consumption, such as cut fruits and vegetable salads.
• Sustainability: Packaging can improve food sustainability by providing a means to extend the shelf-life of foods, increase economic returns, allow better distribution of food, and reduce food loss. Concerns of post-consumer waste, recyclability, and biodegradability of packaging material must, however, be addressed during the choice of type and amount of packaging.

The effectiveness of packaging will depend on choosing the right type for the intended use.

Types of Fresh Produce Packaging

Each packaging is made to perform specific functions, with advantages and disadvantages. Packaging is expensive, and given the numerous available options, it is essential to know their uses. Standardization is being introduced to reduce fresh produce packaging costs and increase reuse.

Wood pallets: Most fresh produce is transported with wood pallets, which have been used since the Second World War. There are no standard sizes, but the 40 x 48-inch pallet has become the unofficial standard. The pallets are covered with plastic netting to secure items, which can affect ventilation. So, low tensile glue is used to stabilize stacks of pallets.

Slipsheets: These are pallet-sized sheets with a lip on one or more sides made of a combination of materials, fiberboard, or plastic. These are easier to store and reuse and are less expensive than pallets.

Pallet Bins: Wooden pallet bins help transport fresh produce from fields to packing houses and can carry 12-50 bushels. The popular base dimensions are the same as pallets 48 x 40 inches, with variations in heights. The pallet bins are locally made, reusable, lasting five to 10 years.

Wire-Bound Crates: Wooden wire-bound crates are commonly used for fresh produce that needs hydrocooling, such as sweet corn, snap beans, etc. These large-scale packages are rigid, sturdy, and can be stacked. Various sizes, from half a bushel to pallet size, are available, with ample ventilation and cooling openings. The reuse rate is less, but it can be easily dissembled for remanufacture.

Wooden lugs and crates: Wooden crates were traditionally used for potatoes, stone fruits, and apples. Lugs are still used for grapes and other specialty items and are made to hold 15 to 25 pounds. The wooden crates and lugs are expensive and heavy and add weight, so alternative materials are used for long-distance transport of tropical fruits.

Wooden baskets: Wire-reinforced baskets and hampers of varying sizes were standard for vegetables and fruits. They are durable and easily stored. However, the cost and disposal problems have limited their use to only local markets.

Corrugated fiberboard: These are used for bulk transport of potatoes, melons, cabbage, citrus, etc., to processors and retailers. Usually called cardboard, these come in various sizes and styles, are low cost, and versatile. Their strength increases, and the grades are differentiated by weight and thickness. They are being made from recycled fibers. Labeling is easy for these packaging. The disadvantage is that low temperatures, moisture from fresh produce, and high humidity reduce their strength by 75% unless the containers are specially treated with either wax or plastic. However, waxed and plastic-coated cartons are challenging to recycle and landfill.

Pulp containers: These are made from recycled paper pulp and are a staple for small consumer packages. Pulp containers come in various sizes and shapes, and standard

sizes are relatively inexpensive. Pulp containers absorb moisture from fresh produce and can be helpful in the case of berries and small fruits. These packages are recyclable and biodegradable.

Paper and mesh bags: Paper bags are now used only as consumer packs for potatoes and onions. Mesh bags are low-cost, allow airflow, and are used for all fresh produce. These also allow for the display of the food to appeal to consumers. Large bags are challenging to palletize and can be damaged due to rough handling. Moreover, mesh bags do not protect from contamination and light.

Plastic bags: Polyethylene bags have become the predominantly used consumer packaging of whole and cut fresh produce. It is transparent, makes food inspection easy, allows labeling, and is cheap. Depending on thickness and grade, it can extend shelf-life and have varying degrees of air movement. It is helpful for MAP packages. However, the single-use plastic waste pollution it generates is a major environmental concern.

Shrink wrap: Individual fresh produce items can be packaged in plastic shrink wrap to prevent water loss, respiration, diseases, and mechanical damage. They are transparent, allow the display of products, are easy to label, and are used for apples, cucumbers, sweet corn, tropical fruits, etc. Plastic wraps are also single-use plastics that increase waste volumes.

Plastic rigid packages: One or two-piece boxes in various shapes and sizes are used for high-value items like mushrooms and berries, cut produce, prepared salads, etc. They are light, cheap, and easy to label but are made from polystyrene, which is difficult to recycle. Their negative environmental impact is a significant disadvantage.

These packages can transport, store, and protect fresh produce. New developments like MAP that alter the packaging’s atmosphere in combination with plastic packaging are increasingly used to maintain quality and extend shelf-life.

MAP Packaging

Modified atmosphere packaging (MAP) is a technique to extend the shelf-life of perishable fresh produce and other food by altering the proportions of atmospheric gases in a suitable packaging material to slow physiological processes, microbial activity, and dehydration.

Controls physiology: It aims to slow down physiological processes that ripen, spoil, or decay fresh produce. Fresh produce continues to respire and transpire after harvest. They use oxygen to break down sugars and produce carbon dioxide (CO2). The heat released in the process causes moisture loss or fruit transpiration that hastens ripening and senescence, reducing shelf-life. Moreover, water loss due to fruit transpiration that increases due to heat released by respiration is also reduced. Changing oxygen levels reduces respiration and its impacts on fruit quality in MAP.

Limits microbial activity: Growth and reproduction of microbes like bacteria and fungi that spoil fresh produce are slowed in an altered atmosphere. Many microbes cause diseases and food poisoning, which MAP can reduce.

Prevents dehydration: MAP acts as a barrier to light and forms a protective covering that maintains a relative humidity of around 95%. Fresh produce has evolved to limit postharvest transpiration through a thick skin and cuticle layer. Some, however, have thin skin and will need artificial protection from transpiration that leads to wilting, weight loss, texture, and freshness.

Table 1: Recommended gas mixtures for fresh produce MAP packaging, Ščetar & Kurek (2010). (Credits: Croatian Journal of Food Technology, Biotechnology

and Nutrition 5 (3-4), 69-86 (2010))

MAP Principles

The various methods through which MAP is achieved are as follows:

Altered atmosphere

The gases whose proportions are altered in MAP are oxygen, carbon dioxide, and nitrogen.

• Oxygen (O2) levels are reduced to bring down respiration rates.
• CO2 levels are increased to limit the oxidation of fresh produce tissue and the growth of microbes.
• Nitrogen is an inert gas used as filler with O2 and CO2.

The ambient gas is removed and filled with an altered atmosphere. If the filled gases are in the targeted proportion, it is called passive MAP. Active MAP packages factor in the lower respiration rates, which continue to occur, to achieve the correct balance of O2 and CO2 in the parcel. The recommended gas proportions for MAP for various fresh produce are listed in Table 1.

Material selection

Selecting packaging with the correct gas permeability properties to maintain or achieve the optimal air composition is necessary to keep the target gas mixture and prevent dehydration. Usually, plastic is used. However, these days, researchers are trying to find more environmentally friendly material that is easy to recycle and biodegrade. Many are designed to have unique properties like ethylene scavenging to reduce the ripening and decay of items.

Cool storage

The storage temperature of MPA packages is also crucial. MAP packages are usually stored and kept in cool temperatures of 2-4°C, except for some tropical fruits that can suffer cold injury and must be over 10°C.

The benefits of MAP are associated with having a suitable atmosphere. However, since precise conditions are required, some problems can occur.

MAP Malfunctions

MAP packaging without the correct gas mix or temperature can lead to fermentation or oxidation.

• Fermentation occurs when O2 levels are too low, and CO2 levels or temperatures increase, leading to anaerobic respiration and decay.
• Oxidation occurs when the temperature is too low, or the packaging material is very permeable, allowing ambient O2 in.

Both issues cause different types of discoloration. The decay causes odor, alters taste, and spoils products. Fixing these issues by checking at critical points in the supply chain is possible. To prevent packaging contamination, hygienic conditions are also necessary for all packaging, including MAP.

Checking for Problems

To maintain optimum MAP conditions, conducting regular checks of the following issues is essential:

• Check gas content: Measure the concentrations of the two leading headspace gases, O2 and CO2, in the MAP packages to spot leaks or fluctuations from the standard target gas mixture.
• Check seals and openings: This check is made in packing houses to ensure no food is present in the seal line, as it leaves openings, allowing undesired gas exchange.
• Check the external atmosphere: Check the temperature and relative humidity of the storage facility.

Different devices are available for these checks, though seals and openings can also be controlled manually.

How to Check Headspace Gas Mixtures

The analysis must be done with sealed packages to read MAP gas mixtures accurately. Felix Instruments offers many precision instruments that can be used to measure headspace atmosphere:

• The F-920 Check It! Gas Analyzer that measures O2 and CO2 levels simultaneously.
• The F-950 Three Gas Analyzer and F-940 Store It! Gas Analyzer for three gas analyses- O2, CO2, and ethylene in the headspace.
• The F-960 Ripen It! Gas Analyzer is used for a high-resolution measurement of ethylene, along with O2 and CO2 for ripening packages.

All the tools are easy to use and require no extra skills. The results are available in real-time and accurate and can be stored on a USB for data transfer. The small and portable tools are helpful for the supply chain, from packing houses to retailers, to check gas mixtures.

Contact us for more information about our precision gas analyzers.

Sources

Czerwiński, K., Rydzkowski, T., Wróblewska-Krepsztul, J., & Thakur, V. K. (2021). Towards Impact of Modified Atmosphere Packaging (MAP) on Shelf-Life of Polymer-Film-Packed Food Products: Challenges and Sustainable Developments. Coatings, 11(12), 1504. https://doi.org/10.3390/coatings11121504

 

Eagri.org. (n.d.). Chapter 9: Various methods of packaging- packaging materials and transport. Retrieved from http://eagri.org/eagri50/HORT381/pdf/lec09.pdf.

 

Ščetar, M., & Kurek, M. (2010). Trends in fruit and vegetable packaging–a review. Hrvatski časopis za prehrambenu tehnologiju, biotehnologiju i nutricionizam, 5(3-4), 69-86.

 

Wageningen University and Research. (n.d.). Packaging of fresh produce. Retrieved from

https://www.freshknowledge.eu/en/increase-your-knowledge/how-to-maintain-quality-of-fresh-produce/packaging-of-fresh-produce.htm#Overview_most_important_packag-anchor