Covering up food to keep it safe- The world of food packaging

Packaging food the right way
Covering up food to keep it safe- The world of food packaging
Photo - Claudia Gonzalez

The purpose of packaging is to ensure the containment, convenience, traceability, and marketing of food products. It also conveys to consumers important facts like nutritional and ingredient information, best-before dates, manufacturing address, and much more. Product-specific packaging reduces food wastage by extending the shelf life of foods. Owing to new developments like the rise in consumer demand to know about their food’s journey, trends like traceability are gaining importance. By incorporating unique codes on the packaging material, manufacturing companies can track their products throughout the journey from farm to fork. Hence, the role of packaging in the food business cannot be downplayed.

The construction and design of packaging material play an integral part in determining the product’s shelf life. During storage and distribution, an apt packaging material ensures the safety and freshness of the product. A few packaging materials used in the food industry are discussed below.

Glass - Being inert with almost all food products and odorless, glass is useful in packaging them without impacting their organoleptic properties. It is also useful while sterilizing low and high-acid foods since glass can withstand high processing temperatures. Glass is also impermeable to gases and vapors and thus maintains the freshness of products for a long time. Glass fosters sustainability since it is recyclable and reusable as well.

However, glass poses some issues, like increased transportation costs due to its heavy weight, susceptibility to breakage owing to impact, internal pressure or heat shock, and brittleness.

Glass is used to pack products such as coffee, spices, spices, spreads, syrups, and jams.

Metal - Metal can be considered the most versatile packaging material. It has been used for hundreds of years. Tin and Aluminium are the popular metals used to pack food and beverages in cans. Metal cans offer various benefits, such as good thermal conductivity, high mechanical strength, and resistance to high temperatures. These properties allow for the in-container thermal processing of cans. Aluminium offers a barrier to light, moisture, air, temperature, and chemical attack. It is mainly used in foils and cans and has good flexibility. Tinplate can be used for sterile products as it can be treated with heat and hermetically sealed.

Metal packaging can include cans, caps, and lids for glass jars, wraps, and bottles. Tinplate is widely used to make cans for drinks and processed foods and containers for powdered foods and sugar, among others.

Tin and Aluminium are entirely recyclable but have a higher carbon footprint than other materials like flexible packaging. Often, these cans need to be appropriately cleaned to remove the food, labels, and adhesives. This directs them to landfills which is an undesirable fate.

Plastic - The popularity of using plastics in the food packaging industry stems from the fact that they are lightweight, inexpensive, and can be molded into sheets and shapes, allowing flexibility in design. They also offer a range of optical and physical properties. The type of plastics used in food packaging is thermoplastics because they can be molded to form jugs, plastic films, and bottles. Many plastics allow easy printing and heat sealability and can be a part of the production line where the package is formed, filled, and sealed. Approximately 70% of plastic production is done by seven types of plastic polymers, some of which include Polyethylene Terephthalate (PET), High-Density Polyethylene (HDPE), Polyvinyl Chloride (PVC), Low-Density Polyethylene (LDPE), Polypropylene (PP) and Polystyrene (PS).

PET is more inert when compared to other plastics and finds use in making bottles for water, juice, alcoholic drinks, and soft drinks. HDPE is light in weight and opaque and is used in food storage containers, vinegar bottles, and chocolate syrups. With good resistance to oily substances, gases, and moisture, PVC is used in blister packaging for chewing gums and strawberry boxes. Frozen foods, bread, fruits, and vegetables are packed in LDPE packaging. Salad dressing bottles, yogurt bottles, and plastic bottle caps are made from PP and PS finds use in making disposable cups, plates, bakery trays, and plastic bottles, among others.

Despite some safety concerns, such as residual monomer and condensation components like bisphenol A, plastic use continues to rise due to its various benefits, like microwave ability, numerous shapes and sizes, optical properties, and heat seal ability.

Paper and paperboard - Since the 17th century, paper and paperboard have been used as packaging material, gaining momentum in the late 19th century. It is a 100% recyclable and eco-friendly material. Plain paper cannot protect food for a long time due to poor barrier properties and lack of heat sealability. When used in contact with food, paper is always treated, laminated, coated, or filled with resins and waxes to improve its protective properties. For instance, Kraft paper is produced by sulfate treatment, greaseproof paper undergoes beating to become gelatinous, glassine undergoes extreme hydration to get a smooth, glossy finish, and parchment paper is made from pulp with acid. Kraft and sulfite pulp are also used to make paper laminates that have improved gas and barrier properties.

Paperboard is thicker than paper and made in multiple layers. It finds its use in shipping containers like cartons, trays, and boxes and rarely in direct food contact. It may be of various types, like a whiteboard (bleached chemical pulp), solid board (bleached sulfate board), chipboard (made from recycled paper), and fiberboard (solid or corrugated).

Paper and paperboard are commonly used in milk cartons, corrugated boxes, wrapping papers, tissue paper, and paper plates. Paper laminates find use in packing soups, herbs, and spices.

Paper packaging offers benefits like foldability, low density, ability to be glued with adhesives, medium for low-cost printability, and good resistance to high and low temperatures. However, it provides hardships to manufacturers, too, owing to its permeability to water, organic solvents, gases, and aromas.

Choosing a suitable material for packaging

Food manufacturers have an ocean of options to choose from when it comes to packaging. However, choosing the appropriate packaging material that suits the properties of the product that is to be packed is of utmost importance. For instance, chocolates need to be packed to reduce the impact of temperature fluctuations to prevent fat or sugar bloom, wine and dairy products need to be safe from light penetration to prevent photo-oxidation, and so on.

To choose the suitable packaging material for their product, manufacturers need to keep in mind the food’s characteristics and the packaging material’s expected functions. Some of the essential points to focus on are listed below.

  • Requirement of protection from light, oxygen, or breakage (for fragile products)

  • Need for additional functions like vacuum packaging, antioxidant addition, processing in package (canning), or convenience (heating of food in the container,single-serve, and so on)

  • Location of the product

  • Refrigerated display- Fit, form, and function to be considered

  • Freezer/ frozen food case- Packaging performance to be monitored

  • Heated display case- Limited options; ventilation is important

  • Reduction of inventory space

  • Increasing the number of units per space for more sales

  • Optimization of space within the packaging to fit more products

  • Reduce the overall packaging cost

  • Opt for a less expensive material with the same function

  • For single servings, keep a higher price point

Other considerations

  • Type of packaging or filling equipment required by the product

  • Type of packaging used for similar products

Preventing printing ink migration from packaging material to the food

An unintentional hazard to the food in direct contact with the packaging occurs through a process known as ink migration. It exposes the food to the ink and poses a safety risk to the consumer’s health. This can happen when moisture enters the printed substrate during storage, usually when packaging is stored in rolls. This causes the ink to migrate from the printed to non printed side, and the potentially toxic inks come in contact with foods. Ink particles might also leach into the food through the exterior packaging owing to the condensation or evaporation from the foods within the packaging.

Some steps that can be taken to prevent ink migration are discussed below.

Migration testing and risk assessment

The risk of migration for the packaging and labels need to be carried out, especially for packaging where an absolute barrier is absent. Additionally, calculation of worst-case scenarios, practical migration tests, and taste and odor testing also help.

Assessment of material

To prevent food contamination, all the materials used throughout the packaging manufacturing process should be assessed. When a press is converted from conventional printing ink to low migration ink, the press should be thoroughly cleaned to avoid contamination from previously used high migration ink.

Use of inks and coatings for food-safe packaging

When the food is separated from packaging material by one or more layers, the barrier and migration properties of the packaged food determine the suitability of those inks and coatings. Low migration inks need to be tested to ensure they stay within the standardized acceptable limits.

Reduction in the UV/EB ink migration

Drying or curing of printing inks may be done using ultraviolet radiation technology or electron beam technology. Proper curing is necessary to meet the UV and EB needs for food packaging and labels, requiring apt lamp power, print speed, and ink film thickness.

The food packaging industry is on the rise with innovations to provide varied packaging designs, convenience, and utility for the end users. Companies also conduct life cycle analyses of their packaging material to determine its environmental impact. Further, product-specific packaging enhances the food’s shelf life and consumer acceptance while preserving its organoleptic properties. It can be concluded that the food packaging market is on an exciting journey and walks hand in hand with the numerous food developments that cannot sustain without appropriate packaging to store them.

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