FOOD PACKAGING SUBJECT,

ANALYTICAL CHEMISTRY

INTRODUCTION :-

Advances in food processing and food packaging play a primary role in keeping the U.S. food supply among the safest in the world. Simply stated, packaging maintains the benefits of food processing after the process is complete, enabling foods to travel safely for long distances from their point of origin and still be wholesome at the time of consumption. However, packaging technology must balance food protection with other issues, including energy and material costs, heightened social and

environmental consciousness, and strict regulations on pollutants and disposal of municipal solid waste.

Packaging technology can be of strategic importance to a company, as it can be a key to competitive advantage in the food industry. This may be achieved by catering to the needs and wants of the end user, opening up new distribution channels, providing a better quality of presentation, enabling lower costs, increasing margins, enhancing product/brand differentiation, and improving the logistics service to customers.

The business drive to reduce costs in the supply chain must be carefully balanced against the fundamental technical requirements for food safety and product integrity, as well as the need to ensure an efficient logistics service. In addition, there is a requirement to meet the aims of marketing to protect and project brand image through value-added pack design. The latter may involve design inputs that communicate distinctive, aesthetically pleasing, ergonomic, functional and/or environmentally aware attributes.

Thus, there is a continual challenge to provide cost effective pack performance that satisfies the needs and wants of the user, with health and safety being of paramount importance. At the same time, it is important to minimize the environmental impact of products and the services required to deliver them. This challenge is continually stimulated by a number of key drivers – most notably, legislation and political pressure. In particular, there is a drive to reduce the amount of packaging used and packaging waste to be disposed of.

Roles of Food Packaging :-

The principal roles of food packaging are to protect food products from outside influences and damage, to contain the food, and to provide consumers with ingredient and nutritional

information (Coles 2003). Traceability, convenience, and tamper indication are secondary functions of increasing importance. The goal of food packaging is to contain food in a cost-effective way that satisfies industry requirements and consumer desires, maintains food safety, and minimizes environmental impact.

Protection :-

Food packaging can retard product deterioration, retain the beneficial effects of processing, extend shelf-life, and maintain or in-crease the quality and safety of food. In doing so, packaging provides protection from 3 major classes of external influences: chemical, biological, and physical.

Chemical protection minimizes compositional changes triggered by environmental influences such as exposure to gases (typically oxygen), moisture (gain or loss), or light (visible, infrared, or ultraviolet. Many different packaging materials can provide a Chemical barrier. Glass and metals provide an early absolute barrier to chemical and other environmental agents, but few packages are purely glass or metal since closure devices are added to facilitate both filling and emptying. Closure devices may contain materials that allow minimal levels of permeability. For example, plastic caps have some permeability to gases and vapors, as do the gasket materials used in caps to facilitate closure and in metal can lids to allow sealing after filling. Plastic packaging offers a large range of barrier properties but is generally more permeable than glass or metal.

Biological protection provides a barrier to microorganisms (pathogens and spoiling agents), insects, rodents, and other animals, thereby preventing disease and spoilage. In addition, biological barriers maintain conditions to control senescence (ripening and aging).Such barriers function via a multiplicity of mechanisms, including preventing access to the

product, preventing odor trans-mission, and maintaining the internal environment of the package.

Physical protection shields food from mechanical damage and includes cushioning against the shock and vibration encountered during distribution. Typically developed from paperboard and corrugated materials, physical barriers resist impacts, abrasions, and crushing damage, so they are widely used as shipping containers and as packaging for delicate foods such as eggs and fresh fruits. Appropriate physical packaging also protects consumers from various hazards. For example, child-resistant closures hinder access to potentially dangerous products. In addition, the substitution of plastic packaging for products ranging from shampoo to soda bottles has reduced the danger from broken glass containers.

Marketing and Information:-

A package is the face of a product and often is the only product exposure consumers experience prior to purchase. Consequently, distinctive or innovative packaging can boost sales in a competitive environment. The package may be designed to enhance the product image and/or to differentiate the product from the competition. For example, larger labels may be used to accommodate recipes. Packaging also provides information to the consumer. For example, package labeling satisfies legal requirements for product identification, nutritional value, ingredient declaration, net weight, and manufacturer information. Additionally, the package conveys important information about the product such as cooking instructions, brand identification, and pricing. All of these enhancements may impact waste disposal.

Convenience :-

Convenience features such as ease of access, handling, and disposal; product visibility; reseal ability; and microwavability greatly influence package innovation. As a consequence,

packaging plays a vital role in minimizing the effort necessary to prepare and serve foods. Oven-safe trays, boil-in bags, and microwavable packaging enable consumers to cook an entire meal with virtually no preparation. New closure designs supply ease of opening, reseal ability, and special dispensing features. For example, a cookie manufacturer recently introduced a flexible bag with a scored section that provides access to the cookies. A membrane with a peel able seal covers the opening before sale and allows re closure after opening. Advances in food packaging have facilitated the development of modern retail formats that offer consumers the convenience of 1-stop shopping and the availability of food from around the world. These convenience features add value and competitive advantages to products but may also influence the amount and type of packaging waste requiring disposal.

Tamper indication :-

Willful tampering with food and pharmaceutical products has resulted in special packaging features designed to reduce or eliminate the risk of tampering and adulteration. Although any package can be breeched, tamper-evident features cannot easily be re placed. Tamper-evident features include banding; special membranes, breakaway closures, and special printing on bottle liners or composite cans such as graphics or text that irreversibly change upon opening. Special printing also includes holograms that cannot be easily duplicated. Tamper-evident packaging usually requires additional packaging materials, which exacerbates disposal issues, but the benefits generally outweigh any drawback. An example of a tamper-evident feature that requires no additional packaging materials is a heat seal used on medical packaging that is chemically formulated to change color when opened.

Other functions:-

Packaging may serve other functions, such as a carrier for premiums (for example, inclusion of a gift, additional product, or coupon) or containers for household use. The potential for packaging use/reuse eliminates or delays entry to the waste stream.

Materials Used in Food Packaging :-

Package design and construction play a significant role in determining the shelf life of a food product. The right selection of packaging materials and technologies maintains product quality and freshness during distribution and storage. Materials that have traditionally been used in food packaging include glass, metals (aluminum, foils and laminates, tinplate, and tin-free steel), paper and paper boards, and plastics. Moreover, a wider variety of plastics have been introduced in both rigid and flexible forms. Today’s food pack ages often combine several materials to exploit each material’s functional o r aesthetic properties. As research to improve food packaging continues, advances in the field may affect the environmental impact of packaging.

Glass:-

Because it is odorless and chemically inert with virtually all food products, glass has several advantages for food-packaging applications: It is impermeable to gases and vapors, so it maintains products freshness for a long period of time without impairing taste or flavor. The ability to withstand high processing temperatures makes glass useful for heat sterilization of both low- acid and high-acid foods. Glass is rigid, provides good insulation, and can be produced in numerous different shapes. The transparency of glass allows consumers to see the product, yet variations in glass color can protect light-sensitive contents.

Finally, glass packaging benefits the environment because it is reusable and recyclable.

Metal’s:-

Metal is the most versatile of all packaging forms. It offers a combination of excellent physical protection and barrier properties, formability and decorative potential, recyclability, and consumer acceptance. The 2 metals most predominantly used in packaging are aluminum and steel.

Plastic:- Multiple types of plastics are being used as materials for packaging food, including polyolefin ,polyester ,polyvinylchloride ,polyvinylidene chloride, polystyrene, polyamide, and ethylene vinyl alcohol. Although more than 30 types of plastics have been used as packaging materials (Lau and Wong 2000), polyolefins and polyesters are the most common.

Paper:-

Plain paper is not used to protect foods for long periods of time because it has poor barrier properties and is not heat seal able. When used as primary packaging (that is, in contact with food), paper is almost always treated, coated, laminated, or impregnated with materials such as waxes, resins, or lacquers to improve functional and protective properties.

TYPES OF FOOD PACKAGING

Vacuum Packaging :-

Vacuum packing or vacuum packaging is a method of packaging that removes air from the package prior to sealing.

It can involve both rigid and flexible types of packaging. The intent is usually to remove oxygen from the container to extend the shelf life of foods and, with flexible package forms, to reduce the volume of the contents and package.[1]

Vacuum packing reduces atmospheric oxygen, limiting the growth of aerobic bacteria or fungi, and preventing the evaporation  of  volatile  components. It is also commonly used to store dry foods over a long period of time, such as cereals, nuts, cured meats, cheese, smoked fish, coffee, and potato chips (crisps). On a more short term basis, vacuum packing can also be used to store fresh foods, such as vegetables, meats, and liquids, because they inhibit bacterial growth.

Vacuum packing greatly reduces the bulk of non-food items. For example, clothing and bedding can be stored in bags evacuated with a domestic vacuum cleaner or a dedicated vacuum sealer. This technique is sometimes used to compact household waste, for example where a charge is made for each full bag collected.

Vacuum packaging products using plastic bags, canisters, bottles, or mason jars are available for home use.

Vacuum packaging delicate food items can be done by using an inert gas, such as nitrogen. This helps prevent crushing fragile items and delicate foods such as potato chips.

Modified Atmosphere Packaging:-

Gas atmosphere is modified by (1) direct injection of gases (often CO2 or nitrogen) into a package, (2) evacuating air from the package or (3) interaction between package contents and the air in the package causing the package atmosphere to modify over time. The latter is what happens with fresh fruit and vegetables. With proper packaging, the natural respiration of produce causes O2 levels to drop and CO2 levels to rise. Modified atmosphere packages have an atmosphere different from ambient air but, that atmosphere can change over time. In the case of produce, package atmosphere is affected by the transmission rates of the packaging material and changes in storage temperatures. Higher temperatures lead to higher respiration rates, creating lower O2 levels in the package atmosphere and higher concentrations of CO2. Hence, the atmosphere inside the package is modified but not controlled.

Modified atmosphere is the practice of modifying the composition of the internal atmosphere of a package (commonly food packages, drugs, etc.) in order to improve the shelf life.

The modification process often tries to lower the amount of oxygen (O2), moving it from 20.9% to 0%, in order to slow down the growth of aerobic organisms and the speed of oxidation reactions. The removed oxygen can be replaced with nitrogen (N2), commonly acknowledged as an inert gas, or carbon dioxide (CO2), which can lower the pH or inhibit the

growth of bacteria. Carbon monoxide can be used for preserving the red color of meat.

Re-balancing of gases inside the packaging can be achieved using active techniques such as gas flushing and compensated vacuum or passively by designing “breathable” films known as equilibrium modified atmosphere packaging (EMAP). Packets containing scavengers may be used.

Controlled Atmosphere Packaging:-

A defined Mix. Of gases is maintained or controlled over time by some external apparatus or internal chemical reactions. An example of a controlled atmosphere is the container (used for ocean transport of fruit) which have a mechanical means of measuring the container atmosphere and adjusting the gas levels to maintain a predetermined mixture of CO2, O2 and N2 during shipment. Placing an oxygen absorbing sachet inside a barrier package is an example of a controlled atmosphere package using a chemical reaction. The sachet absorbs any oxygen that transmits through the package barrier. Sulfur dioxide producing pads used in long term shipment or storage of table grapes to prevent growth of gray mold are another example of controlling package atmosphere.

A controlled atmosphere is an agricultural storage method. An atmosphere in which  oxygen, carbon dioxide and  nitrogen concentrations as well as  temperature  and  humidity are regulated.

Two major classes of commodity can be stored in controlled atmosphere :

1. Dry commodities such as grains, legumes and oilseed. In these commodities the primary aim of the atmosphere is usually to control insect pests. Most insects cannot exist indefinitely without oxygen or in conditions of raised (greater than approximately 30%) carbon dioxide. Controlled atmosphere treatments of grains can be a fairly slow process taking up to several weeks at lower temperatures (less than 15°C). A typical schedule for complete disinfestations of dry grain (<13% moisture content) at about

25°C, with carbon dioxide, is a concentration above 35%(v/v) carbon dioxide (in air) for at least 15 days.[1] These atmospheres can be created either by: adding pure gases carbon dioxide or nitrogen or the low oxygen exhaust of hydrocarbon combustion, or using the natural effects of respiration (grain, moulds or insects) to reduce oxygen and increase carbon dioxide Hermetic storage.[2]

2. Fresh fruits, most commonly apples and pears, where the combination of altered atmospheric conditions and reduced temperature allow prolonged storage with only a slow loss of quality.

ENVIRONMENTAL ISSUES:-

Are plastic food containers recyclable?

Plastic food containers cannot be recycled to make new food containers for sanitation reasons. But plastics used in the food industry can be recycled for other uses if they can be separated easily. For example, recycled PET plastic is used for carpet backing, fiberfill for sleeping bags or ski jackets, fiberglass tubs and shower stalls, paintbrush and appliance handles, floor tiles, and more. Recycled HDPE plastic is used for such things as trashcans, flowerpots, traffic cones, and plastic “lumber” for park benches, railroad ties, boat docks, and fences. Polystyrene can be recycled, but systems for doing this are not well established.

Solution

Although no packaging is the best choice of all, it is not always practical. The need for any packaging should be evaluated in the research, design and marketing stages of a product. The goal should always be to reduce unnecessary packaging. The bulk delivery of solids and liquids to food industries and bulk retail sales from bins (including hardware products, produce, house

wares, toys and other items) eliminate unnecessary packaging. Where the need for packaging exists, packaging should follow the 3R's hierarch.

Reduce is the most important of the 3R's. Packaging should be reduced prior to the manufacturing stage, by designing and marketing products for the first "R". This means reducing the number of layers, materials and toxins at source.

Reuse is second in importance. Packaging should be designed to be reusable, refillable, returnable and durable to the greatest extent possible.

Recycle is third in importance. Packaging should be designed to be recyclable and/or made with recycled content.

References:-

1) Richard Coles (2003), food packaging technology.

2) Kenneth Marsh (2007), Roles, Materials &Environmental issues, journal of food science.

3) Wikipedia.

Plastic food containers cannot be recycled to make new food containers for sanitation reasons.

But plastics used in the food industry can be recycled for other uses if they can be separated

easily. For example, recycled PET plastic is used for carpet backing, fiberfill for sleeping bags

Or ski jackets, fiberglass tubs and shower stalls, paintbrush and appliance handles, floor tiles,

and more. Recycled HDPE plastic is used for such things as trashcans, flowerpots, traffic

cones, and plastic “lumber” for park benches, railroad ties, boat docks, and fences.

Polystyrene can be recycled, but systems for doing this are not well established.

Rigid plastic containers must be identified by code numbers to assist in sorting for recycling:

#1.= PET (polyethylene terephthalate),

#2 = HDPE (high density polyethylene),

#3 = PVC (polyvinyl chloride),

#4 = LDPE (low density polyethylene),

#5 = P/P (polypropylene),

#6 = P/S (polystyrene),

#7 = other, including multi-layer.

ENVIRONMENTAL IMPACTS

what about degradable plastic packages?

Degradable plastic packages decompose over time from exposure to light, hydrolysis,

biological organisms such as fungi or bacteria, or some combination of environmental factors.

“Reduced Oxygen Packaging” (ROP) means:

(i) The reduction of the amount of oxygen in a package by removing oxygen; displacing oxygen

and replacing it with another gas or combination of gases; or otherwise controlling the oxygen

content to a level below that normally found in the ambient atmosphere (which is typically at 21%

oxygen content, ROP would therefore be less than 21% oxygen), and

(ii) A process that involves a food for which the hazards of Clostridium botulinum and Listeria

monocytogenes require control in the final packaged form.

Typical applications for ROP include:

“Vacuum Packaging” (VP) in which air is removed from a package of food and the package is

hermetically sealed so that a vacuum remains inside the package,

“Modified Atmosphere Packaging” (MAP) in which the atmosphere of a package of food is

modified so that its composition is different from air but the atmosphere may change over time due

to the permeability of the packaging material or the respiration of the food. Modified atmosphere

packaging includes: reduction in the proportion of oxygen, total replacement of oxygen, or an

increase in the proportion of other gases such as carbon dioxide or nitrogen,

“Controlled Atmosphere Packaging” (CAP) in which the atmosphere of a package of food is

modified so that until the package is opened, its composition is different from ambient air with

continuous control of the atmosphere, using oxygen scavengers or a combination of total

replacement of oxygen, non-respiring food, and impermeable packaging material,

“Cook Chill Packaging” (CCP) in which cooked food is hot filled into impermeable bags (usually

as part of a total system), where the air expelled and the bags are then sealed or crimped closed. The

bags are rapidly chilled and refrigerated at temperatures that inhibit the growth of psychotropic

pathogens, and,

“Sous Vide Packaging” (SVP) in which raw or partially cooked food is placed in a

hermetically sealed, impermeable bag, cooked in the bag, served or rapidly chilled and refrigerated at

temperatures that inhibit the growth of psychrotrophic pathogens.

.