Product Quality
Factors affecting product quality and shelf life For many foods, the product shelf life is limited by specific or key attributes key attributes that can be predicted at the time of product development. This is either on the basis of experience with similar products or observations of them, or from a consideration of the make-up of the product (intrinsic factors,the environment that it will encounter during its life (extrinsic factorsand the shelf life limiting processes that processes that this combination of intrinsic and extrinsic factors is likely to result in. !ntrinsic factors are the properties resulting from the make-up of the final product and include the following" •
water activity (a (aw (available water
p#$total acidity% type of acid
• •
natural microflora and surviving microbiological counts in final product
•
availability of oxygen
redox potential ( E E h • natural biochemistry$chemistry of the product •
added preservatives (e.g. salt, spices, antioxidants • product formulation •
•
packaging interactions (e.g. tin pickup, migration.
&election of raw materials is important for controlling intrinsic factors, since subsequent processing can rarely compensate for poor-quality raw materials..'xtrinsic materials..'xtrinsic factors are a result of the environment that the product encounters encoun ters during life and include the following" •
timetemperature profile during processing
•
temperature control during storage and distribution
•
relative humidity ()# during storage and distribution
•
exposure to light (*+ and !) during storage and d istribution
•
composition of gas atmosphere within packaging
•
consumer handling.
Food-packaging interactions influencing quality and safety. !nteractions between foods and packaging can be detrimental to quality and$or safety. hanges in product flavor due to aroma sorption and the transfer of undesirable flavours from packaging to foods are important mechanisms of deterioration when foods are pack aged in polymer-based
materials. areful consideration must be given to those factors affecting such interactions when selecting packaging materials in order to maximie product quality, safety, and shelf-life while minimiing undesirable changes. roduct considerations include sensitivity to flavor and related deteriorations, color changes, vitamin loss, microbial activity, and amount of flavor available. &torage considerations include temperature, time, and processing method. olymer considerations include type of polymer and processing method, volume or mass of polymer to product ratio /ethodology to determine the extent of such interactions must be developed. 0irect interactions between food and packaging are not necessarily detrimental. The same principles governing undesirable interactions can be used to affect desirable outcomes. 'xamples include films which directly intercept or absorb oxygen, inhibit microorganisms, remove undesirable flavors by sorption, or indicate safety and produc t shelf-life.
Food 1uality Food quality is the quality characteristics of food that is acceptable to consumers. This includes external factors as appearance (sie, shape, color, gloss, and consistency, texture, and flavor% factors such as federal grade standards (e.g. of eggs and internal (chemical, physical, microbial.Food quality is an important food manufacturing requirement, because food consumers are susceptible to any form of contamination that may occur during the manufacturing process. /any consumers also rely on manufacturing and processing standards, particularly to know what ingredients are present, due to dietary, nutritional requirements (kosher , halal, vegetarian, or medical conditions (e.g., diabetes, or allergies.2esides ingredient quality, there are also sanitation requirements. !t is important to ensure that the food processing environment is as clean as possible in order to produce the safest possible food for the consumer. 3 recent example of poor sanitation recently has been the 4556 7orth 3merican '. coli outbreak involving spinach, an outbreak that is still under investigation after new information has come to light regarding the involvement of ambodian nationals. Food quality also deals with product traceability, (e.g., of ingredient, and packaging suppliers, should a recall of the product be required. !t also deals with labeling issues to ensure there is correct ingredient and nutritional information. There are many existing international quality institutes testing food products in order to indicate to all consumers which are higher quality products. Founded in 8968 in 2russels, The international quality institute. /onde &election is the oldest one in evaluating food quality. 0uring the degustation, the products must meet the following selection criteria, required by the !nstitute" sensory analysis, bacteriological and chemical analysis, the nutrition and health claims, and the utiliation notice. !n short, the :udgments are based on the following areas" taste, health, convenience, labeling, packaging, environmental friendliness and innovation.
'xample"
Shelf Life
&helf life is the length of time that a commodity may be stored without becoming unfit for use, consumption, or sale. !n other words, it might refer to whether a commodity should no longer be on a pantry shelf (unfit for use, or :ust no longer on a supermarket shelf. !t applies to cosmetics, foods and beverages, medical devices, medicines, explosives, pharmaceutical drugs, chemicals, car tires, batteries, and many other perishable items. !n some regions, an advisory best before, mandatory use by, or freshness date is required on packaged perishable foods. 2arrier packaging can often help control or extend shelf life. ;hen moisture content is a mechanism for product degradation, packaging with a low moisture vapor transmission rate and the use of desiccants help keep the moisture in the package within acceptable limits. ;hen oxidation is the primary concern, packaging with a low oxygen transmission rate and the use of oxygen absorbers can help extend the shelf life. roduce and other products with respiration often require packaging with controlled barrier properties. The use of a modified atmosphere in the package can extend the shelf life for some products. &ome active packaging is also available with antibacterial properties. Food shelf life and its importance for consumers. Food manufacturers are responsible for determining the shelf life and for labeling their products accordingly. This includes the storage conditions required to achieve that shelf life, for example s shelf life is typically determined during its development. !nitially, the manufacturer determines its characteristics (intrinsic and extrinsic, which affect its safety and$or quality. These characteristics include the ingredients used, the production process and the type of packaging, for example vacuum-packed or in a modified atmosphere, used to extend the product>s shelf life and the storage conditions where the product will be sold. The manufacturer may also conduct other studies such as sampling and microbiological analysis if deemed necessary. &helf life determination is an integral part of manufacturers>
shorten storage life. !f you don>t have a cool place for your food storage, plan on rotating your storage quickly enough to prevent food loss.
Factor 4" /oisture Foods with excess moisture can spoil in their containers. This is an important consideration when packing food with dry ice as moisture condenses and freees on the outer surface of the dry ice. For long-term storage, grains should have moisture content of 85C or less. !t is difficult to accurately measure this without special equipment. !t is also important to know that you can not dehydrate foods at home that reach these levels. Food that is dried to a moisture level of 85C moisture crisply snap when bent. Factor D" 3tmosphere Foods packed in air don>t store as well as in oxygen-free gasses. This is because air contains oxygen, which oxidies many of the compounds in food. 2acteria, one of several agents that makes food go rancid, also needs oxygen to grow. Food storage companies have a couple of different processes for removing oxygen" •
0isplacing oxygen" This is done by purging out all the air in the product with an inert gas. 7itrogen is almost always used because it is the most inert gas known. eople doing their own packing occasionally use dry ice which gives off carbon dioxide gas, and probably works :ust about as well.
•
3bsorbing oxygen" 3ir contains about EC nitrogen and 48C ox ygen, leaving about 8C for the other gasses. Axygen absorber packe ts leave about 99C pure nitrogen in a partial vacuum. !f oxygen absorber packets are used, care must be taken to use a storage container that can stand some vacuum.
Factor B" ontainer to get the best storage life out of your product it must have a hermetic (air tight seal. ontainers that do this well are" •
&ealable food storage buckets
•
&ealable food quality metal (lined or plastic drums
Active Packaging
The terms are closely related. 3ctive packaging usually means having active functions beyond the inert passive containment and protection of the product. Intelligent and smart packaging usually involve the ability to sense or measure an attribute of the product, the inner atmosphere of the package, or the shipping environment. This information can be communicated to users or can trigger active packaging functions. rogrammable matter , smart materials, etc. can be employed in packages. 0epending on the working definitions, some traditional types of packaging might be considered as GactiveG or GintelligentG. /ore often, the terms are used with new technologically advanced systems" microelectronics, computer applications, nanotechnology, etc. /oisture control For many years, desiccants have been used to actively control the water vapor in a closed package. 3 desiccant is a hygroscopic substance usually in a porous pouch or sachet which is placed inside a sealed package. They have been used to reduce corrosion of machinery and electronics and to extend the shelf life of moisture sensitive foods and drugs.
orrosion orrosion inhibitors can be applied to items to help prevent rust and corrosion. +olatile corrosion inhibitors (+! or vapor phase corrosion inhibitors can be provided inside a package in a pouch or can be incorporated in a saturated overwrap of special paper. /any of these are organic salts that condense on the metal to resist corrosion. &ome films also have +! emitting capability. Films are available with copper ions in the polymer structure, these neutralie the corrosive gas in a package and deter rust. +! create a neutral environment in the packaging. !t works on the principle of difference in vapor pressure and causes reaction with /etals and 7onmetals and also with /oisture to render it active to corrosion. There are different forms of +!Hs available like apers, lastics, #0' apers, Ails, Foams, hips, 3luminum 2arrier Foils, 2ubble, 'mitters etc. that can prevent corrosion at many stages. Axygen control Axygen scavengers or oxygen absorbers help remove oxygen from a closed package. &ome are small packets or sachets containing powdered iron" as the iron rusts, oxygen is removed from the surrounding atmosphere. 7ewer systems are on cards or can be built into package films or molded structures. !n addition, the physical characteristics of the packaging itself (oxygen transmission rate - AT) can dictate how effective an oxygen absorber can be, and how long it will stay effective. ackaging with a low AT) will let less oxygen in the closed package through the polymer barrier itself
3tmosphere ;ith some products, such as cheese, it has long been common to flush the package with nitrogen prior to sealing" the inert nitrogen is absorbed into the cheese, allowing a tight shrink film package. The nitrogen removes oxygen and GactivelyG interacts with the cheese to make the package functional. /ore recently, other mixtures of gas have been used inside the package to extend the shelf life. The gas mixture depends on the specific product and its degradation mechanisms. &ome package components have been developed that incorporate active chemistry to help maintain certain atmospheres in packages. Axygen scavengers, carbon dioxide generators, ethanol generators, etc. are available to help keep the atmosphere in a package at specified conditions. Temperature monitor &ome temperature indicators give a visual signal that a specified temperature has been exceeded. Athers, Time temperature indicators, signal when a critical accumulation of temperature
deviation over time has been exceeded. ;hen the mechanism of the indicator is tuned to the mechanism of product degradation, these can provide valuable signals for consumers. 0igital temperature data loggers record the temperatures encountered throughout the shipment. This data can be used to predict product degradation and help determine if the product is suited for normal sale or if expedited sale is required. They also determine the time of the temperature excess" this can be used to direct corrective action. Thermochromics inks are sometimes used to signal temperature excess or change. &ome are reversible while others have a permanent change of color. These can be used alone or with other packaging functions such as barcodes. The inks can also signal a desired temperature for consumers. For example, one type of beer can has ink that graphically shows when an ideal drinking temperature is achieved. ontrolling package temperatures For critical vaccines, insulated shipping containers are passive packaging to help control the temperatures fluctuations seen even with a controlled cold chain. !n addition, gel packs are often used to actively keep the temperature of the contents within specified acceptable temperature ranges. &ome newer packages have the ability to heat or cool the product for the consumer. These have segregated compartments where exothermic or endothermic reactions provide the desired effect. &elf are available for several products. 0ispensing &ome packages have closures or other dispensing systems that actively change the contents from a liquid to an aerosol. These are used for products ranging from precision inhalers for medications to spray bottles of household cleaners. &ome dispensing packages for two part epoxy adhesives do more than passively contain the two components. ;hen dispensed, some packages meter and mix the two components so the adhesive is fully functioning at the point of application. The ability of a package to fully empty or dispense a viscous liquid is somewhat dependent on the surface energy of the inner walls of the container. The use of super hydrophobic surfaces is useful but can be further improved b y using new lubricant-impregnated surfaces. )F!0 )adio-frequency identification chips are becoming more common as smart labels that are used to track and trace packages and unit loads throughout distribution. 7ewer developments include recording the temperature history of shipments and other intelligent packag ing functions.
&ecurity 3 variety of security printing methods, security holograms, and specialied labels are available to help confirm that the product in the package is not counterfeit. )F!0 chips are being used in this application also. 'lectronic (on the product or on the package is used to help counter shoplifting. /icrowave packaging /etallied films are used as a subsector for cooking in microwave ovens. These increase the heating capacity and help make foods crisp and brown. lastic microwavable containers are also used for microwave cooking. &hock and vibration &hock detectors have been available for many years. These are attached to the package or to the product in the package to determine if an excessive shock has been encountered. The mechanisms of these shock overload devices have been spring-mass systems, magnets, drops of red dye, and several others. )ecently, digital shock and vibration data loggers have been available to more accurately record the shocks and vibrations of shipment. These are used to monitor critical shipments to determine if extra inspection and calibration is required. They are also used to monitor the types of shocks and vibrations encountered in transit for use in package testing in a laboratory. 'xample"
Intelligent Packaging/Smart Packaging
I&martness> in packaging is a broad term that covers a number of functionalities, depending on the product being packaged, including food, beverage, pharmaceutical, household products etc. 'xamples of current and future functional Ismartness> would be in packages that J
)etain integrity and actively prevent food spoilage (shelf-life
J
'nhance product attributes (e.g. look, taste, flavor, aroma etc.
J
)espond actively to changes in product or package environment
J
ommunicate product information, product history or condition to user
J
3ssist with opening and indicate seal !ntegrity
J
onfirm product authenticity, and act to counter theft.
3ctive J
Axygen scavenging J
J
3nti-microbial
J
Kight protection (photochromic J
J
Time-temperature history /icrobial growth indicators
J
#eating$cooling
Adour and flavor absorbing$releasing J
J
'thylene scavenging J
J
!ntelligent
hysical shock indicators
Keakage, microbial spoilage indicating
/oisture absorbing 0ifference between smart and active packaging
#ow !ntelligent ackaging ;orks !n Iintelligent> packaging, the package function switches on and off in response to changing external$internal conditions, and can include a communication to the customer or end user as to the status of the product. 3 simple definition of intelligent packaging is Ipackaging which senses and informs>, and nowhere does this generate a more potent vision than within the smart home of the future.
!ntelligent ackaging for Fresh Fruit and +egetables Fresh-cut produce continues to be one of the fastest growing segments of food retailing and while conventional film packaging is suitable for lettuce and prepared salads, it cannot cope with the high respiration rates of pre-cut vegetables and fruit, leading to early product deterioration. !n the *&3, novel breathable polymer films are already in commercial use for fresh-cut vegetables and fruit. Kandec orporation supplies !ntellipac packaging films that are acrylic side-chain crystallisable polymers tailored to change phase reversibly at various temperatures from 5-6@. 3s the side-chain components melt, gas permeation increases dramatically, and by further tailoring the package and materials of construction, it is possible to fine tune the carbon dioxide to oxygen permeation ratios for particular products. The final package is Ismart> because it automatically regulates oxygen ingress and carbon dioxide egress by transpiration according to the prevailing temperature. !n this way, an optimum atmosphere is maintained around the product during storage and distribution, extending freshness and allowing shipping of higher quality products to the consumer. &elf-#eating and &elf-hilling ackaging !mproved convenience is a value-added function that customers are likely to pay extra for as lifestyles change. &elf-heating packages, for soup and coffee, for example, and self-cooling containers for beer and soft drinks have been under active development for more than a decade, but have yet to achieve commercial status. #owever, rown ork L &eal is pioneering the development of a self-chilling beverage can in con:unction with Tempra Technologies and development is nearing completion. The rown$Tempra technology uses the latent heat of evaporating water to produce the cooling effect. The water is bound in a gel la yer coating a separate container within the beverage can, and is in close thermal contact with the beverage. The consumer twists the base of the can to open a valve, exposing the water to the desiccant held in a separate, evacuated external chamber This initiates evaporation of the water at room temperature. The unit has been designed to meet a target specification set by ma:or beverage customers cooling D55ml of beverage in a DMMml can by 86.E@ in three minutes. This performance level has been achieved in laboratory tests and working samples are currently undergoing focus group trials with customers.
Thermochromics Kabelling Nive a self-heating or self-cooling container a sensor to tell the consumer it is at the correct temperature and the package becomes Ismart> (such packaging is currently under development. The most common use a thermochromics ink dot to indicate the product is at the correct serving temperature following refrigeration or microwave heating. lastic containers of pouring syrup for pancakes can be purchased in the *&3 that are labelled with a thermochromics ink dot to indicate that the syrup is at the right temperature following microwave heating. &imilar examples can be found on supermarket shelves with beer bottle labels that incorporate thermochromics based designs to inform the consumer when a refrigerated beer is cold enough to drink. &mart ackaging oncepts for harmaceuticals &mart packaging concepts that improve case of use could include Idial-a-dose> smart caps and closures that allow the safe dispensing of exact controlled quantities of product, e.g. pharmaceuticals, cleaning materials, and other potentially haardous materials. 3lready a prescription drug bottle with bottle cap alarm is available - it beeps to alert users when it is time to take the medication, and it displays how many times the bottle has been opened and the intervals between openings. The bottle can be connected via a modem to the healthcare center for the automatic transmission of drug usage and, if nec essary, provide feedback to the patient if not in compliance. 'ventually, programmed skin patches using smart gels that rely on changes in skin properties to trigger drug delivery could replace con ventional pill-taking medication.
!ntelligent Tamper-roof ackaging Onowing whether a package has been tampered with is equally important to consumers. Tamper evidence technologies that cannot easily be replicated, e.g. based on optically variable films or gas sensing dyes, involving irreversible color changes, will become more widespread and costeffective for disposable packaging of commodity items. ieoelectric polymeric materials might
be incorporated into package construction so that the package changes color at a certain stress threshold. !n this way, a Hself-bruisingH closure on a bottle or :ar might indicate that attempts had been made to open it. The Future for ackaging The vision of the future of packaging, according to the recently published Foresight report I/aterials" &haping Aur &ociety>, is one in which the package will increasingly operate as a smart system incorporating both smart and conventional materials, adding value and benefits across the packaging supply chain. For smart materials to be adopted in packaging, they need to be inexpensive relative to the value of the product, reliable, accurate, reproducible in their range of operation, and environmentally benign and food contact safe. 'xample"
Modified Atmospheric Packaging (MAP)
/odified 3tmosphere ackaging (/3 is a technique used for prolonging the shelf-life of fresh or minimally processed foods. !n this preservation technique the air surrounding the food in the package is changed to another composition. This way the initial fresh state of the product may be prolonged. !t is the shelf-life of perishable products like meat, fish, fruits and vegetables that will be prolonged with /3 since it slows the natural deterioration of the product. /3 is used with
various types of products. The mixture of gases in the package depends on the type of product, packaging materials and storage temperature. /eat, fish and cheese are non-respiring products needing very low gas permeability films and so-called high barrier films are used. The initial flushed gas-mixture will be maintained inside the /3 package. onversely, fruits and vegetables are respiring products where the interaction of the packaging material with the product is important and so low barrier or so-called high permeability films are used for these. &o long as the permeability (for A4 and A4 of the packaging film is adapted to the productHs level of respiration, an equilibrium modified atmosphere will be established in the package and the shelflife of the product will increase. The three ma:or commodity types are fruits and vegetables, meat and meat products, and seafood. /any products such as red meat, seafood, minimally processed fruits and vegetables, pasta, cheese, bakery goods, poultry, cooked and cured meats, ready meals and dried foods are packaged under /3. !t has been estimated that 4M-B5C of all fresh produce harvested will not reach the consumers table, due to spoilage and mishandling that occurs during distribution. ackaging Films ;hen selecting packaging films (web substrates for '/3 of fruits and vegetables the main characteristics to consider are gas permeability, water vapor transmission rate, mechanical properties, transparency, type of package and sealing reliability. Traditionally used packaging films like K0' (low-density polyethylene, + (polyvinyl chloride, '+3(ethylene-vinyl acetate and A (oriented polypropylene are not permeable enough for highly respiring products like fresh-cut produce, mushrooms and broccoli. 3s fruits and vegetables are respiring products, there is a need to transmit gases through the film. Films designed with these properties are called permeable films. Ather films, called barrier films, are designed to prevent the exchange of gases and are mainly used with non-respiring products like meat and fish. '/3 films developed to control the humidity level as well as the gas composition in the sealed package are beneficial for the prolonged storage of fresh fruits, vegetables and herbs that are sensitive to moisture.
'xamples"
&*2P'T 73/'" 3K!'0 3O3N!7N
A*)&' A0'" 0P65ED
73/'" &3T!&#;3)3 )3A 3$K 73)3&!//373!0*
/3T)!Q 7*/2')" 50/8BF8544
K3&&" 0/M2
K'T*)')>& 73/'" *37 7AA)#3R7!03 2!7T! 23O3)
&'&&!A7" P*7' 4586
