Controlled and Modified Atmosphere Packaging - Report Example

MODIFIED ATMOSPHERE PACKAGING Student’s Name Course Tutor Date Introduction Modified Atmosphere Packaging (MAP) is also referred to as reduced oxygen packaging, gas flushing or protective atmosphere packaging. MAP is therefore an optimal blend of gases that mainly include carbon dioxide, pure oxygen, and nitrogen within a permeable or a high barrier. A carefully controlled and keenly adjusted blend of gases is developed to satisfy the specific respiration requirements of any packaged food product. MAP enables fresh produce and unprocessed packaged food commodities to effectively maintain their texture, appearance and nutritional value. The working of Modified Atmosphere Packaging The MAP environment is fundamentally formed as a result of balancing a fine blending of the usual atmospheric gases. As mentioned by Church and Parsons(1995, p 143-152), the blended gas is known to slow down the process of product aging so as to enable reduction in colour loss, bad or unpleasant taste and odour that results from product spoilage, deterioration, and rancidity that are collectively caused by microbes and molds. A well balanced maintains and achieves optimal rate of respiration for the preservation of taste, fresh colour, and nutrient content fresh vegetables and fruits, red meat, prepared foods and others to guarantee extended shelf life. Certain materials such as foils, plastic films and other excellent packaging materials with specific demonstration of gas and water permeability properties are essentially selected for use. Such substrates of high barrier become MAP packages up on formation into bags, trays, or even lid stock and then filled with a fine select mixture of atmospheric gases, notably oxygen, nitrogen and carbon dioxide. The selection of packaging films is carefully carried out to appropriately match the needs and characteristics of the food product to be preserved. Rates of water vapour transmission, film permeability, and characteristics of sealing should be measured and subsequently tested at both points of film selection and at package conversion and product filling. This is important because there are variations in the ability of a film to handle characteristics of MAP performance at every stage. The need of MAP The need for using MAP was necessitated in principle, by the varying customer demands. In the world over, customers strive for high quality products with lots of freshness and attractiveness as well as high food quality food at all times. In order to satisfy such expectations, a food manufacturer or seller is therefore pitted against solving myriad of logistical challenges. Long distance transportation of goods lowers the stability of the products, and in effect the food products packed must be attractive enough to influence demand. Consistency in product quality which is reflected in freshness, taste and others is primarily necessary for building customer loyalty. The original durability and freshness of highly perishable products such as fresh vegetables and fruits, fish, meat, and others hugely depend on the influence of the environment besides the raw materials used. Biochemical reactions and microbiological organisms are the fundamental cause for the food spoilage. The spoilage generally starts after harvesting of vegetables and fruits or slaughter of animals and it is not easy to prevent spoilage as the organisms responsible are ever present in the environment and therefore gains access to the food as fast as possible. The only reactionary mechanism to prevent spoilage is to either decelerate or reduce the activities of the organisms. One of the widely applied measures that have been used for a long time is application of cold. Definitely deep frozen foods can not be assumed to be fresh products for such goods have to be constantly frozen which is an added complication as opposed to MAP. MAP therefore depends on some independent parameters such as: • Food quality and its hygienic handling • The machine used in packaging • The gas mixture • The film or packaging material MAP packaging for fruits and vegetables Fruits and vegetables are basically living organisms and thus constantly respires, are perishable products having active metabolic activities taking place even long after harvesting. The shelf life and quality of vegetables and fruits can be essentially extended by correct modification of the atmosphere that surrounds the products. A modified atmosphere refers to a controlled artificial environment achieved by alteration of the normal air composition so as to provide a desirable atmosphere for extended length of storage and produce quality. Modified atmospheres therefore can be achieved by the careful application of controlled atmosphere packaging or controlled atmosphere storage (CA). According to Rodriguez-Aguilera and Oliveira (2009, p 66-83), MAP makes use of polymeric materials or films that have selective permeability for carbon dioxide, oxygen, and water so as to create a modified atmosphere around the packaged product as a result of the metabolic activities and selective permeability of the material used for packaging. The main application for MAP are horticultural good as increased levels of oxygen and reduced levels of oxygen in the atmosphere that surrounds fresh produce arguably presents numerous desirable effects. Modified atmospheres reduces the rate of respiration, production of ethylene, reduces texture and sensitivity losses, improves the retention of chlorophyll and other vital pigments, delays senescence and ripening and also minimises microbial growth and spoilage of products. Consequently, controlled atmosphere requires optimal control of the concentration of oxygen and carbon dioxide around perishable products and fresh produce. It requires complex operating tools and large buildings of specialised storage. It is more applicable when there is need for long term product storage. The techniques of MAP involve passive or active modification and control of the atmosphere that surrounds a product within a given package with a variety of films. Active modification therefore occurs by gas displacement in the package that is then mechanically replaced by a determined mixture of desirable gases. On a lesser application, passive modification takes place when a product is packaged by a specific film type and then an atmosphere of interest is allowed to naturally develop as a result of the respiration of the product and gas diffusion through the film (Zhang et al. 2003, p 143-148). MAP has gained extensive application in the preservation of highly perishable goods and effective retardation of shelf life deterioration of fresh vegetables and fruits. MAP has been found to extend the shelf life of very many perishable commodities by inhibiting weight loss and respiration, retardation of soluble sugars, and acidity. There is also significant inhibition of delay in fruit ripening and lignifications by MAP application. Modified atmosphere packaging (MAP) is therefore mostly used to prolong the shelf life of many fresh produce such as vegetables and fruits. MAP packaging for ham Wrapping of ham is done to encase the product in an atmosphere that is only composed of a specific desirable gases combination, which enables retailers to essentially control the timing of sales as well as extending the shelf life of the product. Modified atmospheres therefore range from Controlled Atmosphere Packaging (CAP) that constitutes a 100% carbon dioxide. It is important in the maintenance of the original purple color of fresh meat. The other one is Modified Atmosphere Packaging (MAP) that contains about 70% oxygen and subsequently 30% carbon dioxide, which is ideal for the initiation of meat blooming, often explained as meat colour change from purple appearance to bright red. MAP with high concentrations of oxygen is vital for keeping the stability of red pigment within the tissues of the muscle that is estimated to be twice the period of the one exposed to air. Ham kept in high oxygen modified atmosphere packaging has been shown to maintain freshness for a period of about one month at -1.5° C, and about three weeks at a temperature of 0° C. Although pathogens that have the ability of multiplying at cold conditions such as Yersinia enterocolitica and Listeria monocytogenes are of concern in MAP technique of meat treatment. The microbes are incapable of growth at very low temperatures below 0°C and are also significantly inhibited by high carbon dioxide concentrations (Lamberts, Smith and Dodds 1991, p 267-297). MAP packaging for potato chips As demonstrated by Zhang et al. (2003) the optimum gas mixture composition for MAP of products such as potato chips is about 2.5% oxygen and 16% carbon dioxide. It is also estimated that the initial gas proportion for maintaining the quality of Microwaveable fried rice is about 10% oxygen as well as 10% carbon dioxide at about a temperature of 5o C is effective. The quality of fresh potato chips could be also be well maintained for a weak at 4oC in a package atmosphere of about 80% oxygen and 20% nitrogen with little addition of about 1.5% citric acid. MAP preparation of products specifically aims at achieving a state referred to as equilibrium in order to yield equilibrium modified atmosphere (EMA). It involves carbon dioxide and oxygen passing between the outside and inside of the film is such a manner that as oxygen gets used up within the pack it is essentially replaced by oxygen emanating from outside, and at the same time a relatively constant carbon dioxide level is maintained. For a packet of potato chips, for example, a typical equilibrium modified atmosphere might consist of about 15% carbon dioxide, 5% oxygen, and 80% nitrogen. This is enough to extend the product shelf life for as long as long one and a half weeks, whereas when the product is under air it would a wonder if it stays fresh for a period of four days. The gas composition can also have a remarkable effect on freshness due to the effects of reactions of oxidation brought about by enzymes due to flesh damage. In such cases, it is important to have a mixture of nitrogen and carbon dioxide in the packaging with total exclusion of oxygen to prevent browning for quite a number of days. The technique has gained wide use in China to prolong the shelf life of many essential fresh products and fresh vegetables and cut fruits as it has proved to be a more economical alternative to controlled atmosphere in extension of storage life. MAP treatment for microwaveable rice The technique is a very effective method of stabilising freshness in rice but not an indefinite method of preservation. Rice manufacturers as well as distributors are normally made aware of the limitations of MAP. As shown by Hintlian and Hotchkiss (1986, p 70-76), in rice preservation, the process of modification definitely tries to lower the concentration of oxygen from the normal 20.9% levels to about 0% so as to accelerate oxidation reactions and slow down aerobic organism growth. The eliminated oxygen can then be replaced by a filler gas, nitrogen that does not take part in any reaction, or carbon dioxide that either inhibit the growth of microbes or lowers the pack pH. Balancing of gases can be achieved by active techniques, notably compensated vacuum and gas flushing. Carbon dioxide has the tendency to dissolve in the food product’s water, a combination resulting in the formation of carbonic acid. For moist products such as microwaveable rice, it is critical that the concentration of carbon dioxide is not more than 50%, since large quantities of carbonic acid results in the contraction of the package, also referred to as vacuum effect. The general requirements for MAP packaging materials for food products Practically, all materials used in packaging highly perishable products such as meat and vegetables basically from synthetic materials, also referred to as plastics. Most of the packaging materials are therefore available in plastic materials owing to their aesthetic values in product marketing, hence available as foils or plastic films. Packaging materials for perishable product must therefore posses the following characteristics: Light in weight Flexible mechanical strength Odourless Very clean and toxicologically harmless) Recyclable Resistance to cold and hot conditions Provision of good barrier characteristics to gases Resistance to fats and oils Cost friendly Sealing capability Essential gases used in MAP for food products Carbon Dioxide Carbon dioxide inhibits the multiplication and growth most aerobic microbes such as bacteria. It is undoubtedly the most significant gas used in food packaging under modified atmospheres. In general, the higher the concentrations of carbon dioxide gas the longer the shelf life of the perishable products. However, it should be noted that water and fat absorb carbon dioxide gases very easily and in effect excessive concentrations of the gas can lead to failures in quality in regard to taste, humidity loss and vacuum effect or packaging concentration hence it should be carried with a lot of precision and keenness. The durability and acceptability of the product therefore depends on the carbon dioxide reductions. If the gas intended to achieve regulation of growth of the microbes then a concentration of about 20% is necessary. It is a natural gas which is quite a available in small concentrations in the atmosphere (Guevara et al 2003, p 167-176). Oxygen The gas is very important for respiratory activities of all living organisms and is significantly responsible for the decay of perishable products. It is the principal requirement for the growth and multiplication of aerobic microbes. In most cases the gas should not be allowed in MAP but in some rare cases some determined proportion of the gas brings some positive outcomes. It is known to keep the effect of freshness in perishable commodities such as fruits and vegetables and red meat. It necessitates respiration in vegetables or fruits. It is known to inhibit or hinder growth of anaerobic microbes in several types of highly perishable foods such as sliced ham and potato chips. Nitrogen Nitrogen is an inert gas and it is mostly used to expel oxygen component of air out of the material being packaged. It is also used as an essential filling gas that cancels the carbon dioxide absorption effect in the perishable products. The gas, which is a natural air component also minimises the vacuum effect. Advantages of MAP According to Parry (1993, p 1-132), the controlled MAP environment necessitates packaging of food to ensure shelf life extension without essentially requiring the use of stabilisers or chemical preservatives. Food marketers and processors heavily rely on MAP to assure maintenance of flavour and freshness of perishable products that constantly meet the expectation of the consumers in terms of quality of the brand, freshness, consistency, and availability of stock. Extended shelf life MAP enables food manufacturers, food processors, food distributors as well as food retailers to significantly have control over quality, costs and availability of the product. Longer cycles of freshness therefore enable grocers to do away with frequent product removal, rotation, and restocking hence minimising costs related to waste disposal and labour. Product distributors can also extend the distribution boundaries or offer a wider variety of commodity lines to the retailer and finally reaching the consumers for limited frequent requirements of product replacement allows business growth in most of the areas. Food manufacturers as well as processors have the ability of taking advantage of extended cycles of replacement in order to achieve reduction in replacement demands of production. Capacity of manufacturing can be enhanced and profitably utilised when new products are developed and offered to the consumers. Thus in summary, the following are the benefits of the new technology of preservation; Decrease product spoilage Reduces germs growth Perishable products retain their form as well as texture. Retention of nutrients content and taste is high. There is preservation of natural colour. Reduction of the need to use food preserving agents is reduced. The longer the products’ shelf life the more economical the use of machines and staff as goods can be held for an extended period in stock. Disadvantages of MAP Current use and knowledge of MAP are principally empirical thus a development of systematic approach to achieving optimal MAP is very fundamental. Although MAP has got many benefits, adoption of the technique has not fully picked up in nations that entirely depend on machinery to implement it. In addition, the technique has not been fully utilised. This may be due to the fact that there is acute shortage of fast and well priced equipment. The film cost is also another reason that hampers commercial adoption of the technique. The synthetic films used for MAP must have high flexibility and relative ease of usage as well as sufficient strength to withstand normal handling procedures. The use of the technique for fresh produce such fruits and vegetables is limited to quite a number of factors and as such no single plastic film can provide all the properties required for the technique. Others limitations of the technique include; Achieving the required gas mixture requires heavy capital input in terms of machinery Slight expenditure for the installation Product specific trials can be expensive It requires technical know-how Packaging Films According to Li , Zhang andWang (2007, p 343–350), the selection of packaging films for MAP is very critical for EMA of vegetables and cut fruits as the principal characteristics to pay attention to are rate of water vapour transmission, gas permeability, transparency, mechanical properties of the products, and sealing reliability and type of package. In most cases, the packaging films commonly used such as low density polyethylene (LDPE), polyvinyl chloride (PVC), oriented polypropylene (OPP) and ethylene-vinyl acetate (EVA) are not very permeable for products with high rates of respiration like vegetables, potatoes, fresh-ct produce and mushrooms. Since fruits and vegetables are living organisms and are in a constant state of respiration, it s imperative to achieve gas transmission from inside and outside of the synthetic film package. Films that are designed with such properties are referred to as permeable films. Other films can also be designed to act as barriers for prevention of gases exchange. They are mainly popular with packaging of products such as fish and meat. Films are also developed to effectively control the level of humidity and composition of gases in the sealed package for the extended period of storage of fresh produce such as vegetables and fruits and herbs that are highly sensitive to moisture. Such films are generally known as modified humidity (MH) or modified atmosphere (MA) packaging films (Mangaraj, Goswami and Mahajan 2009, p 3). The need for temperature control in MAP for food products Temperature control is very important during the use of MAP technique in product packaging as its incorrect use may lead to toxicity of pack contents. The natural environment where vegetables, fruits, potatoes and rice are grown may be home to pathogens such as enterotoxegenic E. coli, Salmonella species, and viruses. Although such microbes may no inhabit MAP packs if the temperatures are maintained within the range of 3-4o C, they may survive during the storage period and could potentially cause food poisoning.  Prior to carrying out mapping, it is important to carry out some essential treatments to the food products to ensure low counts of microbes and safety of consumers. Some of the hygienic preparation includes sanitation in chlorinated water, dewatering and rinsing. Since there is also very high risk of some anaerobic pathogens thriving well in MAP packs, it is generally recommended that a minimum level of oxygen should be between 2-3% to ensure no creation of hazardous conditions (Day 1996, p 4215-4221). Bibliography Church, I.J. & Parsons, A.L.1995, Modified Atmosphere Packaging Technology: A Review, Journal Science Food Agriculture, 67, 143-152 Day, B.P.F. 1996, A perspective of modified atmosphere packaging of fresh produce In Western Europe, Food Science and Technology Today, 4,215-221 Guevara, J.C., Yahia, E.M., Brito de la Fuente, E. & Biserka, S.P. 2003, Effects of elevated concentrations of CO2 in modified atmosphere packaging on the quality of prickly pear cactus stems (Opuntia spp.). Postharv. Biol. Technol. 29: 167-176. Hintlian, C.B. & Hotchkiss, J.H. 1986. The safety of modified atmosphere packaging: a review. Fd. technology, 40, 70-76. Lamberts, A.D., Smith, J.P. & Dodds, K.L. 1991. Shelf life extension and microbial safety of fresh meat – a review. Fd. Microbiology, 8, 267-297. Li, T., Zhang, M. & Wang, S. 2007, Effects of modified atmosphere packaging with a silicon gum film as a window for gas exchange on Agrocybe chaxingu storage. Postharv. Biol. Technol. 43: 343–350. Mangaraj, S., Goswami, T. K. & Mahajan, P. V. 2009, Applications of plastic films for modified atmosphere packaging of fruits and vegetables: A review. Food Eng. Rev. DOI 10.1007/s12393-009-9007-3. Published online:15 July 2009 . Parry, R. T.1993, Principles and applications of MAP of foods, Blackie Academic & Professional, England, 1-132 Rodriguez-Aguilera, R., & Oliveira, J. C. 2009, Review of design engineering methods and applications of active and modified atmosphere packaging systems. Food Eng. Rev. 1: 66-83. Zhang, M., Xiao, G., Peng , J. & Salokhe, V. M. 2003, Effects of modified atmosphere package on preservation of strawberries. Inst. Agrophysics 17: 143-148. Read More

One of the widely applied measures that have been used for a long time is application of cold. Definitely deep frozen foods can not be assumed to be fresh products for such goods have to be constantly frozen which is an added complication as opposed to MAP. MAP therefore depends on some independent parameters such as: • Food quality and its hygienic handling • The machine used in packaging • The gas mixture • The film or packaging material MAP packaging for fruits and vegetables Fruits and vegetables are basically living organisms and thus constantly respires, are perishable products having active metabolic activities taking place even long after harvesting.

The shelf life and quality of vegetables and fruits can be essentially extended by correct modification of the atmosphere that surrounds the products. A modified atmosphere refers to a controlled artificial environment achieved by alteration of the normal air composition so as to provide a desirable atmosphere for extended length of storage and produce quality. Modified atmospheres therefore can be achieved by the careful application of controlled atmosphere packaging or controlled atmosphere storage (CA).

According to Rodriguez-Aguilera and Oliveira (2009, p 66-83), MAP makes use of polymeric materials or films that have selective permeability for carbon dioxide, oxygen, and water so as to create a modified atmosphere around the packaged product as a result of the metabolic activities and selective permeability of the material used for packaging. The main application for MAP are horticultural good as increased levels of oxygen and reduced levels of oxygen in the atmosphere that surrounds fresh produce arguably presents numerous desirable effects.

Modified atmospheres reduces the rate of respiration, production of ethylene, reduces texture and sensitivity losses, improves the retention of chlorophyll and other vital pigments, delays senescence and ripening and also minimises microbial growth and spoilage of products. Consequently, controlled atmosphere requires optimal control of the concentration of oxygen and carbon dioxide around perishable products and fresh produce. It requires complex operating tools and large buildings of specialised storage.

It is more applicable when there is need for long term product storage. The techniques of MAP involve passive or active modification and control of the atmosphere that surrounds a product within a given package with a variety of films. Active modification therefore occurs by gas displacement in the package that is then mechanically replaced by a determined mixture of desirable gases. On a lesser application, passive modification takes place when a product is packaged by a specific film type and then an atmosphere of interest is allowed to naturally develop as a result of the respiration of the product and gas diffusion through the film (Zhang et al.

2003, p 143-148). MAP has gained extensive application in the preservation of highly perishable goods and effective retardation of shelf life deterioration of fresh vegetables and fruits. MAP has been found to extend the shelf life of very many perishable commodities by inhibiting weight loss and respiration, retardation of soluble sugars, and acidity. There is also significant inhibition of delay in fruit ripening and lignifications by MAP application. Modified atmosphere packaging (MAP) is therefore mostly used to prolong the shelf life of many fresh produce such as vegetables and fruits.

MAP packaging for ham Wrapping of ham is done to encase the product in an atmosphere that is only composed of a specific desirable gases combination, which enables retailers to essentially control the timing of sales as well as extending the shelf life of the product. Modified atmospheres therefore range from Controlled Atmosphere Packaging (CAP) that constitutes a 100% carbon dioxide. It is important in the maintenance of the original purple color of fresh meat.

Read More