Foods and packaging can be detrimental to quality and/or safety. Changes in product flavor due to aroma sorption and the transfer of undesirable flavors from packaging to foods are important mechanisms of deterioration when foods are packaged in polymer‐based materials. Careful consideration must be given to those factors affecting such interactions when selecting packaging materials in order to maximize product quality, safety, and shelf‐life while minimizing undesirable changes. Product considerations include sensitivity to flavor and related deteriorations, color changes, vitamin loss, microbial activity, and amount of flavor available. Storage considerations include temperature, time, and processing method. Polymer considerations include type of polymer and processing method, volume, or mass of polymer to product ratio. Methodology to determine the extent of such interactions must be developed. Direct interactions between food and packaging are not necessarily detrimental. The same principles governing undesirable interactions can be used to affect desirable outcomes. Examples include films which directly intercept or absorb oxygen, inhibit microorganisms, remove undesirable flavors by sorption, or indicate safety and product shelf‐life.
Food contact materials are an underestimated source of chemical food contamination. They have the potential to release and subsequent transfer components into the food. The extent to which migration occurs depends on physicochemical properties of the migrant, of the packaging material and the food composition (e.g., fat content). Different additives which are added in large amount are the largest challenge for control of food packaging contaminants. More than 3000 substances of varying origin (packaging, storage, and processing) are considered relevant for food safety control.
Plastic food packing materials –
The additives like plasticizers, antioxidants, UV stabilizers, colors, printing inks, etc. can migrate into the packaged food. Furthermore, the residues of mono and oligomers of the materials as well as additives required for the polymerization may also be migrated into the food.
Timer, Paper, and paper board – Printing inks and chemical used in the pulp and paper production can migrate through paper boards into the foods. chlorophenols formed during the bleaching of wood pulp for paper manufacture can be responsible for taints.
Iron-based metal bodies – Usually these are coated inside the polymers to avoid direct contact with food. Corrosion by high-salt or acidic food items is a major issue. Aluminum cans have to be covered with polymers as well since aluminum is a quite corrosion-prone metal.
Food packaging materials are also a source of heavy metals. It is not always possible to analyze actual food for nature and quantity of migrants from the plastics so simulants or extractants are used as substitute.
How Packaging Materials Affect Food Safety?
- Migration of residual chemicals
- Insufficient barrier properties
- Packaging failure
- Loss of seal integrity
Migration involves the mass transfer from an external source into food by sub microscopic processes impacting food safety and quality. Migration can occur by
– Classified as direct contact migration as it is physicochemical dependent
– Packaging components penetrate and diffuse across packaging material layers due to chemical interactions
– Indirect contact migration where molecules travel through gas phase
– Volatile components can migrate or “jump” from material into foods
– Migration due to set off components during manufacture or storage
Migration of additives from packaging material to food –
There are two types of migration a) Global Migration b) Specific Migration.
- Global Migration – It refers to the total transfer that is the quantity of all substances migrating from the package into the packaged food (Unit: mg/dm2)
- Specific migration – It related to the transfer of one or more identifiable substances that is a constituent of the packaging material (Unit: mg/kg)
Factor Affecting Rate and Extent of Migration in Packaged Food
- Concentration and properties of migrant in the packaging materials
- Concentration and properties of migrant in the printing ink
- Properties of polymer used to produce the food packaging materials.
- Maximum solvent absorption in the polymer
- Storage period
- Storage temperature
- Contact area.
- Fat content in the food
- Adhesives used to seal packaging.
Food contact materials are an underestimated source of chemical food contamination. A major role of food packaging materials is the avoidance of risk related to microbial or chemical contamination of the food, i.e., unwanted events, which may imply serious health risks. Chemical properties of the migrant, of the packaging material, and the food (e.g., fat content); temperature, storage time, and size of the packaging material in the preparation to the food stuff volume (smaller size packaging has a larger surface to volume ratio) decides the rate of migration.
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