Non-migratory bioactive polymers(NMBP)in food packaging 79 5.3.4 Technology availability The commercial availability of technology required to produce NMBP could limit applications. Technologies for functionalising the surface of polymer films are readily available, but newer technologies, which provide controlled surface functionalisation, are still in development; this is especially true with respect to their application in high throughput continuous processes, as required for production of packaging materials. Surface functionalisation is discussed in more detail in section 5.5. Beyond basic surface functionalisation, further modification of film surfaces is not typically practised commercially. Production of most NMBP will require further processing, probably involving wet chemical treatments for immobilisation of active agents, adaptation of existing technologies will be required to implement these treatments. If NMBP becomes widespread, the technology will become more readily available and this will cease to be a limitation 5.3.5 Cost The final limitation of NMBP is the likely increase in cost. NMBP will require further steps and additional materials in film manufacturing/converting processes, increasing production costs. Intensive modifications, such as the attachment of proteins, will incur significant cost increases due to the additional processing steps required, the chemicals used in processing, and from the cost of the agent itself. The peptides, proteins and enzymes involved can be quite expensive, although increased demand will undoubtedly result in cost reductions of these components in the long term. Additionally, the need to recover research and development expenses and new equipment requirements will also increase the film cost. Over time, new equipment will become cheaper and more readil available, increased material availability should lead to lower material costs and the overall cost of the films will decrease. This is typical of the cycle involved in introducing new technologies 5.4 Inherently bioactive synthetic polymers: types and applications As previously mentioned, there are two main types of NMBP- inherently bioactive polymers and polymers with covalently immobilised bioactive agents For inherently bioactive polymers, the structural polymer itself is bioactive. For example, polymers containing free amines have been shown to be antimicrobial (Shearer et al., 2000). Included in this definition are structural polymers with modified backbones. These polymers differ from those with immobilised bioactive compounds in that no previously synthesised bioactive compound is attached to the polymer chain. Several materials have been found to have nherent bioactivity(Oh et al, 2001; Ozdemir and Sadikoglu, 1998; Shearer ef al., 2000; Vigo, 1999, Vigo and Leonas, 1999)and new ones are currently being5.3.4 Technology availability The commercial availability of technology required to produce NMBP could limit applications. Technologies for functionalising the surface of polymer films are readily available, but newer technologies, which provide controlled surface functionalisation, are still in development; this is especially true with respect to their application in high throughput continuous processes, as required for production of packaging materials. Surface functionalisation is discussed in more detail in section 5.5. Beyond basic surface functionalisation, further modification of film surfaces is not typically practised commercially. Production of most NMBP will require further processing, probably involving wet chemical treatments for immobilisation of active agents; adaptation of existing technologies will be required to implement these treatments. If NMBP becomes widespread, the technology will become more readily available and this will cease to be a limitation. 5.3.5 Cost The final limitation of NMBP is the likely increase in cost. NMBP will require further steps and additional materials in film manufacturing/converting processes, increasing production costs. Intensive modifications, such as the attachment of proteins, will incur significant cost increases due to the additional processing steps required, the chemicals used in processing, and from the cost of the agent itself. The peptides, proteins and enzymes involved can be quite expensive, although increased demand will undoubtedly result in cost reductions of these components in the long term. Additionally, the need to recover research and development expenses and new equipment requirements will also increase the film cost. Over time, new equipment will become cheaper and more readily available, increased material availability should lead to lower material costs and the overall cost of the films will decrease. This is typical of the cycle involved in introducing new technologies. 5.4 Inherently bioactive synthetic polymers: types and applications As previously mentioned, there are two main types of NMBP – inherently bioactive polymers and polymers with covalently immobilised bioactive agents. For inherently bioactive polymers, the structural polymer itself is bioactive. For example, polymers containing free amines have been shown to be antimicrobial (Shearer et al., 2000). Included in this definition are structural polymers with modified backbones. These polymers differ from those with immobilised bioactive compounds in that no previously synthesised bioactive compound is attached to the polymer chain. Several materials have been found to have inherent bioactivity (Oh et al., 2001; Ozdemir and Sadikoglu, 1998; Shearer et al., 2000; Vigo, 1999; Vigo and Leonas, 1999) and new ones are currently being Non-migratory bioactive polymers (NMBP) in food packaging 79