Extruded phosphorescence based oxygen sensors for large-scale packaging applications

Abstract

Extruded phosphorescent O2-sensitive composite materials comprising cross-linked polystyrene-divinylbenzene (PS-DVB) microspheres impregnated with Ptbenzoporphyrin dye and dispersed in low-density polyethylene (LDPE) or polylactic acid (PLA) carrier polymer are described. The sensors produced by hot melt extrusion method are specifically tailored to large-scale packaging applications and nondestructive measurement of residual O2 in packaged food products. A panel of LDPE and PLA based sensor materials in the form of extruded pellets and thin film structures were produced and their structural features and O2 sensing characteristics assessed with the view of packaging applications. The extruded LDPE film sensors were also integrated in packaging materials by heat lamination, to produce 'smart' packaging materials which also protect the sensor from direct contact with food. Analytical performance of extruded sensors was demonstrated by incorporating them in modified atmosphere packaged meat and cheese samples and monitoring residual O2 levels in these packs non-destructively with a handheld Optech® reader over product shelf life. The extruded O2 sensors show superiority over the sensors previously used or usable in packaged food products. This technology advances scaled manufacturing of optical O2 sensors, their integration in packaging platforms and cost reduction.

AIEgens: An emerging fluorescent sensing tool to aid food safety and quality control

“…Molecular oxygen (O 2 ) is one of the most important chemical species for life on earth. Determination of O 2 has important implications for bio-medicinal, industrial, and environmental chemistry (Kelly et al, 2020). For food packaging, the shelf-life of prepacked food depends on O 2 level because it can promote the growth of fungi and microorganisms (Yousefi et al, 2019 13d).…”

Functional Polymers and Polymer–Dye Composites for Food Sensing

“…In the past decades, the use of polymer‐dye composites as a design platform of food sensors has attracted great interest, since this methodology is relatively easy to implement and scale‐up. [ 42,45–54 ] In general, this type of sensor could be fabricated through immobilization of dyes into a polymer matrix through either physical blending or covalent chemical bonding. Compared to covalent bonding, the physical blending often encounters the problem of dye leaching from the polymer matrix, which may lead to decreased sensing sensitivity and potential food contamination.…”

3D printed O2indicators

“…However, this feature and, more importantly, the simplicity and scalability of the method by which they are produced makes it likely that they will retail at a much lower price than their current commercial counterparts which, as others have noted, are 'difficult to manufacture'. 17 Other work carried out on the 3D printed O 2 sensitive dots showed that large batches, i.e. arrays, can be easily printed on one sheet of PET and that the reproducibility of such batches, in terms of O 2 sensitivity, within a batch (typically containing 9 indicator dots) and from batch to batch was >98.5%.…”

“…As noted by others, this high cost is because of the complexity of manufacture which is 'slow and difficult to control and standardise'. 17 As a consequence, although commonly used in many different areas, especially for research and product development, O 2 optical indicator technology has not found widespread use in applications, such as in packaging, where they are likely to have significant impact but which would require their low-cost mass manufacture and subsequent large-scale utilisation. Indeed, Kelly et al, commenting on O 2 optical indicators, notes that in order 'to become viable in mass-scale packaging applications, indicator costs need to be reduced by at least ∼2 orders'.…”

“…Indeed, Kelly et al, commenting on O 2 optical indicators, notes that in order 'to become viable in mass-scale packaging applications, indicator costs need to be reduced by at least ∼2 orders'. 17 In recent years, 3D printing has been utilised by many industries, such as aeronautics, industrial tooling, healthcare ( pills and medical devices), construction, robotics, and the automotive industry, for the large scale production of 3D printed parts and products. 18 The advantages 3D printing has over most other methods of manufacture include speed of production of the final item, low initial capital investment cost, greater flexibility in product design and changing product design, less material waste and often a lower per item production cost, since it usually involves single step manufacture and near zero labour costs.…”