|dc.description.abstract||Preserving meat quality is paramount during meat processing. Contamination is reduced by preventing contact between faecal matter and the carcass. Rectal plugs are used for this purpose during slaughtering, and the animal’s intestines can be removed and entered directly into the rendering process. Polypropylene plugs contaminate rendered products, while Novatein® plugs (the Port Jackson) will break down during the rendering process.
A life cycle assessment (LCA) was used to determine and compare the environmental impacts of plugs made from either polypropylene or Novatein®. Two scenarios were considered, in which the production of the plugs could be contracted out, or manufactured in-house. On an environmental basis, the difference was negligible. Resin production accounted for 73% of the total non-renewable primary energy (NRPE) use and global warming potential (GWP), with the balance shared between plug production, use, and disposal.
Injection moulding and packaging each contributed 31% to GWP, as well as 25.8% and 40% of the NRPE use respectively during plug production and disposal, dominating impacts during plug production. In contrast, operations with the lowest impacts were conditioning and transport, collectively contributing to less than 4% of the entire LCA impacts.
The life cycle impacts were particularly sensitive to packaging, the allocation method used for farming impacts on bloodmeal production, and the ratio of the electricity grid mix. By eliminating cardboard boxes reduced GWP and NRPE use by 6.1% and 6.9%. Allocating impacts from farming to bloodmeal production could increase the GWP by up to 193%, and NRPE by 14%. Allocation is not under the control of the manufacturer, and is a limitation of the assumptions made in this study. By using coal-based electricity, the GWP can increase by 66%, and NRPE by 20%. Impacts from electricity use could change noticeably if the plugs were manufactured overseas.
The net present value (NPV) of capturing 10% of the market, and selling the plugs at $0.15 NZD, at a 35% discount rate was $143,629 when contracting out plug production. Under all costing assumptions, contracting out provided a higher NPV than manufacturing in-house. This is primarily due to the large capital costs when producing in-house.
The critical factor that will cause manufacturing in-house to be more financially viable is the capital cost. The difference between the NPV of the two scenarios is $240,442, and the estimated total cost of buying, shipping, and installing the injection moulder is $355,153. If this can be reduced to $114,711, the two scenarios become equal. Because manufacturing in-house has a higher ongoing cash inflow per year, this scenario will also benefit more from scaling up volume above the 10% market share threshold.
When comparing the Port Jackson with the polypropylene plug, the Novatein® plug has a higher GWP (0.0166 kg CO₂eq per plug) than the PP plug (0.0126 kg CO₂eq per plug), however, it requires less NRPE (0.302 MJ per plug and 0.430 MJ per plug respectively), and if contracted out, can be sold competitively at a matching market value of $0.15 or $0.16 per plug. The price may be lowered even further to $0.12, and still have a positive NPV. These factors are slightly in favour of producing Novatein plugs, but the Port Jackson’s advantage over PP is the fact that it not only breaks down during rendering, but it is also non-toxic, so simply becomes part of part of meat and bone meal.||