Fresh chicken fillet is a delicate product, and to maintain good quality and shelf life, it must be well preserved This is where the packaging solution plays a crucial role.

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Wenche Aale Hægermark  

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“We have investigated different types of materials, but at the present, there are no good alternatives to plastic that provide similar protection and shelf life, nor from an environmental perspective. Food waste has much more of a negative impact on the environment than the packaging itself. Therefore, we must ensure that chicken fillets maintain their quality and obtain optimal shelf life”, says Marit Kvalvåg Pettersen, senior scientist at Nofima. She is responsible for the research in the ReducePack project.

Nevertheless, it is important that packaging materials have as low  environmental impact as possible. Therefore, Nofima scientists are now investigating whether they can reduce environmental impact by using either thinner plastic or recyclable plastic, or preferably plastic that is both thinner and recyclable.

Master’s students test the effects of various plastic materials

“There are several different types of plastic. The big difference between plastics that can be recycled and those that can’t is that recyclable plastic may only consist of one single type of plastic material. This is called a monomaterial. Non-recyclable plastic consists of combinations of different types of plastic., The reason for such  combination of different types of plastics   is to obtain desired properties and thus the plastic provides better protection. We like to say that this plastic has better barrier properties”, explains Marit.

In this work, , Marit has received goodcontributions from NMBU master’s students Ellen Medhus and Hanne Marie Hauge when testing the different types of plastic. At Nofima’s Packaging Pilot Plant, they packed fresh chicken fillets in both recyclable and non-recyclable plastic, and using plastic of different thicknesses. The fillets were then stored at 4°C for 24 days.

Master students Ellen Medhus and Hanne Marie Hauge at NMBU have controlled and packed chicken filet in different types of plastic. cc: Nofima

Calculating CO₂ emissions

There are many tests that need to be performed to find out what is the most environmentally friendly packaging system regarding fresh chicken fillets. In addition, it is necessary to calculate the CO₂ emissions in relation to the different types of materials. These calculations have been made by scientist Simon Saxegård at NORSUS.

“Greenhouse gas emissions produced by incineration are significantly higher compared to recycling, and not surprisingly, the thinner the plastic material, the lower the total emissions. The environmental impact produced by today’s plastic packaging is around 35 percent higher compared to packaging that consists of fairly thin recyclable plastic”, says Simon Saxegård.

However, there is a big BUT. It makes matters worse if changing the packaging material causes the quality of the chicken fillets to deteriorate and food waste increases.

Investigating odour, bacterial development and fluid loss

This BUT is the reason why Nofima’s experts are taking a thorough approach when investigating the quality of chicken fillets. Firstly, the initial quality is of importance and thus the bacterial level of the fillets is measured at the time of packaging

In addition to bacterial growth, in these studies the off- odour was evaluate, and, they also investigated how much fluid the fillets have lost i.e, the drip loss that had accumulated at the bottom of the packages.

The experts then repeated the same analyses after 8 days, then after 14, 17, 20 and finally after 24 days.

There were almost no differences in drip loss between the different packaging solutions for chicken fillets.

Several different types of bacteria have been analysed

Ellen Medhus and Hanne Marie Hauge investigated changes in both the total number of bacteria and some selected common spoilage bacteria for fresh chicken fillets. They took a closer look at lactic acid bacteria, the type of bacteria called Brochothrix thermosphacta, and bacteria in the Enterobacteriaceae family (which includes bacteria such as E. coli).

A distinct odour is produced when the number of lactic acid bacteria or Brochothrix bacteria reaches a certain level. However, bacteria in the Enterobacteriaceae family do not produce an odour.

This also occurred in our trials, but neither the odour nor the bacteria levels exceeded acceptable levels. Nor did the number of bacteria from the odourless Enterobacteriaceae family become too high”, Marit concludes.

She then adds: “We got promising results. There are no significant differences between the different packaging solutions, and it seems that fresh chicken fillets is protected  as well in recyclable and more environmentally friendly plastic. In the long term, this can result in substantial environmental savings.

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