Environmental impact of the ice cream industry

Stages in ice cream manufacturing

 

Despite the great variety of ice cream and edible ice products, the manufacturing process for most of these products typically involves the following steps:^[1]

• Preparation of a liquid mixture of ingredients
• Pasteurisation of the mixture to destroy pathogenic bacteria
• Homogenisation to ensure individual fat globules are about 1 µm
• Ageing of the mixture which helps to improve whipping qualities as well as body and texture of ice cream ^[2]
• Dynamic freezing of the mixture to a soft, semi-frozen slurry
• Incorporation of flavouring ingredients into the partially frozen mixture
• Packaging or shaping of the product
• Further freezing (hardening) of the product.

 

Energy consumption and CO₂ emissions

 

A team of UK researchers conducted a comprehensive life cycle assessment of ice cream, using market-leading vanilla and chocolate ice creams as case studies. Based on the annual UK consumption of ice cream of 404 kt, it was estimated that the sector consumes around 17.3 PJ of primary energy per year and emits 1.6 Mt CO₂ eq., therefore accounting for 1.8% of the GHG emissions from the entire food and drink sector in the UK.^[3]

They found that the overall environmental impacts of ice cream were mainly due to the ingredients, while the impacts from the manufacturing process were mostly attributable to energy consumption, particularly from the hardening and storage processes. The calculated impacts were influenced by storage time at the manufacturer and retailer, as well as the type of refrigerant used. For instance, decreasing the storage time at the manufacturer from the baseline of 30 days to 15 days reduced the energy demand by 5%.^[3]

 

Environmental impact of refrigerants used in ice cream manufacturing and retail

 

Ammonia has been used for a long time and is the most common refrigerant used in large-scale ice cream operations.^[4]

HFC R404A is also very common in ice cream manufacturing, despite its high GWP of 4200. The authors of a study on ice cream viscosity described a scraped-surface batch freezer. The freezer consisted of a jacketed cylindrical tank with a capacity of 500 mL. This tank was coupled to a primary cooling system using R404A refrigerant and a secondary cooling bath using ethylene glycol. This system could reach a bath temperature of about −30°C. The cooled ethylene glycol circulated inside the freezer jacket. During the crystallisation process, the energy consumption gradually increased as the temperature of the semi-frozen phase decreased. The authors observed that the energy increase in the power consumed by the stirring motor of the freezer was proportional to the increase in the fraction of crystals formed, and therefore related to the increase in the viscosity of the ice cream which determines its quality.^[5]

 

Given the high GWP of R404A, alternative refrigerants are needed in ice cream manufacturing. For example, a R290/DME (propane/dimethyl ether) mixture was tested in one study. The author found that ice cream formation time was shorter and the COP was higher than that of a R404A system.^[6] In the UK, an ice cream company recently installed an energy-efficient freezing technology using CO₂ as a refrigerant.^[7]

 

At the retail stage, the most common HFCs used in existing food retail and food service operations, according to UNEP, are R404A and R134a (GWP 1360).^[8] Stand-alone commercial systems have mostly switched to R290 (GWP <1).^[8] The authors of the life cycle assessment of the UK ice cream industry compared the impacts of R134a, R152a and ammonia at the retail stage. They found that using R152a or ammonia would decrease ozone depletion potential by up to 95%. R152a would also reduce global warming potential by 1.1%. The authors suggested that reducing storage time along with using refrigerants with low ozone depletion and global warming potentials should help reduce the environmental impacts of the ice cream industry.^[3]

 

 

This document is an excerpt from a more comprehensive thematic file available to IIR members only:

Ice cream manufacturing, environmental impact and market data

 

 

Useful links for further information

 

 

Acknowledgements

 

This summary document was prepared by Monique Baha (IIR head office), revised by Dr. Antonina Tvorogova (member of the C2 commission on “Food science & engineering”), Pr Adisa Azapagic (University of Manchester) and Dr Laurence Stamford (University of Manchester). It was proofread by Nathalie de Grissac and Zoé Martin, under the supervision of Jean-Luc Dupont (Head of the Scientific and Technical Information Department).

 

 

References

[1] Ice Cream (pp. 1–17). Springer US. https://doi.org/10.1007/978-1-4614-6096-1_1

[2] Goff, H. D. (2021). Ageing of Mix. In Ice Cream Technology eBook (University of Guelph). https://books.lib.uoguelph.ca/icecreamtechnologyebook/chapter/ageing-of-mix/

[3] Konstantas, A., Stamford, L., & Azapagic, A. (2019). Environmental impacts of ice cream. Journal of Cleaner Production, 209, 259–272. https://doi.org/10.1016/j.jclepro.2018.10.237

[4] Goff, H. D., & Hartel, R. W. (2013). Chapter 7—Freezing and Refrigeration. In H. D. Goff & R. W. Hartel (Eds.), Ice Cream (pp. 193–248). Springer US. https://doi.org/10.1007/978-1-4614-6096-1_7

[5] De la Cruz Martínez, A., Delgado Portales, R. E., Pérez Martínez, J. D., González Ramírez, J. E., Villalobos Lara, A. D., Borras Enríquez, A. J., & Moscosa Santillán, M. (2020). Estimation of Ice Cream Mixture Viscosity during Batch Crystallization in a Scraped Surface Heat Exchanger. Processes, 8(2), 2. https://doi.org/10.3390/pr8020167

[6] Kim, N.-H. (2016). Application of the Natural Refrigerant Mixture R-290/DME to a Soft Ice Cream Refrigerator. International Journal of Air-Conditioning and Refrigeration, 24(04), 1650027. https://doi.org/10.1142/S2010132516500279

[7] Starfrost Ltd (UK). (2021, August 3). Starfrost Helix spiral freezer delivers energy efficiency benefits at Mackie’s of Scotland. British Frozen Food Federation (BFFF). https://bfff.co.uk/starfrost-helix-spiral-freezer-deliveres-energy-efficiency-benefits-at-mackies-of-scotland/

[8] UNEP. (2021). Refrigeration, Air Conditioning and Heat Pumps TOC (RTOC) Progress Report. In Technology and Economic Assessment Panel (TEAP) 2021. Progress Report (Volume 1). https://ozone.unep.org/node/11983

 

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