The research looked at the life cycle environmental impacts of a ‘typical’ British 360 g roast dinner consisting of chicken, vegetables (peas, potatoes and carrots) and tomato sauce – comparing ready-made meals manufactured industrially to versions prepared at home from scratch.
The study, published in the Journal of Cleaner Production, looked at the ready meals from production line to home and found that environmental impacts such as eutrophication, photochemical smog and ozone layer depletion were up to three times lower with the home-made meal.
Of the ready meal versions, the UK researchers said the worst option for most impacts included was the frozen ready meal with frozen ingredients that was heated in an electric oven. The best ready meal was the frozen meal prepared from fresh ingredients and heated by consumers at home in a microwave, they wrote.
They said this was primarily due to the manufacturing processes involved as well as refrigeration and waste rates - with fewer storage stages with home preparation. They added the research aimed to provide recommendations to producers, retailers and consumers alike.
Read, steady, eutrophication
The researchers said the “main hotspots” for both types of meal were the ingredients, waste, as well as the home cooking method.
They said the type of refrigerant used in the supply chain influenced things like global warming and ozone layer depletion, while packaging played a part in things like global warming, fossil fuel depletion and human toxicity.
Meanwhile they wrote: “Using organic instead of conventional ingredients leads to higher impacts. Sourcing chicken and tomatoes from Brazil and Spain, respectively, reduces environmental impacts of the meals compared to sourcing them from the UK, despite the long-distance transport.”
Comparing the home-made meal with the British ingredients to the ready-made meal prepared with the Brazilian chicken, the ready-made meal was a better option for five eco impacts. The researchers speculated that this was due to "agricultural impacts related to the British and Brazilian chickens".
From field to fork
The results indicate that the environmental impacts of preparing the meal at home using conventionally-cultivated ingredients were lower than for the equivalent ready-made meal for ten out of the 11 impacts considered.
However, the 'marine aquatic ecotoxicity potential' was higher by 7% for the ready meal because of the higher electricity consumption in the preparation of the home meal comparatively.
The researchers concluded that this results demonstrated that producers, retailers and consumers could all play a role in reducing the environmental impacts of food by making more informed choices.
"In particular, producers should consider sourcing their ingredients taking into account a growing knowledge and information available on life cycle environmental impacts of different ingredients. Furthermore, both producers and retailers should work on reducing the amount of packaging and waste in the supply chain. Minimising refrigeration time and using low-impact refrigerants would also lead to environmental improvements," they wrote.
Source: Journal of Cleaner Production
Vol. 73, Iss. June 2014, pp. 294–309, doi: 10.1016/j.jclepro.2014.01.008
“Life cycle environmental impacts of convenience food: Comparison of ready and home-made meals”
Authors: X. C. Schmidt Rivera, N. Espinoza Orias, A. Azapagic