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Chemical Engineering Unit Operations in Food Processing

As a Chemical Engineer I have always promoted the role that the Chemical Engineering Unit Operation plays in food manufacturing.

Chemical Engineers in Food Manufacturing - Action Innovation at Work

click image to download the pdf


As well as elaborating on Chemical Engineering’s input to progress in the industry, this article simply charts the changes which lead from what we would now call artisanal local food to multinational worldwide distribution of cheap food.

The question as to which of these two is the better from the energy, global warming, health, taste, sustainability …. viewpoints is something that requires attention as the world gets squeezed and another opportunity for Chemical Engineers.

Tired of “One Third of All Food Produced is Lost or Wasted”

Its true that “One Third of All Food Produced is Lost or Wasted” but it does get a bit boring when we hear it over and over along with a means of reducing it which is simple and obvious. This is made worse by the fact that these means of reducing loss are often very daunting and require actions that you have little effect on.

click the image to visit the website

This CTA briefing paper does a good job of summarizing the various places and ways in which these losses can be addressed. It for example shows that consumers in upper income communities need to take care of their actions and reduce losses – something that's hard for the individual to impact on and where no progress is evident. But we should all keep enthusiastic about it and do whatever we can to reduce waste even if our little effort is not going to be significant on its own.

As a Food Processor, a way of looking at this and keeping up the enthusiasm is to see the other benefits of saving food, which are not always considered. Whatever you do to reduce losses in you plant doesn't only reduce losses of food it

  • Reduces agricultural input usage
  • Increases sustainability of you business
  • Saves you money, when the action required (as is often the case) does not require extra cost
  • Reduces greenhouse gas emissions
  • Reduction in water and energy consumption


Reusing and Recycling Potatoe Waste

The recovery of food from Food Industry waste will become more and more attractive as food prices increase and per capita availability decreases.

In general technology is already available to recover value but the viability limits what is done. This is an interesting approach to improve viability by addressing the logistics of handling waste.

click image to visit the site

Projects like these improve the sustainability of the Food Industry.

THINK-EAT-SAVE Food Waste Enjoying Growing Attention

I have written on Food Waste now and then as it's clearly a part of the food supply system where the world can grow food availability using existing technology.

Now a UNEP/FAO lead campaign, supported by initiatives such as WRAP, has been launched.

click image to visit the site

Think-Eat-Save and the slogan “Reduce Your Foodprint” seem to indicate that it is focussed on the consumer, but the information on the site is not limited to the household. The initiative seems to be focussing on the complete food chain.

There is already a wealth of information here, presented in a very readable way, and there are indications of actions to promote awareness and action.

Think-Eat-Save rests on four pillars

Awareness raising on the impact of, and solutions for food loss and waste.

Collaboration and coordination of world-wide initiatives on food loss and waste reduction.

Policy, strategy and programme development for food loss and waste reduction.

Support to investment programmes and projects..


The Food Waste Opportunity

When the Institute of Mechanical Engineers publishes a report on solving the expected world food shortage by reducing loss, you begin to realise this is a very widely recognized problem or opportunity. I already published a paper on this titled Waste in the food value chain: Issues and opportunities in sub-Saharan Africa in 2011, which also highlighted the wasted inputs required to produce the wasted food.
Institute of Mechanical Engineers publishes a Report on Food Waste

from: IMECHE
(click image for full report online)

Most of the solutions are not to do with mechanization, automation or new devices. Cereals lost to poor storage in the third world environment need better management of existing systems and simple waterproofed structures. Losses in the first world retail system are more strongly linked to the need to change consumer behaviour, diet, obesity, visual standards, kitchen control, expiry dates etc than to research new technologies.

The report has some interesting data that bears repeating

  • Half the food that is grown in the world is lost and not eaten
  • 3 calories of energy are required to produce 1 calorie of food energy in the form of cereals
  • 30 calories of energy are required to produce 1 calorie of food energy in the form of bee
  • 50% of the energy input to wheat is required for fertilizer and pesticides
  • 70% of water use is by agriculture
  • Some thoughts after reading this: the food we do eat uses twice as much inputs than it would seem, the waste is mainly not on the field where it would could at least compost and fertilize but is increasingly in urban areas where it unnecessarily loads the waste disposal system.


    EU Food Waste Briefing

    The ACP-EU has recently held on of its rural development briefing on Food Waste.

    click the image to visit the website

    Around one third of all food is wasted which is already frightening enough but with the new concern on climate change it becomes even worse. The food wasted produces emissions in production and disposal for food which is just not used.

    This document presents links to a number of resources which allow the reader to understand the principles but through references to dig deeper into the issues.

    Are You Starting To Think About Carbon Footprints & Sustainability?

    Its my feeling that you need to be! both from a point of view of “saving the world” and from the point of view of satisfying your customers moral desires. The introduction of the lifecycle concept in this argument is very important because a partial analysis can miss larger hidden differences if all impacts are not determined.

    This article by IUFoST is a good place to start understanding the issues and the practices.


    from: IUFoST
    (click image for full story online)

    The article outlines a range of issues such as Life Cycle Assessment, global warming, eutrophication, acidification, abiotic resource use, pesticide use/ecotoxicity, land use, Water use and Carbon Footprint of food and interaction with other impacts, before focussing on food processing.

    It covers the process based approach, assessment boundaries, mass balance, emissions and co-products and highlight the difficulty of assessing complex foods. The paper gives information and links on the sources of data and provides some data comparing the carbon footprints of food.

    A final section shows how the kind of information given here can be used to support decisions and actions in many areas.

    Waste & Over Eating vs Need & Malnutrition

    The work in the United Kindom on waste in the food system has lead to an intriguing, data rich report which is available on the WRAP website.


    bb10fddbb310ebaa21fa47f9fa5068b0.pdf (page 1 of 86).jpg

    from: WRAP
    (click image for full story online)


    Taking the information of how much food is wasted from this report, with the post on excessively nutritious foods and Michele Obama’s work with the the food industry to reduce the energy content in the food they sell together surely indicates a process that should start to redistribute calories.

    Maybe some more about this in future posts.


    SAB Miller Uses Brewery Waste from Alrode Brewery in South Africa to Reduce Carbon Footprint

    I copy this post from Ecowordly, because I think all food processing industries should be investigating the potential of anaerobic digestion to convert waste into biogas to supplement their energy supply. It makes sense in lots of ways!


    SAB Miller, South African grown, second largest brewer in the world has introduced anaerobic digestion to treat the waste leaving its Alrode Brewery in Gauteng, South Africa. Anaerobic fermentation of organic material produces methane, which is used to reduce the consumption of fossil fuel based energy.



    Copper brewhouse in a Trappist brewery

    Brewery Waste & Biogas

    In the brewery the waste is a collection of unavoidable losses of carbohydrate and protein rich materials, which would otherwise be sold as beer or byproduct and the large quantities of water used to maintain a hygienic operation. (more…)

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