What is food processing?

The term, ‘food processing’ refers to any operation (mechanical, physical or chemical) carried out on food in order to change its properties. It can be a single operation or a combination of different ones. Food processing is carried out in order to make food suitable to be consumed or stored.

Everything we do at home in our own kitchen is a type of processing. For example, cutting, mixing, heating or filling. Even fresh vegetables, like carrots or cucumber from our garden, will be processed because we need to clean, trim, peel and cut them before we are able to enjoy them. Many food processing operations that we conduct at home are the same as those used industrially, just on a smaller scale.

Before food can be processed, the raw materials must be produced. Crops must be harvested, cattle slaughtered, and milk or eggs collected. (This course doesn’t cover this primary stage of the food system, but if you are interested, take a look at ‘Explore how farmers produce food sustainably’). Once we have the raw material, food processing can start – either in your own kitchen or in an industrial factory. Industrial food processing includes simple operations such as cutting, cleaning and packaging, but also mixing, heating, cooling, drying, smoking, fermenting and some highly technical processes that can’t be carried out at home. During this online course you will learn about most of the technologies that are widely applied in industry to process food.

The aim of food processing on an industrial scale is to deliver high quality, safe products that meet the demands of consumers. Three key considerations underpin this aim:

1. The product needs to be safe to consume for the duration of its shelf-life (under appropriate storage conditions). This means that the processing step needs to inactivate microorganisms that are responsible for spoilage, or, alternatively, create an environment where bacterial growth is inhibited. For example, heating inactivates many microorganisms and drying creates an environment where bacterial growth is inhibited as the water activity (the water that’s accessible to bacteria) is too low.

2. The quality of the raw product must be maintained or enhanced during processing. With fresh produce, this means preserving the health-promoting qualities of the raw materials, such as conserving vitamin C during the production of orange juice.

3. Processing must take account of sustainability both in terms of the resources consumed during the operations, and in minimising waste by reducing deterioration at all stages of the supply chain as well during storage.

To ensure the quality and safety of the products that come out of the factory, there are many legal standards a food processing company must comply with and we will look at some of these in Week 4.

Before we move on to look at why we process food in more detail, you might have heard of the term ‘ultra-processed food’ and wonder how it differs from other processed foods. There are many different classification categories of processing techniques, including ‘ultra-processing’, but no agreement yet about which is most suitable. The term was coined by Monteiro in 2010, who developed a food classification system and defined ‘ultra-processing’ as the process of combining unprocessed, or minimally processed, foods with extracted or purified components from whole food (which are often solely for industrial use) to create convenient and shelf-stable ready-to-eat or ready-to-heat products [1,2,3]. These products often contain additives such as stabilizers, emulsifiers, thickeners, colorants, sweeteners and flavours. According to Monteiro’s classification, this category includes many ready-to-eat products, savoury and sweet snacks, soft drinks, etc. Many of the foods categorised as such are associated with a poor-quality diet. However, we should bear in mind what the Swiss doctor and philosopher Paracelsus said: ‘the dose makes the poison’. A balanced diet is important, but food classified as ultra-processed is not going to harm you if consumed occasionally and in moderation.

We won’t use the term ‘ultra-processed foods’ on this course and we won’t be using any processing classifications in our descriptions of the techniques we cover.

Activity

Which of the three key considerations that underpin food processing is most important to you? Safety? Quality/nutrition? Or Sustainability?

Please share your views in the comments section below and explain why. Remember to respect others’ opinions. There are good reasons to support all of these considerations.

References can be found under the ‘Downloads’ heading at the bottom of the final Step in the Week.

To keep track of your progress through the course, don’t forget to mark this Step as ‘complete’ before you move on.