Processed food (Q&A)
20 March 2017
In a recent consumer study, we investigated the understanding of processed food among the UK participants. This Q&A summarises the topics explored in the study.
1. What is food processing?
Food processing is any method used to turn fresh foods into food products.1 This can involve one or a combination of the following: washing, chopping, pasteurising, freezing, fermenting, packaging and many more.2 Food processing also includes adding components to food, for example to extend shelf life, or adding vitamins and minerals to improve the nutritional quality of the food (fortification).3,4
2. What are the methods of food processing?
Food processing includes traditional (heat treatment, fermentation, pickling, smoking, drying, curing) and modern methods (canning, freezing, pasteurisation, ultra-heat treatment, high pressure processing, or modified atmosphere packaging). Some of the common methods are described below:
The food is heated to a high temperature and then stored in an air-tight container.
The breakdown of sugars using bacteria, yeasts or other microorganisms under anaerobic conditions. Fermentation is notably used in the production of alcoholic beverages such as wine, beer, and cider, in the preservation of foods such as sauerkraut, dry sausages, and yoghurt, but also for raising dough in bread production.
Food temperatures are reduced to below -18°C to decrease the activity of harmful bacteria. The process can be used to preserve the majority of foods including fruits, vegetables, meat, fish, and ready meals.
Modified atmosphere packaging
Air inside a package is substituted by a protective gas mix, often including oxygen, carbon dioxide and nitrogen, to extend the shelf life of fresh food products - usually of fruits, vegetables, meat and meat products, and seafood.
Food is heated to at least 72°C for at least 15 seconds to kill most of the microorganisms, and then cooled rapidly to 5°C. Pasteurisation is used widely in preservation of canned food, dairy products, juices and alcoholic beverages.
A process of heat and chemical treatment of food to help preserve it by exposing it to smoke from burning material such as wood. Smoked foods usually include types of meat, sausages, fish or cheese. Smoked meat and meat products should not be consumed in excess of the current guidelines. For more information, read our recent science brief.
Food additives play an important role in preserving the freshness, safety, taste, appearance and texture of processed foods. Food additives are added for particular purposes, whether to ensure food safety, or to maintain food quality during the shelf-life of a product. For example, antioxidants prevent fats and oils from becoming rancid, while preservatives prevent or reduce the growth of microbes (e.g. mould on bread). Emulsifiers are used for instance in improving the texture of mayonnaise, or stopping salad dressings from separating into oil and water.
3. What are the reasons and consequences of food processing?
Makes food edible
Grain crops, for example wheat and corn, are not edible in their natural state. Processing techniques, such as milling and grinding, turn them into flour, after which they can be made into breads, cereals, pasta and other edible grain-based products.
Safety, shelf life, and preservation
Processing improves food safety by removing harmful microorganisms. The main methods are pasteurisation, air-tight packaging, and the use of preservatives.
Food processing can affect the nutritional quality of foods in both ways: it can enhance it, for instance by adding components that were not present, like vitamin D, or by lowering fat, sodium or sugar. It can also cause some vitamins and minerals to be lost, for example through excessive heating or freezing.
Processing and packaging technologies help to answer modern day time constraints by providing a range of convenient foods: ready meals, bagged salads, sliced and canned fruits and vegetables that take little time to prepare and can be consumed “on the go”.
Food processing can decrease the cost of foods. For example, frozen vegetables have a similar nutritional value as fresh ones, but at a lower price, as they have already been prepared, do not contain inedible parts, can be bought in bulk, and can last longer. This way, processing increases the shelf life of food, and decreases the amount of waste, reducing thereby the overall costs of food production.
4. How does processed food fit into a healthy diet?
Most foods consumed these days are processed at least to some degree. They allow us to enjoy a varied diet that goes together with a busy modern lifestyle. Many people don’t have the option to grow their own, or may have limited time to cook complicated meals from scratch. Processed food reduces the amount of time needed, while a range of foods of different processing levels may fit into a healthy diet. Minimally processed foods such as frozen or canned fruits and vegetables provide valuable sources of nutrition, with greater convenience and lower price. Highly processed foods, such as healthier types of breakfast cereals, can still be a part of a healthy diet.
Some processed foods do contain additional salt, sugar or fat. Canned savoury foods and cured meats, for example, are often high in salt. Checking the levels of salt, sugar and fat and comparing with the recommended intakes helps us choose the healthier option, and eat appropriate portions. This encourages us, for example, to pick the tinned fruit in juice rather than in syrup, or chose canned fish in water rather than in oil. It also helps to be mindful and eat in moderation food products such as biscuits, chocolate bars, burgers, pizzas and similar.
For more information please see:
- EUFIC (2016). Understanding perceptions of processed food among UK consumers. A qualitative consumer study by EUFIC. EUFIC Forum n° 7.
- EUFIC Review (2010). The greatest thing since sliced bread? A review of the benefits of processed foods.
- Monteiro C, et al. (2010). A new classification of foods based on the extent and purpose of their processing. Cad Saude Publica 26(11), pp. 2039-2049.
- Floros J, et al. (2010). Feeding the world today and tomorrow: the importance of food science and technology. Comprehensive Reviews in Food Science and Food Safety 9(5), pp. 572–599.
- Dwyer J, et al. (2012). Is ‘Processed’ a four-letter word? The role of processed foods in achieving dietary guidelines and nutrients recommendations. American Society for Nutrition 3, pp. 536-548.
- Weaver C, et al. (2014). Processed food: contributions to nutrition. The American Journal of Clinical Nutrition (AJCN) 99(6), pp. 1525-1542.