Food safety: why stainless steel is a vital ingredient

Food safety starts with rigorous hygiene, and nickel-containing stainless steels are the superior, reliable standard at every link of the food chain.

Food supply and food safety are very much current issues across the globe. According to the World Health Organisation, one in ten people fall ill each year from eating contaminated food and 420 thousand people die each year as a result, with young children at particularly high risk.

Regulators are also taking food safety seriously. The Food Safety Modernization Act in the US; China’s 2015/6 revisions to the Food Safety Law, tightening of regulations on food contact materials in India, and in Europe EDQM’s Technical Guide on Metals and Alloys Used in Food Contact Materials and Articles are just a few examples.

  • In the EU, Food Safety regulatory context is offered by the following three regulations:

    1. Framework Regulation EC 1935/2004 (materials)
      • This decrees that materials of food equipment construction should not alter taste, food quality or colour of foodstuffs
      • Nor should these materials cause diseases or adversely affect human health
      • This is of importance to material producers
    2. Machinery directive EC 2006/42 (hygienic design and execution)
      • This stipulates how food equipment should be designed and fabricated in order to keep food safe during processing
      • This is of importance to equipment manufacturers
    3. Food Hygiene Regulation EC 852/2004
      • Focuses on keeping food safe and maintaining hygienic conditions during preparation from farm to fork,
      • It is directed towards food business operators but is intended to hold materials and equipment manufacturers accountable too


    Overall, the aim of these regulations is that material producers, equipment manufacturers and food business operators jointly assume responsibility of keeping food safe-to-eat from farm to fork.

Investments in food safety that are based on sound science and science-based regulation can assist in meeting the SDG targets.

Investments in food safety that are based on sound science and science-based regulation can assist in meeting the SDG targets and help tackle food contamination, while ensuring adequate returns to the food industry.

One such investment is in using nickel-containing stainless steel equipment. Many food related industries – food processing, catering or domestic cooking, irrespective of their commercial size— benefit from the hygienic properties of stainless steel while keeping food safe for consumers all along the value chain.

Nickel-containing stainless steels do not alter the food’s taste or colour, do not contaminate the food and critically provide exceptional performance for maintaining food safety by being easily and effectively cleaned and sterilized.

Designed for hygiene

When designing or choosing equipment for the food industry, ‘hygiene’ covers many aspects. Fabrication materials must be able to resist the build-up of process soils as well as be easily disinfected and cleaned between production runs. They must not corrode or impart their constituents to the food in quantities deleterious to human health. Nickel-containing stainless steel offers all this and much more. Their formability, machinability and weldability into complex shapes and components allows their fabrication to fine tolerances to be both practicable and economically feasible.

Milking the benefits

One practical example where nickel containing stainless steel is ubiquitous is the milking parlour. Here it serves a market where profits are narrow and problems such as mastitis and milk contamination can be catastrophic for the dairy farmer. Hygiene is paramount, involving careful daily washing down and sterilisation of pipework, milking equipment and tanks. Stainless steel with attributes such as corrosion resistance against excrement and cleanability performs well in this tough environment and helps the objectives of hygiene and disinfection to be accomplished.

Stainless steel is also essential in keeping the milk fresh. Milk is monitored for bacteria counts and if it is not very strictly controlled, can be rejected. When milk arrives from the cows’ udder at 35 °C, it is very quickly chilled down to 4–6 °C to prevent bacterial growth and is kept in stainless steel tanks usually equipped with stirrers or agitators to await collection. Heat exchangers are an important part of the dairy industry for cooling and heating and are used to extract the heat from the raw milk. In some cases, the heat is further used, for example in pre-heating wash water or space heating. Stainless steels are also used for the truck mounted milk tanker vessels which transport the milk from the parlour tanks to factories for further processing.

Courtesy Fullwood Ltd.
Courtesy Fullwood Ltd.

Whether the milk is pasteurised for drinking, dried as milk powder or goes on to make cheese, yoghurt, butter or ice cream, stainless steel equipment is necessary to meet very strict hygiene standards.

Grades used are primarily Type 304L (UNS S30403) and Type 316L (S31603) stainless steels although duplex alloys are now being used under more exacting conditions.

Why are stainless steels so suitable for rigorous hygienic applications?

Cleanability is the key to hygiene. The smooth, bright surfaces of stainless steel are eminently cleanable and can remain so over time. It withstands wear, impact and fluctuations in temperatures while inhibiting dirt and scale accumulation.

And the naturally forming self-healing passive layer provides the corrosion protection rather than an applied coating, which may be damaged and degenerate. The ability to easily wash and sanitise stainless steel allows for bacteria to be removed effectively and simply. Tests have demonstrated that stainless steel has a low bacterial retention capacity, making it a very attractive material for the food industry. Stainless steel enables impeccable cleanability even after repeated use. Strict standards of hygiene are therefore possible at every stage. And the corrosion resistance of stainless steel means it is inert and does not alter the taste or smell of food or drink products, resisting the lactic acids formed by fermenting milk or acidic foods like tomatoes.

Italy’s secret ingredient

The culinary traditions of Italy provide a prime example of the functionality of stainless steel. By virtue of its hygienic properties, corrosion-resistant characteristics and attractive finish, nickel-containing stainless steel has played a notable role in the Italian food industry which relies on this effective material. For example, stainless steel is widely used for the storage of cocoa paste, cocoa butter, and chocolate. Manufacturing facilities are equipped with stainless steel tanks of varying volumes and weights all using Type 304 (UNS S30400), which is specifically designed to food industry standards. Stainless steel complies with the specifications of the 1973 Italian Ministerial Decree, Hygienic Rules concerning packaging, containers, tools, and equipment coming into contact with food or substances for personal use. This specification provides a list of stainless steel grades that may be used for the food industry.

Italy’s gastronomic reputation combined with its world-famous design edge extends to their cookware. With its pristine finish, durability and resistance to dents and scratches, stainless steel is an attractive choice. By combining functionality, hygiene and design along with flavour preservation, an important component in cookware, stainless steel fulfils stringent specifications. The expertise, know-how, and inventiveness of Italian designers married with the beauty of nickel-containing stainless steel, has allowed them to produce high quality and beautiful cookware.

With its pristine finish, durability and resistance to dents and scratches, stainless steel is an attractive choice.

A stainless steel for every food application

Nickel-containing stainless steel lends itself to a whole host of applications in the food industry. There is an austenitic stainless steel for almost every food application, from milk and beer, where Type 304 is the standard; fish and meat products which may require a higher grade such as Type 316L (S31603); right through to the super-austenitic steels developed to cope with extremely aggressive conditions of, for example, soy sauce production. Its robust corrosion resistance and ease of cleaning make stainless steel both durable and hygienic, two very valuable properties in food service preparation.

Food safety starts with rigorous hygiene, and nickel-containing stainless steels are the superior, reliable standard at every link of the food chain. Today, more than a quarter of all nickel produced goes into stainless steel products related to the food and beverage sector, where it is a vital ingredient in the food supply chain, from farm to fork. Literally.