Plastics used in food technology

Plastics used in food technology

In many areas of industry, technical plastics play a vital role in improving the efficiency and competitive standing of customer applications. Lightweight, versatile plastics have a proven track record stretching back over many decades in the processing and packaging of foods. Their success is based on a combination of material benefits which are brought to bear even at raised temperature levels. These include primarily good mechanical properties and high resistance to chemicals.

There are widely varied application possibilities for technical plastics in plant and machinery for meat, fish and poultry processing, in the manufacture of dairy produce, baked goods and confectionery production.
They are frequently used in this type of application as gears, bearing bushes or in the form of other machine components. Plastics can also come into direct contact with foodstuffs, for example in filling, mixing and portioning systems. Stringent
demands are placed on these plastics, particularly in the case of plant components which come into direct contact with food. The main objective of EU and US regulations is to exclude any damaging effects due to the migration of substances.
There is product-specific conformity certificates with FDA approval for raw material, regulation (EC) No. 1935/2004, (EU) No. 10/2011 (migration tested on semi-finished products) as well as (EC) No. 2023/2006 and seamless traceability.

Food industry

Namely:

Dairy technology
Meat, fish and poultry processing
Bakery technology
Food conveying
Food packaging
Beverage industry

Materials usually used in food Industry:

(POM-C) Good chemical resistance. High resilience.
(POM-H) High mechanical strength. Good chemical resistance. Good machinability.
(PA6) High degree of toughness. Resistance to oils, greases and fuels. Good abrasion resistance.
(PA6+MOS) Low friction coefficient. Good abrasion behaviour. Easy machining capability. For applications without food contact.
(PET) Very light. Very abrasion resistant. Easily machined.
(PEEK) Long-term service temperatures of up to 250 °C. Brief exposures of up to 300 °C. Excellent mechanical properties.
(PC) Easy to polish. Good machinability. Good welding and bonding properties

You are eating an ready-made fruit salad or digging into a plastic container your favorite ice cream. You don’t even think there could be a piece of plastic or metal or just small particles of these materials in there-broken or worn off from the machinery and tools used to get your favorite foods to your grocers’ shelves. But many of the food processing machines and tools used to provide food products have plastic parts in them or are made of plastics. For example, foods like melons, peaches, carrots, strawberries or apples can pick up plastic particulates from plastic tote bins or containers that are damaged or worn. Such foods as olives in a vat can mix with tiny particles from a plastic shovel or scraper as they wear So how can food processers know if there are plastics, or other foreign bodies in the foods they sell?

In two modes:

The principle of detecting plastics in foodstuffs is currently based on visual inspection (blue coloration). However, it is only possible to detect foreign bodies in food if the fragment is positioned close to the surface. In any other event, optical detection is not possible. In this case, any possible defect in a component is only noticed when it is far too late to prevent the destruction of large quantities of food if contamination has taken place.
Optically detectable plastics
(POM-C blue) – (PA blue) – (PEEK blue)
Function: The blue colour of the plastic clearly stands out from the colour of processed foods.
Benefits: Optical detection is economical and continues to prove successful in a wide range of applications.
Some thermoplastics and thermosets, can be made metal detectable using additives at an affordable price. These additives make the material magnetically susceptible enough so that it is conductive and unwanted particulates can be detected with standard metal detectors or x-ray machines. When detecting ID materials by means of a metal detector, the fragment may be located below the surface of the food and still be picked up as a foreign body. This new development permits rapid detection and so minimizes potential damage.
Inductively detectable plastics (ID)
(POM-C grey special ID) – (POM-C blue special ID) – (PA6 blue special ID) – (PEEK blue special ID)
Function: These plastics come complete with an additive to permit detection with the aid of a metal detector.
Benefits: Broken fragments can be quickly traced as part of the standardized process control system. The costly process of destroying whole batches and even image-tainting recall campaigns can be avoided.

Migration tests

In contact with food, reciprocal action between the plastic component and food can result in the migration of substances.
To eliminate the risk of a health hazard as far as possible, the admissible migration of substances and procedures for testing are set out in Regulation (EU) No 10/2011.

EU regulations

In Europe, consumer goods made of plastic which come into contact with food are subject in the main to the following legal regulations:

Regulation (EC) No 1935/2004 as an outline regulation.
Regulation (EC) No 2023/2006 on good manufacturing practice (GMP) for materials and objects intended to come into contact with food.
Regulation (EU) No 10/2011 on materials and objects made of plastic intended to come into contact with food.
Regulation (EU) No 10/2011, also known as PIM (Plastics Implementation Measure), is used as replacement for (EC) No 2002/72, which has now been declared invalid, and the associated regulations. The transitional requirements and exceptions fixed in the current regulation cover the period up to 2016, depending on content.
Regulation (EC) No 2002/72 and the new Regulation (EU) No 10/2011 contain a positive list of monomers and additives which may be used in the manufacture of materials and objects made of plastic.

BfR

In addition to (EG) No 2002/72 and (EU) No10/2011 applicable across Europe, the Federal Institute for Risk Assessment (BfR) issues socalled plastics recommendations on the suitability of different materials for contact with food.

Dyes

Dyes are not listed in the union list and are subject to separate national consideration (e.g. in accordance with BfR stipulations).

US regulations

In the USA, the regulations of the Food and Drug Administration (FDA) and the NSF 51 and 3 A SSI are applicable.

FDA

According to FDA stipulations (in accordance with CFR Title 21 – Food and Drugs) various materials suitable for food contact are recorded on the basis of a positive list.

Part 177 contains the list of standard polymers which are suitable for single or multiple contact with foods.
In part 178, the relevant additives, production aids and dyes are listed.

The positive lists contain information regarding the requirements imposed on physical and chemical composition and also on approved application conditions.

According to the FDA, certificates are issued for stock shapes intended for repeated contact with foods. A suitability statement is provided here with confirmation of the material listing. The end user is also required to provide the FDA with verification of compliance with the migration values and suitability for the finished component.

NSF

NSF International (National Sanitation Foundation) is a not-for-profit organization whose function is to provide certification in the field of health and safety. These standards encompass a very wide range of applications, from water quality through food safety to pharmaceuticals.
The NSF maintains lists of products and manufacturers which comply with their requirements.
To be listed, the material has to be tested. The producing location is also audited.

The NSF/ANSI standard 51 “Food Equipment Materials“ is a generally recognized standard which requires a check of the formulation on the basis of FDA regulations, laboratory testing and an audit of the manufacturing location.
This certification must be extended on a yearly basis.

3-A Dairy

3-A was founded by three dairy-related associations in order to define requirements for the dairy industry in the form of sanitary standards and practices for equipment and systems used in the dairy industry.
The 20-25 3-A Sanitary Standard refers to multiple-use plastic materials in dairies.
The standard describes the cleanability of a material. In addition, it defines that the material may not lose its functional characteristics or surface quality even under tough environmental conditions following regular treatment with bactericides. This area is not covered by the FDA regulations. Although the 20-25 3-A Sanitary Standard is not legally binding, it is generally acknowledged.

Drinking water regulations

Drinking water does not fall within the scope of food manufacturing guidelines, but is monitored in accordance with special regulations which are not internationally standardized at present.
Drinking water is used not only for consumption but frequently used in the preparation of food, either as a manufacturing component or in cleaning processes.

Germany

Plastics in contact with drinking water (KTW)

Testing in accordance with DVGW (German Technical and Scientific Association for Gas and Water) regulations and the 2001 Drinking Water Ordinance 2001 using a microbial growth test in accordance with work sheet W 270.
Migration values in accordance with DIN EN 12873-1: 2004 and -2: 2005 in accordance with the updated guidelines of the German Environmental Protection Agency (dated 08/10/2008).

UK

Testing in accordance with WRAS (Water Regulations Advisory Scheme), certifications from WRc-NSF (Cooperation Water Research Council and NSF). Certificate validity five years.

USA

Testing in accordance with NSF 61 (National Sanitation Foundation) with approvals specific to the manufacturer, specific production locations, material types and temperature specifications.

Other country-specific tests

The country-specific test specifications are not transferrable and must be individually tested in each case. However, their statements are similar in respect to the suitability of specific application conditions for drinking water. These are comparable according to KTW, WRAS and NSF 61 and are classified into three categories:

Cold water (e.g. up to 23 °C)
Warm water (e.g. up to 60 °C)
Hot water (e.g. up to 85 °C)

Specifically Beverage industry

Along with mineral water, a whole series of different types of beverage are manufactured industrially and filled in vessels such as bottles, cans or barrels.
After consumption, the majority of empty bottles are returned for reuse. Technical plastics such as POM-C are available in a range of colours and are ideally suited for use as bottle holders and grippers. After sorting, the bottles are cleaned inside and out. Cleaning plants offer a range of application possibilities for plastics: From mechanical parts at the infeed and outfeed to the bottle slide. These can be manufactured from plastics such as PA+MOS, in order to prevent unnecessary scratches on the glass.

When selecting materials for the production of cleaning plant components, the application conditions have to be taken into account (hot water, high water pressure and use of chemicals). PEEK natural and the modified types comply with the stringent demands involved. In the actual filling plants, plastics are used due to their low specific weight and their good sliding properties. Whether quick-change devices, worm conveyors or slide rails, the lightweight materials help save energy and reduce maintenance costs due to low wear. Cast nylon PA6+MOS with its molybdenum disulphide filler combines good damping properties and high strength. In addition, this material offers improved surface hardness and good slide friction properties even in dry running operations. Plastic components are even used for the final process stages. Typical components
include star conveyors in labelling and packaging machines.