Use of customers’ own reusable cups for ‘coffee to go’: considering hygiene standards and materials

Reusable cups brought from home should, if possible, be made of smooth, easy-to-clean material and should be empty and clean. This means that consumers should regularly clean reusable cups with hot water and washing-up liquid or in the dishwasher, provided they are suitable for this according to the manufacturer’s instructions, and then dry them thoroughly or leave them to dry completely.

Before shop staff fill a reusable cup, the customer should remove any lid themselves so that the staff do not come into contact with it.

When using reusable cups on a self-service basis, for example at drink vending machines, petrol stations or in canteens and cafeterias, the following should also be observed:

Personal reusable cups should not touch the dispensing nozzle from which the drink flows, in order to prevent the transmission of any germs that may be present. If necessary, refrain from filling the cup if the automatic dispensing machine appears to be unhygienic or is dirty.

With hot drinks, the risk of infection generally is quite low, as most bacteria are killed by heat. Provided standard hygiene practices are followed and the cups are handled correctly, there is no significant additional health risk associated with having private reusable cups filled with hot drinks.

In principle, with used reusable cups, there is a risk that any germs present in them may enter the drink when hot drinks are poured into them. If germs then enter the human body whilst drinking, they can cause infectious diseases. Reusable cups with visible dirt on them should therefore not be refilled before having been cleaned first.

Reusable cups made from materials with a smooth, easy-to-clean surface, such as porcelain, stainless steel, rigid and temperature-stable plastics or glass, are suitable. They must be manufactured in accordance with the applicable legal provisions so that no substances posing a health risk are transferred to food during their intended or foreseeable use. The materials should be dishwasher-safe and heat-resistant, and ideally also resistant to disinfectants and corrosion. Reusable cups should only be used for as long as their surface remains smooth, free from hairline cracks and visible signs of wear.

A few years ago, there was a trend towards reusable cups that were advertised with claims such as ‘made from natural materials’. However, these were primarily made of plastic, such as melamine-formaldehyde resin (MFR). Such plastics merely had ‘natural’ materials, such as bamboo fibres, added as fillers. MFR are polymers and consist of the basic components melamine and formaldehyde. These materials are used in the manufacture of reusable ‘coffee to go’ cups and other tableware and kitchen utensils because they are hard, easy to clean and shatter-resistant. When reusable cups made from MFR are used at room temperature, there are no health concerns. However, if MFR containers are exposed to high heat or filled with hot liquids, melamine and formaldehyde can be released from the material and migrate into food, posing health risks. Articles made from MFR should therefore not be used in the microwave either. In the organism, melamine can damage the bladder and kidneys. Both substances may be carcinogenic. Studies by the monitoring authorities of the German federal states and by the BfRshort forGerman Federal Institute for Risk Assessment have also shown that products labelled as ‘bamboo products’ release, on average, significantly more melamine and formaldehyde than products made from ‘conventional’ MFR.

Fillers such as rice husks or bamboo fibres are not authorised for use in plastic items intended for food contact. Consequently, so-called ‘bamboo products’ have now largely disappeared from the market.

The BfRshort forGerman Federal Institute for Risk Assessment recommends following manufacturers’ instructions printed on reusable cups. This includes, for example, the fact that they are not suitable to be cleaned in a dishwasher or to be used in microwave ovens.

The BfRshort forGerman Federal Institute for Risk Assessment also recommends that articles made of melamine-formaldehyde resin (MFR) should not be used in contact with hot, acidic liquids such as coffee, tea or mulled wine.

With hot drinks, the risk of infection generally is quite low, as most bacteria are killed by heat. Provided standard hygiene practices are followed and the cups are handled correctly, there is no significant additional health risk associated with having reusable cups brought from home filled with hot drinks.