What is the “rinse aid” in the dishwasher used for, how it works and the effects on health

Use one dishwasheran appliance owned by almost 40% of Italian families, is a common gesture for many Italians, an increasingly appreciated help in household chores and which also allows us to reduce water consumption daily. The dishwasher, in addition to water and soap, uses an additional ingredient, unknown to those who wash their dishes by hand, to try to improve the results of the washing cycle: this is the rinse aidan additive designed for help drying and improve the shine of dishes in the wash cycle, favoring the evaporation of water e reducing limestone residues. We don’t have to worry about residues on the dishes, but if accidentally ingested or in contact with mucous membranes, such as the eyes, can cause serious damage and burns.

Limescale residues and fogging: the downsides of the dishwasher

While the dishwasher is an excellent help, there can also be some inconveniences. THE’evaporation of waterafter the wash cycle, can be a problem, and it also depends heavily by materials or shapes of dishes to wash: plastic containers or jars tend to dry more slowly and often they retain water residues. The causes are the high level of residual humidity and the poor air circulation in the appliance: for this reason, crockery can often show signs of damage after drying evident traces of limestone or a general fogging of surfaces.

How to use it and what it contains rinse aid

To eliminate or reduce this “disadvantage“ compared to manual or outdoor drying, the rinse aid, a solution that at the end of the wash promote evaporation and dripping of water residues. The ingredients of the rinse aid can be various: a 1982 patent by Procter & Gamble proposes the use of nonionic surfactants, that is, they do not have an electric charge. These surfactants lower the surface tension of water ensuring that it evaporates more evenly, without leaving stains.

To these is usually added a chelating agent such ascitric acidwhich breaks down limestone residues “sequestering” the calcium ions present in the water. Finally, a variable percentage of is added to the mixture zinc, tin and other metal ionsdesigned to protect glasses and other glassy materials fromfogging caused by alkaline soaps more aggressive.

Is dishwasher rinse aid bad for your health?

Although appliance manufacturers declare that not using rinse aid, unlike other products, such as dishwasher salt, it does not damage the dishwasher, but theThe use of rinse aid is widespread in restaurant and canteen kitchenswhere using a “dirty” plate or glass, even just with limescale, would be unacceptable. For this reason, one wonders what effect it has on our health.

In 2022, a study by the Swiss Institute of Allergy and Asthma Research (SIAF) highlighted the effects of rinse aid residues on epithelial cells of the intestine, finding traces of toxic effects at concentrations above 1:40,000 (volume ratio between rinse aid product and water) mainly due to nonionic surfactants (ethoxylated).

There is no need to be too alarmed, however: the conclusions of the article (which has passed peer-review) are not in question, but its practical applicability to everyday life is not immediate. First of all, the concentrations tested are decidedly higher than those of washing residues of home dishwashers, which have very long wash cycles and thorough rinsing: concentrations above 1:40,000 are in fact found in the use of industrial dishwashers, designed to obtain more “intense” and short-term washes with rapid drying.

An additional factor to consider is that the rinse aid residue, before it can interact with intestinal epithelial cells, it must survive the entire digestive processinitiated by saliva and continued by gastric juices in the stomach, and then passes through the protective layer of intestinal mucus. The process is highly unlikely second Thomas Wallachhead of the school of pediatric gastroenterology “SUNY Downstate” in Brooklyn and interviewed about it by the NY Times.

However, the brilliant municipalities remain dangerous if ingested directlyor even in case of contact with skin or eyes: in the UK in the period 2008-2019 the national poison control center has recorded dozens of cases of eye irritations and some cases skin rashes or allergic reactions, while as many as 956 operations were recorded for accidental ingestion of the product, with serious consequences on the gastrointestinal tract and in the most serious cases suppression of the central nervous system. All excellent reasons to handle these products with caution, keeping them out of the reach of children.