Potassium sodium tartrate

Potassium sodium tartrate, widely known as Rochelle salt, is a mixed potassium and sodium salt of tartaric acid — one of the oldest known synthetic chemicals, prepared since the 17th century. In food it functions as an acidity regulator and emulsifying salt, most commonly used in processed cheese to improve texture and meltability. It imparts no flavour at typical use concentrations and is also used in confectionery and certain beverages.

JECFA's ADI is 30 mg per kilogram body weight per day, evaluated in 1978 under the tartrate group ADI. It is metabolised through the same pathway as other tartrate salts, with partial gut fermentation and renal excretion. No adverse effects have been identified at any realistic dietary intake. Both the potassium and sodium contributions are nutritionally negligible at food additive concentrations.

Potassium sodium tartrate is approved in the EU, US (GRAS), UK, and most global markets. It is a well-established emulsifying salt in processed cheese manufacturing. Given its centuries-long history of use and thoroughly characterised safety profile, it is one of the most trusted acidity regulators available. There are no specific health concerns for healthy adults beyond the modest sodium contribution, which is not meaningful at typical serving sizes.