Calcium citrate is the calcium salt of citric acid. Triethyl citrate is an ester of citric acid. Acids can be added in manufacturing such as acetic, malic, tartaric, and citric. Khus syrup is made by adding khus essence to sugar, water and citric acid syrup. Citric and oxalic acids are used as rust removal. Succinic acid is notable as a component in the citric acid cycle. Potassium ferrocyanide is used in the production of wine and citric acid. Although a weak acid, exposure to pure citric acid can cause adverse effects. These agents include citric and phosphoric acids, which are nonaggressive. The malate anion is an intermediate in the citric acid cycle. Berkeley's formula contained pyrogallol, sulfite, and citric acid. This mechanism replenishes the intermediates of the citric acid cycle. The other product of transamidation is a keto acid that enters the citric acid cycle. Citric acid has 247 kcal per 100 g. Diacetyl can be produced by the LAB through metabolism of sugar or of citric acid.