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Agroscope, Federal Food Safety and Veterinary Office (FSVO)

Use of Iodised Salt in Cheesemaking Improves Iodine Sufficiency

Sections of the Swiss population are deficient in iodine. Agroscope and the Federal Food Safety and Veterinary Office (FSVO) examined how the use of iodised salt affects the iodine content of cheese.

Iodised table salt was launched in 1922 at the behest of the Swiss Confederation in order to protect the population from the serious consequences of iodine deficiency. Despite the steady increase in iodine concentrations in iodised salt, sections of the population – particularly pregnant and breastfeeding women and their infants – are still deficient in this important trace element. Iodised salt, which is used in food processing, covers approx. 54% of the Swiss population’s iodine requirement. This fact makes it clear that the use of iodised salt is essential for meeting the iodine requirements of the population in Switzerland.

Milk and dairy products are important sources of iodine

Milk and dairy products are intrinsically important sources of iodine. A recent study shows that individuals consuming organically and conventionally grown dairy products achieve a daily intake of around 21 and 33 μg iodine (14% and 22% of the recommended daily intake, respectively).

Using iodised salt in cheesemaking could improve iodine supply

A highly water-soluble element, iodine is part of the milk serum and is separated from the cheese curd together with the whey during cheesemaking. The use of iodised salt in the brine bath and subsequent ripening of the cheese is a worthwhile measure from the viewpoint of iodine supply. Because of the high consumption of over 21kg cheese per person and year and the important role of this popular food category in sodium intake, cheese manufacturers could make a major contribution to meeting the Swiss population’s requirements for the balanced and sufficient supply of iodine.

Joint Agroscope and FSVO study on iodide diffusion in cheese

The effectiveness of such a measure depends largely on the extent to which the potassium iodide (KI) added to the table salt (NaCl) diffuses into the edible part of the cheese during brining and the subsequent ripening. In order to clarify unresolved questions on iodide diffusion in cheese, various cheeses were made in Agroscope’s experimental cheese dairy with iodised and non-iodised table salt and analysed at regular intervals during the course of ripening.

Study results reveal high potential

The experimental cheeses produced with non-iodised salt had an iodine content of 30 µg/kg (Tilsiter), 35 µg/kg (Gruyère) and 57 µg/kg (Camembert). When iodised salt was used, the iodine concentration in the edible part of the cheese increased to 474 µg/kg in the Tilsiter, 409 µg/kg in the Gruyère and 445 µg/kg in the Camembert. If all cheeses were produced with iodised rather than non-iodised salt, the contribution to iodine supply could be increased from an average of 1.8 µg per day (non-iodised salt) to just under 18 µg per day (iodised salt). The percentage of the recommended daily intake of iodine met by cheese consumption would thus rise from 1.2% to 12%.

Conclusions

  • The study results show that brining and smearing the cheese with iodised salt increases the iodine content in the edible part of the cheese by a factor of around 10.
  • Since the consumption of cheese is common in nearly all sections of the population, the blanket use of iodised table salt in the manufacture of Swiss cheese could make an important contribution to an adequate iodine intake in the Swiss population.
  • The use of iodised salt in cheesemaking appears to be a more appropriate approach than a further increase in the iodine concentration in table salt. Consequently, the FSVO and Agroscope recommend the use of iodised salt to Switzerland’s cheese industry.

Scientific article

Use of Iodised Salt in Cheesemaking Improves Iodine Sufficiency

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