Effects of feed iodine concentrations and milk processing on iodine concentrations of cows’ milk and dairy products, and potential impact on iodine intake in Swiss adults

Abstract

The contribution of milk and dairy products to daily iodine intake is high but variable in many industrialised countries. Factors that affect iodine concentrations in milk and dairy products are only poorly understood. Our aim was to: (1) assess the effect of feed iodine concentration on milk iodine by supplementing five groups of five cows each with one of five dosages from 0–2 mg iodine/kg DM; (2) quantify iodine losses during manufacturing of cheese and yogurt from milk with varying iodine concentrations and assess the effect of cellar-ripening; and (3) systematically measure iodine partitioning during heat treatment and skimming of milk. Milk iodine reached a near-steady state after 3 weeks of feeding. Median milk iodine (17–302 μg/l for 0–2 mg iodine/kg DM) increased linearly with feed iodine (R2 0·96; P < 0·001). At curd separation, 75–84 % of iodine was lost in whey. Dairy iodine increased linearly with milk iodine (semi-hard cheese: R2 0·95; P < 0·001; fresh cheese and yogurt: R2 1·00; P < 0·001), and cellar-ripening had no effect. Heat treatment had no significant effect, whereas skimming increased (P < 0·001) milk iodine concentration by only 1–2 μg/l. Mean daily intake of dairy products by Swiss adults is estimated at 213 g, which would contribute 13–52 % of the adults’ RDA for iodine if cow feed is supplemented with 0·5–2 mg iodine/kg DM. Thus, modulation of feed iodine levels can help achieve desirable iodine concentrations in milk and dairy products, and thereby optimise their contribution to human iodine nutrition to avoid both deficiency and excess.

Óleo essencial de Lippia origanoides (Verbenaceae) na higienização de tetos de vacas leiteiras

“…Os resultados aqui obtidos são importantes ao considerar que o efeito foi semelhante ao de produtos convencionais, considerando que esses apresentam alguns inconvenientes na sua utilização, como indução de resistência aos biocidas (Fitzpatrick,et al, 2016 ), e a presença de resíduos no leite, sendo veiculados para bezerros ( Van der Reijden, et al, 2018),e para humanos (Ahvanooei, et al, 2021;Ahvanooei, et al, 2020;Coneyworth, et al, 2020;Van der Reijden, et al, 2019), conforme pesquisas que relatam presença de iodo.…”

Changing Dietary Habits in Veneto Region over Two Decades: Still a Long Road to Go to Reach an Iodine-Sufficient Status

“…Some papers have investigated iodine from a cheese production perspective. It is well known that a large proportion of the iodine in milk is lost in the whey during the cheese-making process, but the loss of moisture during the cheese curdling and ripening processes raises the iodine concentration in cheese from 1.7 [27] to 2.6 times that of milk [28]. Haldimann et al [29] studied the diffuse migration of iodine in four different types of hard cheese after immersion in brine supplemented with iodized salt in the form of potassium iodine.…”

Large Variability of Iodine Content in Retail Cow’s Milk in the U.S.

“…As illustrated in Figure 4, iodine supplementation has a large influence on the iodine content of milk. For example, increased iodine intake of dairy cattle resulted in increased milk iodine concentration [54,55]. In addition to different levels and forms of supplemental iodine, feed and plant materials vary in iodine content due to passive iodine uptake from water, soil, and air, or by contamination, and can affect iodine levels in milk [21,22].…”

“…Other causes of iodine variability in milk have been hypothesized. For example, iodine loss during pasteurization has been observed in some studies [22,70,71] but not in others [52,55]. Also, ultra-high-temperature (UHT) processed milk had 27% lower iodine than conventional retail milk and organic milk had 44% lower iodine than conventional milk in a retail study across the United Kingdom (Figure 4) [72].…”