Minerals and Heavy Metals in the Whole Raw Milk of Dairy Cows from Different Management Systems and Countries of Origin: A Meta-Analytical Study

Abstract

The objective of this meta-analytical study was to investigate selected macrominerals, microminerals, and toxic heavy metals in the bovine whole-raw-milk (WRM) samples of published data. An analytical data set was constructed from 72 different studies from 37 countries with two types of production systems: a conventional production system (CPS) and an organic production system (OPS) compared with commercially available or retail-store-available milk (COM). Results of the meta-analytical study showed differences in the concentrations of macrominerals. Concentrations of Ca, Mg, K, and P were greater in the CPS samples, whereas Na was greater in the COM samples ( P < 0.05). Data also demonstrated that concentrations of microminerals like Cu, I, Fe, Mn, Se, and Zn in the organic WRM were lower ( P < 0.05) compared with the milk from CPS. The highest concentration of Ni was reported for COM ( P < 0.05); however, this value was below the minimum-risk level (MRL). Concentrations of heavy metals like As and Ni were greater in CPS milk than those in organic milk ( P < 0.05). In addition, there were greater concentrations of Cd and Pb in the WRM from CPS versus that from the organic farms. Concentration of Al was lowest in the OPS milk versus Al in the CPS which was 6.5-fold greater than in organic milk. The amount of Hg was below the MRL of 0.01 μmol/L for all production systems. A high variability was observed in the published data regarding the country of origin. Raw milk originating from Europe and North America was characterized by concentrations of macro- and microminerals below the MRLs as compared with that from specific countries, which had some minerals above the MRLs. For example, concentrations of Pb were above the MRL in the milk samples from Brazil, Croatia, Egypt, Mexico, Nigeria, Palestine, Romania, Serbia, and Turkey. Moreover, data from this study indicate that organic dairy farms are characterized by lower concentrations of toxic heavy metals in the WRM compared with those from CPS dairy farms.

Effect of the mixture of mulberry leaf powder and KGM flour on promoting calcium absorption and bone mineral density in vivo

“…Table lists the total calcium content and the contents of different forms of calcium in MLP. The data show that the total calcium content in the MLP reached 16 148.5 mg kg −1 (dry base) – much higher than those of food ingredients as calcium supplement in daily life, such as milk (1200 mg kg −1 ), soy products (3670 mg kg −1 ) and cheese (5900 mg kg −1 ) . The calcium, including water soluble one, calcium pectinate and calcium carbonate, can be absorbed readily, accounting for approximately 60% of the total calcium content.…”

Mineral Elements in the Raw Milk of Several Dairy Farms in the Province of Alberta

“…It should be noted that all the data presented in this study with regards to milk minerals in the 26 dairy farms in Alberta are compared with the data we generated and published in a previous meta-analytical study [6]. The data from this study will also be compared with mineral content of the world raw milk originating from world CONV dairy farms and from world COMM or retail stores.…”

“…Heavy metals such as cadmium (Cd), chromium (Cr), lead (Pb), or nickel (Ni) accumulate in plant materials and consequently pass into the milk and milk products. Recently, we reported that concentrations of two heavy metals including Cd in the raw milk from several areas of India, Nigeria, Palestine, and Slovakia, and Pb from several areas of Brazil, Croatia, Egypt, India, Mexico, Nigeria, Palestine, Serbia, and Turkey were above their MRLs (minimum risk levels) [6]. However, to the best of our knowledge, there is no data published with regards to content of milk metals in the raw milk of dairy cows in Canada.…”

“…Indeed, in a recent meta-analytical study, we investigated mineral status of dairy cow raw milk from 37 countries and three types of production systems, including conventional (CONV), organic, and commercial (COMM) or retail store. Data showed that the organic milk has the lowest concentrations of the reported heavy metals versus the conventional and retail store milk [6]. Moreover, several heavy metals were found to be present in concentrations higher than the MRLs for the identified metals (Pb, As, and Hg) in several countries and areas of the world.…”

“…Therefore, the objective of this study was to quantify major macro- and microminerals as well as several heavy metals in the raw milk of Holstein dairy cows from 26 dairy farms in the province of Alberta. The aim is to compare results of this study with data collected and reported in our recently published meta-analytical study related to raw milk metals reported from different countries and with regards to the management system (organic, conventional, or retail store milk world-wide) [6]. The second aim is to provide important information to dairy producers in Alberta, Canada and beyond, as well as to nutritionists, nutrition advisors or consultants, food safety specialists, and different consumer groups with regards to milk metal content.…”