Lead in milk

Beach JR, Henning SJ. 1988. The distribution of lead in milk and the fate of milk lead in the gastrointestinal tract of suckling rats. Pediatr Res 23 58-62. 

The uncertainty associated with a traceable value must be related to a specified measurand (analyte) and be related to stated references. The following example illustrates the effect the choice of stated reference has on the stated uncertainty for the measurement of lead in milk. The uncertainty of a measurement of lead in milk, measured using a standard method, could be small, if stated relative to that standard method, where the measurand (analyte) is implicitly defined by the standard method. However, the method is likely to contain some additional errors and uncertainties if it were to be related to a primary method traceable to the SI, and these would need to be included in the estimate of uncertainty, if the SI was quoted as the stated reference. The interrelationship between uncertainty and... 

An analyst needs to calibrate an atomic absorption spectrophotometer used for the determination of lead in milk samples. The analyst can purchase a certified reference material (CRM) solution of lead in nitric acid. This CRM is used to prepare a set of calibration standard solutions of known concentration of lead. These calibration standards, along with a suitable blank material (see Section 5.4), are used to calibrate the instrument. 

Crews, H.M., Baxter, M.J., Bigwood, T. et al.. Lead in feed incident—multielement analysis of cattle feed and tissues by ICP-MS and co-operative quality assurance scheme for lead in milk. Food Additives Contam., 9(4) (1992) 365-378. 

TeliSman, J., PongraCid, J., Cretnik, R., and Prpid-Majid, D., Lead in milk and indicatcws of lead absorption in cows from lead contaminated and control areas, in Heavy Metals in the Environment, Vol. 1, Lekkas T.D. (Ed.), CEP Consultants Ltd., Edinburgh, 1985, pp. 417-419. 

The primary focus of these programs has been on the. "tin" can. There are two types of tin cans with which FDA has had concerns the "vent hole" can and the ordinary "sanitary" can. The evaporated milk industry utilizes the "vent hole" can exclusively. In the early 1970 s, an excessive lead content was found in evaporated milk. As a result, FDA initiated a quality assurance program with the evaporated milk industry to ensure compliance with a 0.5 ppm limit on lead in milk. Through cooperative effort, a decline from 0.52 ppm in 1972 to less than 0.10 ppm was achieved. 

Excretion of lead in milk of dairy cows contribiftes very small amounts of lead to die diet. However, individual cows recovered from lead toxicosis should be sampled for milk lead levels prior to entry into the herd. 

The leading states in milk production in decreasing order are Wisconsin, Minnesota, New York, California, and Pennsylvania. These states produce - 45% of the U.S. milk supply. Less than 5% of the total production is used on farms and the remainder is sold for commercial purposes. Whereas milk and cream were formerly shipped in 19-, 30-, or 38-L cans from the farm to the plant, in the 1990s most commercial production, particularly for fluid milk, is moved in bulk from the cows to refrigerated farm tanks to insulated bulk tmck tankers and to the manufacturing plant. The investment in equipment and the cost of hired labor are associated with large, capital-intensive production centers. 

AVP plays a central role in water homeostasis of terrestrial mammals, leading to water conservation by the kidney. OT is primarily involved in milk ejection, parturition and in sexual and maternal behaviour. Both hormones are pqDtides secreted by the neurohypophysis, and both act also as neurotransmitters in the central nervous system (CNS). The major hormonal targets for AVP are the renal tubules and vascular myocytes. The hormonal targets for OT are the myoepithelial cells... 

Iron Rat In utero or milk transfer of lead in pregnant or lactating rats Iron deficiency increases both in utero and milk transfer of lead to sucklings Cerklewski 1980... 

Zinc Rat Lead transfer in utero and in milk during lactation Low-zinc diet of mother increases lead transfer in utero and in maternal milk Cerklewski 1979... 

Gulson et al. (1998) used measured lead isotope ratios (207Pb/206Pb and 206Pb/204Pb) in mothers breast milk and in infants blood to establish that, for the first 60-90 days postpartum, the contribution from breast milk to blood lead in the infants varied from 36% to 80%. Maternal bone and diet appear to be the major sources of lead in breast milk. Mean lead concentration ( standard deviation) in breast milk for participants in the study was 0.73 0.70 pg/kg. 

In a review of data on occupational chemicals that may contaminate breast milk (Byczkowski et al. 1994), it is stated that lead may be excreted in milk in amounts lethal to the infant and that the metal may be mobilized from bone stores to milk during the lactation period. Even when the concentration of lead in mother s milk is low, the absorption of metals into the systemic circulation of infants is generally high when they are on a milk diet. To better understand the sensitivity of the nursing infant to chemicals, epidemiological studies, chemical monitoring, and model development and application are needed. 

Bell RR, Spickett JT. 1981. The influence of milk in the diet on the toxicity of orally ingested lead in rats. Food Cosmet Toxicol 19 429-436. 

Capar SG, Rigsby EJ. 1989. Survey of lead in canned evaporated milk. J Assoc Off Anal Chem 72 416-417. 

Gulson BL, Jameson CW, Mahaffey KR, et al. 1998. Relationships of lead in breast milk to lead in blood, urine, and diet of the infant and mother. Environ Health Perspect 106(10) 667-674. 

Ong CN, Phoon WO, Law HY, et al. 1985. Concentrations of lead in maternal blood, cord blood, and breast milk. Archives of Disease in Childhood 60 756-759. 

Oskarsson A, Jorhem L, Sundberg J, et al. 1992. Lead poisoning in cattle-transfer of lead to milk. Sci Total Environ 111 83-94. 

AOAC Method 979.17 Lead in evaporated milk and fruit juice (1984)... 

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