Calcium montmorillonite clay for the reduction of aflatoxin residues in milk and dairy products

Authors: MAKI, CODY - Texas A&M University; ALLEN, SARAH - Mississippi State University; WANG, MEICHEN - Texas A&M University; WARD, STEPHANIE - Mississippi State University; RUDE, BRIAN - Mississippi State University; HART, BAILEY - Mississippi State University; Harvey, Roger; PHILLIPS, TIMOTHY - Texas A&M University

Submitted to: Journal of Dairy and Veterinary Sciences
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 4/14/2017
Publication Date: 4/28/2017
Publication URL: https://handle.nal.usda.gov/10113/5801843
Citation: Maki, C.R., Allen, S., Wang, M., Ward, S.H., Rude, B.J., Bailey, H.R., Harvey, R.B., Phillips, T.D. 2017. Calcium montmorillonite clay for the reduction of aflatoxin residues in milk and dairy products. Journal of Dairy and Veterinary Sciences. 2(3):1-8.

Interpretive Summary: Aflatoxin (AF) is a toxin produced by fungi that can cause disease and cancer in animals and humans. AF residues are readily transferred into cows’ milk, and AF residues in milk are stringently regulated, prompting the destruction of milk that is above acceptable levels. This costs the dairy industry millions of dollars annually. Twenty-five years ago, researchers at ARS and Texas A&M University, College Station, TX, discovered a compound, NovaSil, that reduced passage of AF into the milk; however, it was not adopted by the dairy industry because of the unknown potential side effects on cows, milk production, and milk quality. The present study showed that cows fed AF and NovaSil had a 13-22% reduction of AF in milk and milk products; yet, there were no differences in dry matter intake, milk yield, milk protein, lactose, vitamin A, or riboflavin due to NovaSil. This is important because it will allow the dairy industry to utilize NovaSil without affecting milk production, but it also assures that the nutrition, wholesomeness, and safety of milk is preserved. Finally, millions of dollars will be realized from the additional sale of milk that otherwise would have been disposed of due to AF contamination.

Technical Abstract: In this study, dairy cows were treated with calcium montmorillonite clay (NovaSil Plus (NSP); BASF Corp., Ludwigshaven, Germany) in a replicated 5x5 Latin square design. The primary objectives were to determine if milk composition was altered following ingestion of NSP, and to investigate the ability of NSP to reduce aflatoxin (AF) transfer to milk with the inclusion of low doses in the diet (concentrations equal to 0.125 and 0.25% w/w). The experiment was conducted at the Bearden Dairy Research Center at Mississippi State University. Cows were housed in a free-stall barn with sand bedding and were fed and milked twice daily. The experiment consisted of 5 10-d periods, where cows were randomly assigned to 1 of 5 dietary treatments (n=3 for each treatment): A. absolute control (CON), basal total mix ration (TMR) with no AF or NSP; B. AF Control (AFC), basal TMR plus 50 ppb AF; C. NSP Control (NSPC), basal TMR plus 0.5% estimated dry matter intake (DMI) NSP; D. low-dose clay with AF (NSP-0.125%), basal TMR plus 0.125% estimated DMI NSP and 50 ppb AF; E. Or high-dose clay with AF (NSP-0.25%), basal TMR plus 0.25% estimated DMI NSP and 50 ppb AF. All additions to the basal TMR were top dressed and mixed into the top of feed offered. Dry matter intake and nutrient intake did not differ among dietary treatments (P>0.05). Milk yield and feed efficiency (FE) were similar throughout all treatments, and no treatment effects were observed for fat yield, lactose, protein yield, solids, or somatic cell count (SCC). Furthermore, vitamin A and riboflavin concentration in milk were similar across all treatments and averaged, 0.30±0.03 and 1.54±0.13µg/mL, respectively. A dose dependent reduction (P<0.01) in concentration of aflatoxin M1 (AFM1) in milk with the inclusion of NSP was shown. Feeding the AFC diet resulted in 0.75±0.05µg AFM1/L; this value was reduced by 13.3% (0.65±0.05µg/L) with the inclusion of NSP at 0.125% of DMI and by 22.7% (0.58±0.05µg/L) when NSP was fed at 0.25% of DMI. Specifically, transfer rate was reduced from 1.66% with the AF diet to 1.43% and 1.28±0.16% with the inclusion of NSP at 0.125% and 0.25% of DMI. Due to reduced transfer rate, total excretion of AFM1 was also reduced (P<0.01) in a dose dependent manner. This study was part of a multistate dairy project. When compared to other studies in this project, NSP resulted in a linear decrease in AFM1 ranging from 13% (at the smallest dose of clay) to 71% (at the greatest dose of clay). At all doses, DMI, milk yield, milk composition, minerals, vitamin A, and riboflavin concentrations were unaffected by the dietary treatments. The inclusion of NSP in contaminated dairy feeds may help mitigate AF problems without affecting milk production or composition. The results of this study will aid in determining the appropriate dosage of NSP needed to decrease AFM1 below allowable concentrations.