The composition and occurrence of aflatoxin M1 (AFM1) were investigated in 60 samples of cow's raw milk samples from Razavi Khorasan Province of Iran. Only percentages of milk samples protein, lactose and total solids in samples collected during summer were slightly lower than the Iranian reference values. Compared with summer samples, higher percentages of milk samples components were observed in the winter. The overall mean AFM1 level was 61 ± 8 ng/L, with 24 samples (40%) showing concentrations above the maximum permitted level established in Iran (50 ng/L). Control measures are urgently needed to avoid aflatoxin in milk samples produced in Razavi Khorasan Province.

The effectiveness of size‐fractionated raw bentonite to reduce the excretion rate of aflatoxin M1 (AFM1) in milk from dairy cows receiving aflatoxin B1 (AFB1) was investigated. The reduction effect of the size‐fractionated clay (particle size: < 5 micrometers) on the carry‐over of the AFB1 ingested by dairy cows into AFM1 in milk (0.43%) was equivalent to the value obtained by a commercially available adsorbent (0.40%). The transferring rate of AFM1 to cows' milk can be reduced effectively by using more economic, raw mineral clays with appropriate particle sizes as prepared in this study.

In this trial, 60 samples of raw cow's milk collected during summer and winter in five collective centers from Khorasan Razavi Province of Iran were analyzed for penicillin residues, somatic cell counts (SCC), mesophilic counts (TMC) and adulteration materials. The mean penicillin level (0.57 ± 0.20 μg/L) was much lower than the maximum permitted level (MPL) recommended by the Codex Alimentarius Commission (4 μg/L). However, the mean SCC and TMC (Log 5.71 ± 0.08 cells/mL and Log 6.18 ± 0.11 colony forming units (CFU)/mL, respectively) exceeded their respective MPLs adopted in Iran for grade C milk (Log 5.69 cells/mL and Log 6.0 CFU/mL, respectively), with higher counts (P < 0.05) in the summer. High frequencies of samples containing salt (53-60%), detergents (16-20%) and formalin (7-10%) were observed in milk samples, stressing the need for stringent control measures to improve the quality of milk delivered in the evaluated collection centers.