*4.1. Materials*

Methanol and acetonitrile (HPLC grade) were purchased from Mallinckrodt Baker (Milan, Italy). Ultrapure water was produced by using a Millipore Milli-Q system (Millipore, Bedford, MA, USA). AflaM1 Test immunoa ffinity columns were from VICAM (A Waters Business, Milford, MA, USA). Paper Filters (Whatman 4) were obtained from Whatman International Ltd. (Maidstone, UK). Standard aflatoxin M1 (acetonitrile solution 10 μg/mL) was purchased from Supelco (Bellefonte, PA, USA).
