The intro's actually them tackling the cheese aisle. And then they choose a mozzarella:
" Mr. Moss and Mr. Pollan considered the mozzarella choices, skipping the pre-shredded kind in favor of a cheese that advertised itself as a product of Amish country and that cost the same as the more generic ball beside it.
'Real milk, no hormones, no antibiotics,' Mr. Pollan said, reading aloud from the label. 'I love the term ‘real milk.’ I wonder if we can get fake milk anywhere here.'
So went the shopping trip: everything that went into the cart was subject to scrutiny. "