BY THE NUMBERS   In Food, Culture Matters Spending power of ethnic consumers hard to ignore By De J. Lozada Founder, Soul Popped Gourmet Popcorn and The National Association of Black Food Manufacturers I recently walked into a major grocery retail chain in my area and asked where I could find their black hair care products. The store worker was visibly bewildered and went off to find someone who could help. Three employees later,