Mexican candy - a seemingly harmless indulgence - can contain a poison that is especially dangerous to children. Story by JENIFER B. McKIM, KEITH SHARON and WILLIAM HEISEL Photos by ANA VENEGAS The Orange County Register SWEET INNOCENCE: For birthday girl Elva Alexandra Cardona, 2, right, the Pelon Pelo Rico she enjoys with cousin Giselle Yanez, left, is just a sugary treat. But the candy, which has tested high for lead 11 times, and others like it have increasingly been linked to poisoning of California children. SUMMARY Situation: The state finds lead in candy one out of four times it...