Historical clue formulations

• Controversial food preservative, for short — 2018-03-07
• Food preservative abbr. — 2016-10-23
• Food preservative letters — 2015-09-07
• Food preservative, for short — 2013-12-31
• All-natural food no-no — 2003-08-14
• All-natural food no-no — 2000-07-22
• Common preservative — 1999-12-30