By Harold McGee
Hydrogenated vegetable shortenings and chlorinated flour are very useful, but have drawbacks that lead some bakers to avoid them. Hydrogenated shortening does not have the flavor that butter does, and has the more serious disadvantage of containing high levels of trans fatty acids (10–35% compared to butter’s 3–4%;). Chlorinated flour has a distinctive taste that some bakers dislike (others find that it enhances cake aroma). And the chlorine ends up in fat-like flour molecules that accumulate in animal bodies. There’s no evidence that this accumulation is harmful, but the European Union and the United Kingdom consider the safety of chlorinated flour unproven, and forbid its use. The U.S. FDA and the World Health Organization consider chlorinated flour a safe ingredient for human consumption.