On Thursday, the Food and Drug Administration announced that it intends to ban artificial trans fatty acids from the nation's food supply because the substances increase the risk of heart disease. According to the Institute of Medicine, "there is no safe level of consumption of artificial trans fat." But how will we be sure that our food doesn't contain any of the stuff whatsoever? We called up the AOCS, which used to be called the American Oil Chemists Society and now just goes by "Your Global Oil and Fats Connection" and also maintains a blog. Chief executive Patrick Donnelly was in China at a soaps and detergents association conference, but he referred us to Richard Cantrill, the organization's chief science officer and technical director. A lightly edited transcript of our interview follows.

Cut it out. (Sarah Voisin/The Washington Post)

Lydia DePillis: So, you're probably getting a lot of calls from people wondering what's going to happen when trans fats disappear. 

Richard Cantrill: Yes, we are. We spent many years setting up the methods of analysis for trans fats, working with the different industries. So it's been an interesting 24 hours.

LD: I imagine your members have seen this coming for some time. What have they been doing to prepare? 

RC: So, as a professional organization, we're interested in methods of analysis. So we're not affected by the withdrawal of trans fats, but we'll be very much involved in their measurement in the future. The industry came to us in 2005 and said they wanted to sort out the methods of analysis and improve them, and we've spent much of the last eight years sorting them out. And then a couple of weeks ago we published the last of the collaborative study data to validate the methods we've been proposing, so this is actually quite timely.

LD: So, what does that mean? You now know exactly how to determine whether something has trans fats in it? 

RC: Right. We finished a study on 24 different food samples from the food pyramid that you may normally use to discern whether the method of analysis works or not.

LD: Is it even possible to eliminate all trans fats from our diets? 

RC: Well, there's obviously some forms of natural trans fats, so we won't be eliminating those. There are some trans fats that appear as byproducts in oil processing, so we probably won't be eliminating those, either.

LD: Can you tell me anything more about how your members are figuring out how to replace trans fats?

RC: I'm under the impression that they've been reducing trans fats since 1999, when the FDA first thought about regulating. So there has been a lot of reworking done,  a lot of reformulation. Some of our members have written books about it. But we don't know all the activities that have been going on, obviously, or what they've been reformulating with, because those are trade secrets. There are some things they don't tell us.

LD: So how do your methods for measurement get implemented?  

RC: So we hope that members will use it to make sure their incoming materials are low in trans fats and their products are equally low in trans fats.

LD: Did we not know how to measure them before?  

RC: When we first started there was a lot of discussion about how accurate they were, how low can they measure it. So we worked with the oils and fats industry, the food industry and the members of the scientific staff of the FDA to see how good the methods were.

LD: When you get rid of trans fats, do you necessarily change the character of the food? 

RC: I think that has been the problem for the formulators, that trans fats give fat certain crystalline structures, a source of what's called "mouth feel," whether there's a melting sensation.

LD: What's the next harmful fat or oil that we should be concerned about? 

RC: I'll probably have to do it when someone tells me what it is. The whole issue of food contaminants is, unfortunately, reactive. We're not proactive about what a problem is until someone decides it's a problem.

LD: And what prompted the jump to examine trans fats for you guys? 

RC: Certainly when the FDA decided that they wanted to regulate, in 2003. Before the regulation was enforced in 2006, the industry said we need to do something to make sure all the companies are measuring the same things the same way, getting the same answers. It's always an issue of trade between buyers and sellers.

LD: Oh, right, I imagine a food manufacturer would get mad if trans fats showed up in their products because they bought raw materials that weren't supposed to have them but did.  

RC: The FDA doesn't allow you to have that excuse, unfortunately. The usual excuse is, I measured it your way, you measured it your way.

LD: And how different are all the ways to replace trans fats? 

RC: I think it's a science, though it might be a bit of an art. You're looking for functional performance. So if the fat helps your cake rise, or helps something stick together, and if you change it, you might have inconsistencies in food. The trick of reformulation is to get the same sensory characteristics.

LD: And what's the most successful way of doing that? I've heard of replacing them with palm oil or corn oil, but that doesn't seem like it could possibly be the same. 

RC: There appear to be two approaches: One is to replace the oil source to one that doesn't contain trans fatty acids. And there are many different types of oils with many different properties, and so you can mix and match the oils, basically. The other approach appears to be to use emulsifying agents that end up giving you the same sort of structure that's not fat related at all.

It's in the small print at the bottom of the label. The last 10 items are the ones that do most of the work.

Cantrill noted that he is a fats expert, not an emulsification expert, but that's basically how substituting works.