Health Safety

A CDC Expert Explains Why You Probably Shouldn’t Be Too Worried About Listeria in Ice Cream

"It's a wake-up call to the ice cream industry."

Within the past month, two ice-cream companies have instated massive recalls owing to outbreaks of listeria — a bacteria that’s potentially harmful, especially to pregnant women, the elderly, and anyone with a compromised immune system. Both Jeni’s Splendid Ice Cream and Blue Bell yanked every single one of their products off of shelves. What gives? Is ice cream now something to be avoided because of possible food-borne illness? Grub called up Dr. Robert Tauxe, the deputy director of the Center for Disease Control’s Division of Foodborne, Waterborne, and Environmental Diseases, to find out if America’s favorite summertime dessert is in jeopardy.

I’ve eaten about six pints of Jeni’s ice cream over the past month. Am I going to be okay?
First of all, listeria itself is a rare cause of food-borne infection. We have about 800 cases reported each year, and we think there’s another 800 that are perhaps misdiagnosed, but severed. So our estimate is 1,600 cases a year. Remember that this is only particularly dangerous for the part of the population whose immune systems may not be working right — the elderly, pregnant women, and people who have diseases.

It used to be that the outbreaks were mostly from either soft cheeses — especially the Hispanic-style cheeses like queso fresco — or processed meat. But the processed-meat industry took all this very seriously and made enormous strides to reduce contamination in processed meats. We still do sometimes have an outbreak that relates to cheese.

So is it just a coincidence that there have been outbreaks at two companies?
But what has happened here, with ice cream, is that we have introduced a new technology for looking for outbreaks. We’re finding more outbreaks than we used to find, and some of them are linked to foods that we had never linked to listeria before. Now we’ve had an episode with ice cream. We don’t think of ice cream as particularly hazardous, but problems were identified and investigated partly because we have better ways of detecting them.

What’s this new way that you’re identifying outbreaks?
The usual order is you have a group of sick people with strains of listeria, and you interview them and see whether their strains are closely related. Then, our investigators — our disease detectors — try to find out what that is that they ate in common. Now, in the case of the ice cream, this was backwards. For reasons unrelated to human health, a laboratory in South Carolina decided to culture some ice cream, because it was demonstrating its proficiency at culturing food — not because it was suspicious of the ice cream. And then, they researchers found listeria in the ice cream.

We have a database that all the state laboratories, as well as the CDC laboratory, use. The South Carolina researchers could see that as soon as they put some of their ice cream strain patterns into the pulse net database, some human illnesses seemed to match. Those human illnesses were in Kansas, and they had all been at the same hospital in the same year. So in this case, something that was found in food rather coincidentally matched up with a strain of germs in the sick people.

There was the sampling of ice cream from Blue Bel,l which clearly identified a problem, and there was the sampling out in Nebraska that identified a problem with Jeni’s, but we think of ice cream as something that should, in general, be quite safe. I view these as two unfortunate coincidences. But if I were part of the ice-cream industry, I would certainly be talking to the food-safety manager at my plant, and I’d be very clear about the processes in place.

What were these ice-cream-makers doing wrong?
I don’t know — I haven’t heard what was learned in the investigation. But at some point, ice cream is a processed food. It’s just important to have an ongoing process to make sure that any listeria that might show up does not find a place in a piece of equipment, where it can stay for a long time and contaminate food. This is certainly something that the processed-meat industry knows by heart — how to be totally scrupulously hygienic. I think it’s a wake-up call to the ice-cream industry.

How soon after you eat something contaminated can you tell if you’re sick?
We call that the incubation period, and for most of the illnesses that we get from food, it’s a matter of just a couple of days. But for listeria, it can be several weeks before the person becomes sick — as long as 70 days.

Oh, wow! I didn’t know that. I’ve eaten most of my pints recently.
And enjoyed them thoroughly, I’m sure.

Someone actually gave me the ice cream as an apology gift. “I’m sorry I messed up — here’s listeria.”
You might want to ask for a replacement gift! Our advice to you, or to anyone that still has products in their freezer that have been recalled, is to dispose of it all. If you don’t have any of the symptoms of listeria, there’s really nothing that has to be done. And if you’re not in one of the high-risk groups, chances are pretty good that you’re not going to get sick.

But we’re not sure, because it’s not always the high-risk groups. What we tell people who are worried because they consumed the food is that if they develop symptoms that include a high fever, a headache, and aches and pain in the body, they should see their physician. There’s no treatment that you can do ahead of time.

A CDC Expert Explains Why You Probably Shouldn’t Be Too Worried