NEW YORK — The government is reporting an increase in food poisoning outbreaks that span multiple states, like the one that this week prompted Chipotle to close 43 of its restaurants in the Pacific Northwest.
On average, two dozen multi-state outbreaks occurred in the first five years of this decade. That's up from six a year from 1973 to 2010, the Centers for Disease Control and Prevention reported Tuesday.
The increase is partly due to better detection — using sophisticated testing, health officials can more easily link illnesses across state lines that may not have been grouped together in the past. And food industry consolidation means companies ship to wider networks of grocery stores and restaurants than in the past, so a tainted product can appear in more states now, health officials said.
Only one in 20 cases of U.S. food poisonings occur in outbreaks in which more than one person are sickened by a common food. Outbreaks can be local or scattered across two or more states.
The CDC analyzed 120 multi-state outbreaks from 2010 through 2014. Those outbreaks accounted for about 8,000 illnesses — that is, about 11 percent of outbreak-associated food poisonings.
But they tended to be severe cases. The multi-state illnesses included about a third of the outbreak-associated hospitalizations and more than half the deaths.
"Multi-state outbreaks have much more serious health effects than other outbreaks," said Dr. Tom Frieden, the CDC's director.
They tend to be caused by more lethal listeria, salmonella and E. coli germs, he said.
From 1973 through 2010, only 3 percent outbreak-associated food poisonings spanned multiple states. The proportions of hospitalizations and deaths tied to multi-state outbreaks were much lower.
One is the outbreak linked to the Chipotle restaurant chain, which has sickened at least 37 people in Oregon and Washington. Many had eaten at Chipotle locations during the previous few weeks. Victims had E. coli bacterial illness.
Health officials are still investigating, and have not determined what food was contaminated.