CDC just released a report detailing Listeria outbreaks in the United States, 2009-2011. In this time frame, ,1651 cases were reported nationally.
In summary, Listeria monocytogenes is a foodborne pathogen that primarily impacts those in high risk groups – elderly, immunocompromised, and pregnant women. Listeria infection in these individuals leads to bacteremia (bacterial blood infection), meningitis, and death (mortality rate of 21%).
Soft cheeses and cheeses made from unpasteurized milk are the primary vehicles, although there have been cases related to produce (cut celery and cantaloupe). So for high risk groups, individuals in these high risk groups may want to forgo the soft cheeses, cheeses made from unpasteurized milk, and unpasteurized milk.
I think it is important to note what is not on list of responsible food items in this reporting period – deli meats. The meat industry has done a good job in reducing the risk associated with those ready-to-eat meat items. But work needs to continue with all refrigerated RTE items that can support the growth of Listeria. Recently, an interagency report on the risk of Listeria in Retail Delicatessens (
http://pennstatefoodsafety.blogspot.com/2013/05/risk-assessment-of-listeria-in-retail.html) highlighted the practices retail stores can take to reduce the risk of Listeria contamination.
CDC MMWR Repot http://www.cdc.gov/mmwr/preview/mmwrhtml/mm62e0604a1.htm?s_cid=mm62e0604a1_wVital Signs: Listeria Illnesses, Deaths, and Outbreaks — United States, 2009–2011Early Release
June 4, 2013 / 62(Early Release);1-5
Abstract
Background: Older adults, pregnant women, and persons with immunocompromising conditions are at higher risk than others for invasive Listeria monocytogenes infection (listeriosis), a rare and preventable foodborne illness that can cause bacteremia, meningitis, fetal loss, and death.
Methods: This report summarizes data on 2009–2011 listeriosis cases and outbreaks reported to U.S. surveillance systems. The Listeria Initiative and PulseNet conduct nationwide surveillance to rapidly detect and respond to outbreaks, the Foodborne Diseases Active Surveillance Network (FoodNet) conducts active, sentinel population–based surveillance to track incidence trends, and the Foodborne Disease Outbreak Surveillance System (FDOSS) receives reports of investigated outbreaks to track foods and settings associated with outbreaks.
Results: Nationwide, 1,651 cases of listeriosis occurring during 2009–2011 were reported. The case-fatality rate was 21%. Most cases occurred among adults aged ≥65 years (950 [58%]), and 14% (227) were pregnancy-associated. At least 74% of nonpregnant patients aged <65 years had an immunocompromising condition, most commonly immunosuppressive therapy or malignancy. The average annual incidence was 0.29 cases per 100,000 population. Compared with the overall population, incidence was markedly higher among adults aged ≥65 years (1.3; relative rate [RR]: 4.4) and pregnant women (3.0; RR: 10.1). Twelve reported outbreaks affected 224 patients in 38 states. Five outbreak investigations implicated soft cheeses made from pasteurized milk that were likely contaminated during cheese-making (four implicated Mexican-style cheese, and one implicated two other types of cheese). Two outbreaks were linked to raw produce.
Conclusions: Almost all listeriosis occurs in persons in higher-risk groups. Soft cheeses were prominent vehicles, but other foods also caused recent outbreaks. Prevention targeting higher-risk groups and control of Listeria monocytogenes contamination in foods implicated by outbreak investigations will have the greatest impact on reducing the burden of listeriosis.
Implications for Public Health Practice: Careful attention to food safety is especially important to protect vulnerable populations. Surveillance for foodborne infections like listeriosis identifies food safety gaps that can be addressed by industry, regulatory authorities, food preparers, and consumers.