38 sick, many pregnant in 2008 listeria in pasteurized cheese outbreak in Quebec; cross-contamination affected hundreds of retailers

Fall 2008 was a crappy time in Canada. While the Maple Leaf listeria-in-deli-meats outbreak would kill 23 and sicken 56, a listeria-in-cheese outbreak plagued Quebec (that’s in Canada, according to some), sickening lots, especially expectant mothers.

Amy was pregnant, heightening sensitivities.

At the time, public attention and concern in Quebec was far more focused on the plight of cheesemongers than the sick and several dead. Regulators took some tough steps to limit the outbreak but in a culture that values tradition, the Quebec Minister of Agriculture was forced to capitulate and change his tune from, "The province is not there to compensate. We aren’t an insurance company," to offering a three-year, $8.4-million aid package, along with $11.3-million in interest-free loans to Quebec’s small cheese producers and retailers less than three weeks later.

Government health-types in Quebec have now offered their version of events in the current issue of the Journal of Food Protection.

Although numbers of sick people were all over the place at the time, the researchers conclude there were 38 confirmed sick with the same strain of Listeria monocytogenes (LM P93) across Quebec from June through Dec. 2008, including 14 pregnant women and two babies born to asymptomatic mothers. There were two elderly deaths and three neonatal deaths.

The traceback of many brands of cheese that tested positive for LM P93 collected from retailers identified two cheese plants contaminated by L. monocytogenes strains on 3 and 4 September. PFGE profiles became available for both plants on 8 September, and confirmed that a single plant was associated with the outbreak. Products from these two plants were distributed to more than 300 retailers in the province, leading to extensive cross-contamination of retail stock.

So where is that local cheesemonger you know, trust and can look in the eye, getting their cheese from?

The abstract is below:

Widespread Listeriosis outbreak attributable to pasteurized cheese, which led to extensive cross-contamination affecting cheese retailers, Quebec, Canada, 2008
01.jan.12
Journal of Food Protection®, Volume 75, Number 1, January 2012 , pp. 71-78(8)
Gaulin, Colette; Ramsay, Danielle; Bekal, Sadjia
http://www.ingentaconnect.com/content/iafp/jfp/2012/00000075/00000001/art00011
Abstract:
A major Listeria monocytogenes outbreak occurred in the province of Quebec, Canada, in 2008, involving a strain of L. monocytogenes (LM P93) characterized by pulsed-field gel electrophoresis (PFGE) and associated with the consumption of pasteurized milk cheese. This report describes the results of the ensuing investigation. All individuals affected with LM P93 across the province were interviewed with a standardized questionnaire. Microbiological and environmental investigations were conducted by the Quebec’s Food Inspection Branch of Ministère de l’Agriculture, des Pêcheries et de l’Alimentation du Québec among retailers and cheese plants involved in the outbreak. Between 8 June and 31 December 2008, 38 confirmed cases of LM P93 were reported to public health authorities, including 16 maternal-neonatal cases (14 pregnant women, and two babies born to asymptomatic mothers). The traceback of many brands of cheese that tested positive for LM P93 collected from retailers identified two cheese plants contaminated by L. monocytogenes strains on 3 and 4 September. PFGE profiles became available for both plants on 8 September, and confirmed that a single plant was associated with the outbreak. Products from these two plants were distributed to more than 300 retailers in the province, leading to extensive cross-contamination of retail stock. L. monocytogenes is ubiquitous, and contamination can occur subsequent to heat treatment, which usually precedes cheese production. Contaminated soft-textured cheese is particularly prone to bacterial growth. Ongoing regulatory and industry efforts are needed to decrease the presence of Listeria in foods, including pasteurized products. Retailers should be instructed about the risk of cross-contamination, even with soft pasteurized cheese and apply methods to avoid it.

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About Douglas Powell

A former professor of food safety and the publisher of barfblog.com, Powell is passionate about food, has five daughters, and is an OK goaltender in pickup hockey. Download Doug’s CV here. Dr. Douglas Powell editor, barfblog.com retired professor, food safety 3/289 Annerley Rd Annerley, Queensland 4103 dpowell29@gmail.com 61478222221 I am based in Brisbane, Australia, 15 hours ahead of Eastern Standard Time