Escherichia coli O121 outbreak associated with raw milk Gouda-like cheese in British Columbia, Canada, 2018

Abstract

Background: In 2018, a Shiga toxin–producing Escherichia coli O121 outbreak that affected seven individuals was associated with raw milk Gouda-like cheese produced in British Columbia, Canada. Objectives: To describe the E. coli O121 outbreak investigation and recommend greater control measures for raw milk Gouda-like cheese. Methods: Cases of E. coli O121 were identified through laboratory testing results and epidemiologic surveillance data. The cases were interviewed on exposures of interest, which were analyzed against Foodbook Report values for British Columbia. Environmental inspection of the dairy plant and the cheese products was conducted to ascertain a source of contamination. Whole genome multi-locus sequence typing (wgMLST) was performed on all positive E. coli O121 clinical and food isolates at the provincial laboratory. Results: Four out of the seven cases consumed the same raw milk Gouda-like cheese between August and October 2018. The implicated cheese was aged longer than the required minimum of 60 days, and no production deficiencies were noted. One sample of the implicated cheese tested positive for E. coli O121. The seven clinical isolates and one cheese isolate matched by wgMLST within 6.5 alleles. Conclusion: Raw milk Gouda and Gouda-like cheese has been implicated in three previous Shiga toxin–producing E. coli outbreaks in North America. It was recommended product labelling to increase consumer awareness and thermization of milk to decrease the risk of illness associated with raw milk Gouda and Gouda-like cheese.

Heat induced inactivation of microorganisms in milk and dairy products

“…To improve the food safety confidence in reducing bacterial counts in raw cheese milk, thermisation has been used in the USA. The thermisation step allows the final product to still meet the labelling requirements for the raw milk cheese designation (Johnson, Nelson, & Johnson, 1990), and has been recommended by Canadian regulators to increase the microbial safety of Gouda or Gouda-like cheeses (Boyd et al, 2021). Among >900 USA artisan, farmstead, and specialty cheese producers surveyed in 2018, 50% used raw (no heat treatment) and 17% used thermised (some heat treatment but below legal pasteurisation requirements) milk in cheesemaking, up from 32% to 6%, respectively, as reported in 2016 (American Cheese Society, 2016Society, , 2018.…”

Mild Heat Treatment and Biopreservatives for Artisanal Raw Milk Cheeses: Reducing Microbial Spoilage and Extending Shelf-Life through Thermisation, Plant Extracts and Lactic Acid Bacteria

“…Nonetheless, consumption of raw milk cheeses may pose health safety issues due to the possible presence of pathogenic bacteria in raw milk that can remain viable during manufacture and through ripening [5][6][7]. The consumption of this type of dairy product has caused a few outbreaks [8][9][10][11][12], thus highlighting the need for preservation strategies to improve the microbial safety of raw milk cheeses.…”

Comparative genomic and phenotypic analyses of the virulence potential in Shiga toxin-producing Escherichia coli O121:H7 and O121:H10

“…STEC O121 is among the top six non-O157 serogroups that are most frequently associated with severe disease in humans ( Brooks et al., 2005 ; Gould et al., 2013 ; Luna-Gierke et al., 2014 ). Outbreaks of STEC O121 infection have been reported worldwide with a HUS rate ranging from 7.1% to 27.3% ( McCarthy et al., 2001 ; Yatsuyanagi et al., 2002 ; Luna-Gierke et al., 2014 ; Crowe et al., 2017 ; Morton et al., 2017 ; Boyd et al., 2021 ). The serotype O121:H19 is one of the non-O157 serotypes most frequently associated with HUS ( Kappeli et al., 2011 ), and the predominant serotype in the STEC O121 environmental isolates ( Carter et al., 2019 ).…”