Salmonella and leafy greens eaten raw tops risk assessment model

Researchers ranked specific food/pathogen combinations most often linked to human cases originating from foods of non-animal origin (FoNAO) in the EU.

It was followed by (in equal rank) Salmonella with bulb and stem vegetables or tomatoes or melons, and pathogenic E. coli and fresh pods, legumes or grains.

Pathogen/food risk criteria​

A semi-quantitative model was developed using seven criteria: strength of associations between food and pathogen based on foodborne outbreak data from EU Zoonoses Monitoring (2007–2011), incidence of illness, burden of disease, dose–response relationship, consumption, prevalence of contamination and pathogen growth potential during shelf life.

For each criterion, available data was grouped into scoring categories, which were defined and assigned a numerical score - higher scores corresponded to prioritised food/hazard combinations.

When insufficient quantitative data was available, qualitative data based on, for example, expert opinion was used, said the researchers.

A risk ranking tool (RRT) was developed for pathogens in FoNAO involved with foodborne disease outbreaks caused by viruses, bacteria or parasites in the EU.

The approach identified pathogen–food commodity combinations associated with human disease using data from reported foodborne outbreaks, RASFF notifications, scientific literature and expert opinion.

Outcomes were then derived from severity of the health effect for each hazard, the degree of under-reporting and incidence of illness, the criteria related to the probability of exposure and contamination, the dose–response relationship, growth potential of the hazard and shelf life of the commodity.

BIOHAZ panel work​

FoNAO was associated with 10% of outbreaks, 26% of cases, 35% of hospitalisations and 46% of deaths in all reported foodborne outbreaks reported in the EU from 2007-2011, according to the EFSA Panel on Biological Hazards (BIOHAZ) in 2013.

Based on the data presented from the panel’s findings 10 very strong, 14 strong, 31 moderate and 54 weak associations between FoNAO types and specific pathogens were identified.

Food production practices were not considered because information was not available in the databases on outbreaks or consumption.

It was not possible to include more than limited information on processing, storage conditions and food preparation habits, although these steps may strongly influence survival and growth of microbiological hazards.

Researchers said that 45% of all reported outbreaks implicating FoNAO from 2007–2011 were excluded from the risk ranking model, according to exclusion criteria established to put the focus on ready-to-eat unprocessed products.

They added that future outbreaks are likely to impact on the ranking orders, and results should be seen as a snapshot of the situation in the study period and do not have any predictive value on potential future outbreaks.

“Despite the inherent assumptions and limitations, this risk model is considered a tool for risk managers, as it allows ranking of food/pathogen combinations most often linked to foodborne human cases originating from FoNAO in the EU.” ​

Source: International Journal of Food Microbiology Volume 195, 16 February 2015, Pages 9–19

Online ahead of print, DOI: 10.1016/j.ijfoodmicro.2014.11.005​

“Risk ranking of pathogens in ready-to-eat unprocessed foods of non-animal origin (FoNAO) in the EU: Initial evaluation using outbreak data (2007–2011)”​

Authors: M.T. Da Silva Felício, T. Hald, E. Liebana, A. Allende, M. Hugas, C. Nguyen-The, G. Skoien Johannessen, T. Niskanen, M. Uyttendaele, J. McLauchlin