Poster prepared by Silvie Mireille Kouamé-Sina, Kohei Makita, Delia Grace, Adjehi Dadié, Marcellin Dje and Bassirou Bonfoh for the 5th Congress of European Microbiologists (FEMS 2013), Leipzig, Germany, 21-25 July 2013.

1. Milk consumption patterns
The proportion of milk consumed raw (not boiled) in people who consume milk, after purchase
was 51.6% (90% CI, 45.7% to 57.4%). The number of daily consumers in Abidjan per day is esti-
mated at 2,180.
Hazard identification
Analysis of the milk showed the presence of one or more of the three pathogens (E. coli, S. aureus,
and Enterococcus) in 76.5% of milk samples (observed prevalence). The prevalence rates of E. coli,
S. aureus, and Enterococcus in marketed milk were 70.5%, 17.6%, and 58.8%, respectively.
After simulations (5000 iterations), the probability that marketed milk is contaminated with
at least one of these bacteria was 73.7% (90%CI, 56.1% to 88.3%) (fig 3). The specific probabilities
of contamination with E. coli, S. aureus, and Enterococcus were 68.4% (90% CI, 50.2% to 84.4%),
21.5% (90% CI, 8.0% to 37.7%), and 57.9% (90% CI, 39.2% to 75.6%) respectively.
The average bacterial load of marketed raw milk was 105
cfu/mL.
FIG 1. Milk value chain in urban and periurban areas of Abidjan.
Various modes of milk sales were observed: by traders with milk cans on a bicycle, by mo-
bile street vendors, and by roadside vendors. None of the milk sold was refrigerated.
FIG. 3. Simulation of frequency of contamination of raw milk by pathogens
FIG 2. Fault tree showing events leading to gastroenteritis. P, prevalence
Description of the informal production chain for milk
Fault tree of events leading to gastroenteritis after milk consumption
Context
In Côte d’Ivoire, people with gastrointestinal symptoms (diarrhoea, vomiting, stomach cramps, fever) rarely go to the hospital, because they lack medical coverage;
therefore, the rate of food poisoning is underreported. The dairy production in Côte d’Ivoire is in the informal smallholder sector, using traditional practices. Unhy-
gienic hand milking by producers as well as transportation and sales under hot ambient temperatures are likely to lead to milk of poor hygiene being sold. There are
several published quantitative risk assessments for dairy products, but the method has not been widely applied in developing countries. We report a risk assessment
carried out to answer the following question: What is the risk of ingestion of raw milk contaminated by a group of pathogens (Staphylococcus aureus, E. coli, and En-
terococcus spp.) for consumers in Abidjan, Côte d’Ivoire?
Bacterial risk assessment
of milk produced locally
in Abidjan, Côte d´Ivoire
Sylvie Mireille Kouamé-Sina1,4*
, Kohei Makita2
, Delia Grace3
, Adjehi Dadié4
, Marcellin Dje4
, & Bassirou Bonfoh1
1. Centre Suisse de Recherches Scientifiques en Côte d’Ivoire / 01 BP 1303 Abidjan 01, administration@csrs.ci - www.csrs.ch
2. School of Veterinary Medicine, Rakuno Gakuen University, Ebetsu, Japan.
3. International Livestock Research Institute ILRI, Nairobi, Kenya.
4. Nangui Abrogoua University, Abidjan, Côte d’Ivoire.
Corresponding author:
Sylvie Mireille Kouamé-Sina
kouamesylviemireille@yahoo.fr / Cel: +225 01 50 46 43
Methodology
We carried out structured interviews and focus group discussions with farmers (n = 15), vendors (n = 17), and consumers (n = 188) to characterize dairy production sys-
tems and milk consumption behavior. Microbiological sampling was conducted at different points between milking and sale. A risk assessment of the health impacts of
consumption of local raw milk was performed, following the first two steps of the Codex Alimentarius nomenclature: hazard identification and exposure assessment. We
identified S. aureus, E. coli, and Enterococcus spp. as hazards of concern because they cause food-borne infections in Côte d’Ivoire. A risk model was developed, and the
risk of consuming contaminated raw milk was estimated by Monte Carlo simulation.
Results
Exposure assessment
The prevalence of marketed milk not meeting standards of microbiological quality was 58.1%
(90% CI, 44.0% to 75.8%). The probability of ingestion of marketed raw milk not meeting stand-
ards of microbiological quality for this group of pathogens was 29.9% (90% CI, 20.1% to 39.5%).
We estimated that 652 consumers per day (90% CI, 458 to 881) in the Abidjan area ingest con-
taminated milk not meeting standards of microbiological quality.
This study was conducted with financial support from the International Foundation for Science
(IFS) (ref: E/4488-1), the International Livestock Research Institute (ILRI)/Deutsche Gesellschaft
für Internationale Zusammenarbeit (GIZ) GmbH through the “Safe Food, Fair Food” project,
and the Consortium Afrique One.
FEMS 2013, 5th
Congress of European Microbiologists,Leipzig, Germany, July 21-25 2013
Acknowledgements
Likelihood
Prevalence
Nangui Abrogoua University