Bonfoh, Bassirou

Dadie, A.

Dje, K.M.

Grace, Delia

Kouame-Sina, S.M.

Makita, K.

Meile, L.

Yobouet, B.A.

CGSpace

Bacillus cereus risk assessment in raw milk consumed in the informal dairy sector in Côte d’Ivoire  Yobouet B. A., Kouamé-Sina S.M., Dadié A., Makita K., Grace D., Meile L., Djè K. M., and Bonfoh B.  bassaantoine2007@yahoo.fr / antoine.yobouet@csrs.ci          1 ICOPHAI    15th -17th September 2011  In Côte d’Ivoire as elsewhere in Africa, milk plays an important role in human nutrition   Formerly = consumed by people in rural areas of production   Now = milk is widely consumed in urban areas   Milk production activities are important in West Africa and generate significant income in rural households (34% of total income)       2 Background (1)    Unregulated informal  sector accounts for 80% of the channels of production,    distribution and marketing   Côte d’Ivoire is no exception to this rule:  92% dairy farmers own small subsistence farms and herders did not go to school and have no hygiene awareness  Background (2)  Currently no methods are applied by the actors in the production systems to substantially reduce the contamination.   Consequence:  Milk is contaminated with pathogens in general and in particular with Bacillus cereus considered as an emerging opportunistic pathogen and an indicator of environmental contamination.    B. cereus is one of the bacteria associated with food poisoning in humans and causes two types of foodborne illnesses:       A diarrheal intoxication      B. cereus  emetic toxin syndrome     The type of poisoning is determined by the kind of enterotoxin elaborated.     3      Therefore, what is the risk associated with the consumption of raw milk contaminated by B. cereus for the consumer in Côte d’Ivoire ?   Objectives  Assess the risk associated with B. cereus incurred to the consumer of raw milk traditionally produced in Abidjan.         4 Aims 5 Material and Methods (1) Sites Farms N = 15 Cows N = 119 Vendors N = 15 Port-bouet 4 21 6 Lièvre rouge 2 33 2 Songon-té 1 9 - Abobo derrière rail - - 7 Abobo N’dotré 8 56 - Samples to determine critical points 119 udder milk 14 herder’s bulk milk 17 retailer’s pooled milk Samples to identify sources of contamination 113 udder skin swabs 22 hand swabs of farmers 14 rinsing water for utensils  16 environment samples  5 samples of water used to clean material for milking in 5 farms - 5 sites of milk production and sale of raw milk were selected.  - Surveys were conducted with 15 herders, 15 vendors and 188 clients to identify  practices of breeders and vendors who have an influence on milk quality, mode of consumption of milk and  risk to the consumer. - 320 samples were sampled at all stages of the production chain of milk.  6 Material and Methods (2)  All the samples were analyzed to isolate and identify B. cereus  strains by classical bacteriological methods and by PCR    Virulence genes of these strains were determined by PCR    The sensitivity of the virulence strains to antibiotics commonly used to treat food poisoning was determined                   7 Results (1) Samples Percentage of samples contaminated (%) Mean count  (ufc/ml) Udder milk 26.9 4.2 x102  Herder's bulk milk 28.6 102  Retailer pooled milk 41.2 4.1x 103  Udder skin swabs 64.6 3x 103  Hand swabs of farmers 40.9 1.3x 102  Rinsing water for utensils  28.6 0.3 x102  Environment samples (Air) 56.3 0.7x 102  Water used to clean material for milking 60 6.7x 102  Sources of contamination by decreasing order of importance: Udder, water, Environment, Milk vendor containers, Hands of the milker (s) and Utensils  No hygienic practices before, during milking in between milking by milkers.  No cooling, pasteurization of milk after milking and milking was done in the mud and dung.   8 Results (2) Intensity  Diseases N = 24 (12.8) Less serious (still working) 13 (54.2) Moderately serious (stay at home) 8 (33.3) Serious (1 to 3 days in hospital) 3 (12.5) Symptoms  Case  (N = 37) Diarrhea  19 (51.4) Fever  5 (13.5) Stomach bloat 4 (10.8) Stomach pains  3 (8.1) Vomiting  3 (8.1) Nausea  1 (2.7) Headache 1 (2.7) Cough  1 (2.7) Exposure Sick people after milk consumption  Healthy people after milk consumption Total  Consumption of milk without thermal treatment  18 83 101 Consumption of milk after thermal treatment  6 81 87 Total  24 164 188 12.8%  of consumers reported they had food poisoning after consuming milk and diarrhoea was the most symptom reported. Severe cases requiring a stay of 1 to 3 days in hospital were reported by 12.5%  of those infected.   The probability of consuming milk contaminated with B. cereus was 22.2%; Foodborne disease occurrence for the consumer was significantly related to the consumption of unheated milk.  Chi square of Pearson = 5.01; Pc = 0.025; RR = 2.584; IC 95%: [1.074; 6.22] Results (3) 9 7 strains (7.9%) contained the 3 components of the HBL complex and in 2 strains (2.3%), the 3 components of the NHE complex. Only 1 strain (1.1%) contained simultaneously the 3 components of HBL and NHE complex.  All B. cereus group strains (88 strains) isolated were virulent and harbored at least one of the virulence genes by decreasing order hblD (79/88), cytK-2 (79/88), nheC (65/88), hblC (60/88), bceT (34/88), nheA (32/88), nheB (22/88) and hblA (12/88), all involved in the aetiology of diarrheal syndroms.  Results (4) 10 Antimicrobial agent Number  (%) of strains Sensible Intermediate Resistant Ampicillin (10 µg) 0 (0) 0 (0) 88 (100) Penicillin (10 U) 0 (0) 0 (0) 88 (100) Cefepime (30 µg) 0 (0) 0 (0) 88 (100) Chloramphenicol (30 µg) 5 (5.7) 47 (53.4) 36 (40.9) Ciprofloxacin (5 µg) 3 (3.4) 22 (25) 63 (71.6) Clindamycin (2 µg) 88 (100) 0 (0) 0 (0) Vancomycin (30 µg) 46 (52.3) 0 (0) 42 (47.7) Gentamicin (10 µg) 65 (73.9) 20 (22.7) 3 (3.4) Imipenem (10 µg) 42 (47.7) 36 (40.9) 10 (11.4) Tetracyclin (30 µg) 4 (4.5) 3 (3.4) 81 (92) Trimethoprim-sulfametoxazole (1.255 µg/23.75 µg)  0 (0)  0 (0)  88 (100) Erythromycin (15 µg) 32 (36.) 50 (56.8) 6 (6.8) They were resistant to several antibiotics including Tetracyclin (92%) and to a lesser extent to Ciprofloxacin (71.6%). The intermediately susceptible were detected with Vancomycin (52.3%), more and less Imipenem (47.7%).   All Bacillus cereus strains were susceptible to Clindamycin (100%) and to a lesser extent to Gentamicin (73.9%). 11 Conclusion     Some Bacillus cereus strains in milk and dairy products have beneficial effects and have been used as probiotics in the diets of immunocompromised people and against diarrhoea in young children.    However, Bacillus cereus isolated in informal dairy sector and milk in Côte d’Ivoire were multi-toxigenic and multiresistant to antibiotics and could be considered having a potential to cause food poisoning.   Multiresistance to antibiotics is not surprising considering how frequently these drugs have been used improperly in treating disease caused by pathogenic microorganisms at the farms and indicates the presence of other pathogenic bacteria in milk.   These strains pose a significant health risk to the consumer, transmission of antibiotic resistance to other microorganisms in the gastrointestinal being possible. www.csrs.ch Acknowledgements 

Bacillus cereus risk assessment in raw milk consumed in the informal dairy sector in Côte d’Ivoire

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Bacillus cereus risk assessment in raw milk consumed in the informal dairy sector in Côte d’Ivoire

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