Bacteriological Analyses of Weaning Foods and Growth Potential of Some Food borne Pathogens in Weaning Foods

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Addis Ababa University


One hundred samples of feeding-bottles were collected from infants and young children coming to four clinics in Addis Ababa, from November, 1996 to April, 1997. Information on sex, age, number of bottles used, educational status of the mother and ingredients of bottle content were collected through interview. The bacteriology of these samples was analysed using standard microbiological techniques. The analyses showed that all the samples had heavy bacterial contamination, the mean count being in the levei of 107 c.f.u / ml. Only 17% of the samples had count l'O6 c. f. u /ml. The two most *commonly encountered bottle contents (cow's milk and cereal blend) were the most heavily contaminated. About 52% of the milk and 93% of cereal blend had count more than 107 c.f.u/ml. The contamination level was found to be affected by ingredients of bottles used and educational status of mothers. About 90% of the samples prepared by illiterate mothers had count over 107 c.f.u/ml. The percentages for elementary and high school educated mothers for the corresponding load were 85 and 79, respectively. Three hundred and sixty-nine bacterial isolates, grouped into 12 genera were identified from the bottle content. Thirty-seven per cent of the samples had 3 isolates, whereas 21% and 16% of the samples were contaminated with 4 and 2 isolates, respectively. The dominant organisms were coliforms (34%) followed by Staphylococci (28 %), Bacillus spp . (19%) Micrococcus spp. (14%) and other (3%). Three isolates of Salmonella spp. of the same serogroup were also identified. Cow's milk harboured 219(59%) of the isolates followed by gruel made of cereal blend(16%). A total of 30 factory-produced weaning foods (product A, B and C), and 20 of the two most frequently encountered home-made bottle-contents (cow's milk and cereal blend) were prepared at home by mothers under close supervision. The bacteriological analyses of these foods showed that only 30% of the factory-produced weaning foods had bacterial count over 102 c.f.u/ ml(g). The count from the two home-made bottle contents was also low; only 15% of the samples had bacteria 102 c.f. u/ml. These signifies that food handling and the gap between consumption and preparation must be important in this regard. The organisms isolated from the above 50 samples were Bacillus spp., for they were the only organisms that could tolerate the heat treatment. The growth potential of Salmonella sp. in products 'C' and cereal blend was determined. It was found out that it reached to a level of 107 c.f.u ./ml(g) in 12 hours and 10s c.f.u/ml(g) in 16 hours. If weaning foods have initial contamination of 103 c.f.u./ml (g) (which by itself is beyond the threshold level for infants) it reaches to unacceptably high level within 8 hours (10G c.f.u/mlg)In order to intervene with food borne diseases of infants and children, mothers must be taught of food safety principles. Increasing the number of bottles used to feed infants to three or more could also be helpful in reducing food borne bacterial contamination . More important is teaching and encouraging mothers to consider the use of fermented food products as alternatives, which are cost-effective means of reducing bacterial pathogens in weaning foods.