Kinkese et al.,2018 Contamination of Complementary Weaning Foods for Children with Escherichia coli and Salmonella species in Lusaka District, Zambia

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Keywords: Escherichia Coli, Salmonella, Bacterial Contamination, Complementary Foods, Weaning, Children, Suburbs and Lusaka


Background: Complementary food is any food other than breast milk given to children in the complementary feeding period. The magnitude of foodborne diseases in Zambia is not fully known. We examined Escherichia coli (E. coli) and Salmonella levels of contamination in complementary foods. These are some of the most harmful potential pathogens that can cause foodborne diseases of human or animal origin. A selected bacterium was analysed for antibiotic susceptibility and their capacity to produce extended spectrum beta-lactamase (ESBL). The aim of the study was to critically explore and investigate the safety of complementary weaning foods in households in Lusaka district.

Methods: A cross-sectional study was conducted over a period of nine (9) months from October 2016 to July 2017. The study sites were in Lusaka district which was clustered into wards then finally into households. At every randomly selected household, the eligible mother/caretaker was asked to submit the complementary foods that she was giving the child, and sampling was done aseptically by taking a portion. A multi-stage sampling type was employed to collect complementary foods which were kept in various types of storage containers: Some (24%) of respondents used refrigerators while others respondents (10.1%) kept complementary foods on vegetable racks. The foods were prepared by boiling maize meal or cassava meal with the addition of pounded ground nuts, sugar, salt and butter. A high confidence limit of 95% (0.95) was calculated.

Results: Out of 244 (100%) complementary food samples contaminated with bacteria, 91 (37.3%) had E. coli and 38 (15.6%) had Salmonella. The rest – 115 (47.13%) – food samples were contaminated with other bacteria such as Staphylococcus 30 (12.30%), Bacillus 68 (27.87) and Streptococcus 17(6.97%). Of the food, 172 (70.49%) were energy foods, 56 (22.95%) protein foods and 16 (6.56%) other food types. Mtendere ward had more E. coli contamination over 6 X 104 cfu/g, while Kanyama/Mbasela had around 4 X 104. E. coli was found most resistant to metronidazole 72 (94.74%) and Ceftazidime 59 (77.63, while Salmonella isolates were resistant to metronidazole 30 (96.77%), Ceftazidime 25 (80.65%) and penicillin 24 (77.42%).

Conclusion: Complementary foods in this study of Lusaka district were generally contaminated with bacteria. The main one being Escherichia coli which is ubiquitous in nature and the commonest contaminant, followed by Salmonella spp. Contaminated weaning foods are still an unresolved problem in Zambia. Furthermore isolated E. coli and Salmonella exhibited resistance to metronidazole and Ceftazidime. The results raises some serious concerns as the drugs used for first choice for enteric infections. It is recommended that further studies should update the infants/children diarrhoeal cases in the Lusaka district and tackle the problem of antibiotic drug resistance with a view of vaccine development.