Association between German cockroaches (Blattella germanica) and street food vending: Implications for food safety in Botswana

Abstract:
As a result of the rapid rate of urbanization in Botswana, street food vending has become very popular as it supports a large number of the population with affordable, nutritious foods. There has been an associated increase in the number of cockroaches around vending sites in the streets. Cockroaches are also abundant in the homes, some of which serve as food preparation areas for street foods by ambulatory vendors. German cockroaches (Blattella germanica) have become a common site all over the city. German cockroach egg cases, nymphs and adults were trapped in homes in various localities of Gaborone; the capital city of Botswana using traps. Traps were also set up in street food vending sites. In the homes, a mean trap catch of 422 cockroaches per week per locality was recorded from 1844 traps. The prevalence of cockroach infestation in the home can be given as kitchen 19 %; food storage room 16 %; bathroom 15 %; bedroom 15 %; lounge 14.8 %; toilet 12 %; dining room 6.6 %; passage 1.7 %. Insects trapped from street food vending sites in November/December 2003: German cockroach 88 %; Crematogaster sp. 2.6 %; Lucilia sp. 2.5 %; Musca domestica 2.2 %; Calliphora sp. 2.0; sugar ant 1.2 %; Platothereus sp. 0.8 %; Apis mellifera 0.5 %; Tribolium spp. 0.1 %; cricket 0.09 %; Drosophila melanogaster 0.05 %. The distribution of German cockroaches trapped in January/February, 2005 from street food vending sites in four localities was: Nymph 68.1 %; adults 31.9 %. The sex ratio of males to females was 1.3: 1. A different insect profile appears to exist in non-food vending sites. Cockroaches were subjected to microbiological tests using various media, for culturing and API and BIOLOG systems for identification. Scanning electron microscopy was used to determine the nature of contaminants associated with their body surfaces and fecal pellets. A large distribution of pathogenic and non-pathogenic bacteria, yeasts and moulds were identified. Some of the moulds associated with the cockroaches are mycotoxin producers. Concerns about the safety of street foods that are provided particularly by ambulatory vendors are raised and suggestions on the management of the problem are presented.