dc.description.abstract | The steady increase in the utilization of meat products has led to a rise in demand as
well as its market price. Substitution of meat from animal species of higher
commercial value with those from cheaper or undesirable species occurs often,
posing ethical, religious, and dietary concerns. In Nairobi and Naivasha, there have
been reports of bushmeat and undeclared species sold to unsuspecting customers.
The aim of the study was to identify the vertebrate sources of meat sold to consumers
in Nairobi hence determining if there was any species substitution in the meat value
chain; and also, to detect potential pathogens in the meat sold to consumers.
A total of 115 meat samples were obtained randomly from butcheries in Burma
Market, Nairobi, and its surrounding areas. Additionally, seven goat samples were
obtained from Kiamaiko as controls. Extraction of DNA from these samples was
done using the ISOLATE II Genomic DNA extraction kit (Bioline, UK) and
determination of species and bacterial screening carried out. Furthermore, ninetynine
meat samples similarly obtained from Naivasha butcheries and stored at -80°C
were also analyzed for presence of bacterial pathogens, making the total number of
samples 221. Species identification was done using high-resolution melting (HRM)
analysis of the PCR products. Three mitochondrial DNA markers, cytochrome
oxidase subunit 1 (CO1), cytochrome b (cyt b), and 16S rRNA genes were targeted
to identify vertebrate species. Presence of selected bacterial zoonotic pathogens was
evaluated through analysis of HRM of PCR products targeting the genes bcsp31,
secYIV, PL3 and IS1111 for Brucella spp., pathogenic Leptospira spp., Bacillus
anthracis and Coxiella burnetii respectively. Additionally, sequencing of PCR
amplified products using universal 16S rRNA was utilized to screen for more
bacterial contaminants.
The study detected incidence of species substitution in the meat value chain, with
15/115 samples collected in Nairobi found to be substituted. Presence of zoonotic
bacteria that pose a risk to individuals involved in the meat value chain was also
detected with 27/221 of the samples being positive for pathogenic Brucella, and
1/221 of the samples being positive for Leptospira interrogans. None of the samples
were positive for Bacillus anthracis or Coxiella burnetii. Using the universal 16S
rRNA gene primers allowed the amplification of food-borne pathogens including
Lactococcus garvieae, Clostridium spp. and Aeromonas caviae in 3% of the
samples, where 7/221 samples were found to have bacteria that are enteropathogenic
or enterotoxin producing. These findings reveal that there may be loopholes in the
meat value chain that could place consumers at risk of allergic reactions due to
undeclared meat species, and to public health because of the zoonotic and foodborne
bacterial pathogens present. However, no correlation could be found between
species substitution and pathogens. | en_US |