Bacillus cereus is a group of ubiquitous facultative anaerobic spore forming Gram-positive rods commonly found in soil. It has been detected and implicated in several contaminated food products and raw milk in dairy farms and it causes foodborne gastroenteritis by producing several toxins. This study is aimed at characterizing virulence determinants of B. cereus from cow‟s raw milk. A total of 400 raw milk samples were collected in Fort Hare Dairy Trust and Middledrift Dairy Farm; and cultured on Polymyxin pyruvate Egg-Yolk Mannitol Bromothymol Agar (PEMBA) for 48 hours at 37°C. DNA was isolated from the isolates and 16S rDNA was amplified and sent to Central Analytical Laboratory for sequencing. The gyrB gene of B. cereus was also used to confirm the identity of the isolates. Antibiotic susceptibility profiles of the isolates together with virulence genes were investigated. Multilocus Sequence typing was used to investigate the genetic relatedness of some selected isolates. Furthermore, spores of the isolates were produced, harvested and their concentrations determined. All (100%) of the isolates were identified as having a 96-99% similarity to B. cereus, B. thuringiensis and B. anthracis using sequencing; while gyrB gene was observed in all (100%) of the isolates. Three virulence genes nheA, nheB, nheC encoding for non haemolysin enterotoxin were amplified in all (100%) the isolates. All (100%) of the isolates were susceptible to doxycycline, gentamycin, tetracycline, ciprofloxacin, chloramphenicol and streptomycin. Resistance to rifampicin and penicillin G was predominant with equal rate of 100%, while susceptibility to erythromycin, clindamycin and doxycycline ranged from 60% to 100%. The selected isolates were related and are descendants of the same ancestor. All (100%) the isolates produced spores. The B. cereus isolates contain virulence genes, has multiple antibiotic drug resistance and produce spores, which poses a health risk to the public and cannot be used as probiotics.

This study was concerned with establishing the extent to which various components of the environment were exposed to the three toxic minerals, arsenic, mercury and lead. The concentration of these three elements were determined in groundwater and surface water, soil, plants, animals such as goats, and humans in potentially contaminated areas in the Limpopo Province of South Africa. The focus of the study was to assess the possible exposure to infants through ingestion to arsenic, mercury and lead. Comparison of the mineral content of water at the study sites with international and national drinking water standards, indicated water from Rooiberg, Leeupoort and Gravelotte are not fit for human consumption due to high arsenic and lead concentrations. Water at Gravelotte also has unacceptably high levels of mercury. The soil, plants, goat’s milk and mother’s milk at Rooiberg have higher levels of arsenic and lead than have been recorded for many other countries. Mother’s milk and goat’s milk are the main sources of arsenic, lead and mercury contamination at Rooiberg. It is therefore newborns and toddlers who are most at risk from exposure to arsenic and lead. This is a cause for environmental and health concerns, but as this research is only a base-line study, it is imperative that more comprehensive surveys of potentially toxic mineral contamination be conducted in the province. / Environmental Sciences / (M.Sc. (Environmental Science))

This study was concerned with establishing the extent to which various components of the environment were exposed to the three toxic minerals, arsenic, mercury and lead. The concentration of these three elements were determined in groundwater and surface water, soil, plants, animals such as goats, and humans in potentially contaminated areas in the Limpopo Province of South Africa. The focus of the study was to assess the possible exposure to infants through ingestion to arsenic, mercury and lead. Comparison of the mineral content of water at the study sites with international and national drinking water standards, indicated water from Rooiberg, Leeupoort and Gravelotte are not fit for human consumption due to high arsenic and lead concentrations. Water at Gravelotte also has unacceptably high levels of mercury. The soil, plants, goat’s milk and mother’s milk at Rooiberg have higher levels of arsenic and lead than have been recorded for many other countries. Mother’s milk and goat’s milk are the main sources of arsenic, lead and mercury contamination at Rooiberg. It is therefore newborns and toddlers who are most at risk from exposure to arsenic and lead. This is a cause for environmental and health concerns, but as this research is only a base-line study, it is imperative that more comprehensive surveys of potentially toxic mineral contamination be conducted in the province. / Environmental Sciences / (M.Sc. (Environmental Science))

Thesis (M. Tech.) -- Central University of Technology, Free State, 2008 / Local government (LG) is under increasing pressure from the milk industry and consumers regarding their ability and willingness to carry out their mandate with regard to the quality control of milk, especially in the informal sector. The government and the milk industry currently have programmes underway to stimulate economic activities in the informal sector, targeting emerging cattle farmers for the production of milk as part of government’s Accelerated Shared Growth Initiative of South Africa (ASGISA). These initiatives further increase the number of informal milk producers and distributors, which holds a further challenge to regulatory authorities. At the same time, the quality of milk from the informal milk-producing sector poses a serious public health concern. Most of the milk produced and sold by the informal sector is raw (unpasteurised), which does not meet the minimum statutory requirements, and the milking practices applied by the informal sector also do not comply with best practice compliance standards. Local authorities (LAs) are statutorily responsible for registering milking parlours and controlling milk hygiene quality from production stage to purchase stage in order to ensure safe and wholesome dairy products to the consumer. Therefore, LG should play an increasingly important role in ensuring that safe and wholesome milk is produced and distributed to the consumers. All metropolitan municipalities (metros) and district municipalities (DMs) should be authorised by the Ministry of Health to enforce the Foodstuffs, Cosmetics and Disinfectants Act, 1972 (Act 54 of 1972) through their authorised officials – mainly environmental health practitioners (EHPs). Secondly, LG should have specific programmes, systems and resources to register, monitor, evaluate and control milk production and distribution outlets for continued compliance