Microbiota and mycotoxins in traditional beer of the greater Kimberley area and associated brewing and consumption practices

Thesis (D. Tech.) -- Central University of Technology, Free State, 2008The purpose of this study was to evaluate brewing and consumption practices and to screen for micro-organisms and mycotoxins associated with traditional beer produced and consumed in the marginal urban settlements of the city of Kimberley in the Northern Cape Province of South Africa. The survey study revealed that traditional beer is no longer being brewed for traditional purposes only, as was the case in the past, but rather for commercial gain. Both brewers and consumers, however, appeared to be largely unaware of disease-causing micro-organisms present on the hands or bodies of handlers that can be transferred to the beverage during the handling process, and were seemingly not conversant with regard to the effects of hazardous ingredients sometimes incorporated during the brewing process. Unemployment and a lack of education emerged as pivotal factors related to the production of traditional beer and the ignorance of the associated safety thereof. The survey further indicated that although facilities such as the availability of potable water (taps in yards) and flushing toilets were sometimes in place, other facilities such as basins with hot running water were often not available. In commercially produced and homebrewed traditional beer the mean counts for total coliforms and Staphylococcus spp. were circa 105 cfu.ml-1 whereas the TVC (Total Viable Counts) and total fungi counts were 106 and 107 cfu.ml-1 respectively. The total coliforms and Staphylococcus spp. counts for homebrewed traditional beer were approximately one log-phase higher than the commercial version. The counts in the homebrewed beer probably originated from contamination during handling, while in the commercial product contamination originated either in the raw ingredients or during postprocessing and consumption. Apart from staphylococci, considerable numbers of total coliforms indicating faecal contamination were noted. A rapid, easy, reliable and accurate technique that could be used to quantify the level of mycotoxins (deoxynivalenol and citrinin) in the beer was developed through validation of the ELISA Ridascreen methodology. Using this method, the deoxynivalenol (DON) level in the beer samples was found to exceed the recommended levels suggested by the European Union, while citrinin levels in the samples varied between 35.6 ppb and 942.2 ppb. In the case of citrinin there were statistically significant differences between spring, summer and winter samples, confirming the seasonal impact on fungal growth and consequent mycotoxin production. An R2-value of 0.409 was noted between DON and citrinin, indicating a weak positive association. Finally, an awareness programme in the format of a poster with accompanying subscripts was developed to address issues of safety and hygiene of traditional beer in the study area. The poster utilises animatedstyle colour images of selected practices that need to be addressed, accompanied by slogans summarising the particular image in English, Afrikaans and Setswana. It is envisaged that, as part of a comprehensive awareness programme, the poster will contribute greatly to the quality, safety and promotion of traditional beer in the area

The contribution of seasonal climate forecasts to the management of agricultural disaster-risk in South Africa

A thesis submitted to the Faculty of Science, University of the Witwatersrand, Johannesburg, in fulfilment of the requirements for the degree of Doctor of Philosophy. July 2014.South Africa’s climate is highly variable, implying that the national agricultural sector should make provision to have early warning services in place in order to reduce the risks of disasters. More than 70% of natural disasters worldwide are caused by weather and climate or weather and climate related hazards. Reliable Seasonal Climate Forecasting (SCF) for South Africa would have the potential to be of great benefit to users in addressing disaster risk reduction. A disaster is a serious disruption of the functioning of a community or a society, causing widespread human, material, economic or environmental losses, which exceed the ability of the affected community or society to cope when using their own resources. The negative impacts on agricultural production in South Africa due to natural disasters including disasters due to increasing climate variability and climate change are critical to the sector. The hypothesis assumed in the study is the improved early warning service and better SCF dissemination lead to more effective and better decision making for subsequent disaster risk reduction in the agricultural sector. The most important aspect of knowledge management in early warning operations is that of distributing the most useful service to the target group that needs it at the right time. This will not only ensure maximum performance of the entity responsible for issuing the early warnings, but will also ensure the maximum benefit to the target group. South Africa is becoming increasingly vulnerable to natural disasters that are afflicted by localised incidents of seasonal droughts, floods and flash floods that have devastating impacts on agriculture and food security. Such disasters might affect agricultural production decisions, as well as agricultural productivity. Planting dates and plant selection are decisions that depend on reliable and accurate meteorological and climatological knowledge and services for agriculture. Early warning services that could be used to facilitate informed decision making includes advisories on iv future soil moisture conditions in order to determine estimated planting times, on future grazing capacity, on future water availability and on forecasts of the following season’s weather and climate, whenever that is possible. The involvement of government structures, obviously, is also critical in immediate responses and long term interventions. The importance of creating awareness, of offering training workshops on climate knowledge and SCF, and of creating effective early warning services dissemination channels is realized by government. This is essential in order to put effective early warning services in place as a disaster-risk coping tool. Early warning services, however, can only be successful if the end-users are aware of what early warning systems, structures and technologies are in place, and if they are willing that those issuing the early warning services become involved in the decision-making process. Integrated disaster-risk reduction initiatives in government programmes, effective dissemination structures, natural resource-management projects and communityparticipation programmes are only a few examples of actions that will contribute to the development of effective early warning services, and the subsequent response to and adoption of the advices/services strategies by the people most affected. The effective distribution of the most useful early warning services to the end-user, who needs it at the right time through the best governing structures, may significantly improve decision making in the agricultural, food security and other water-sensitive sectors. Developed disaster-risk policies for extension and farmers as well as other disaster prone sectors should encourage self-reliance and the sustainable use of natural resources, and will reduce the need for government intervention. The SCF producers (e.g. the South African Weather Service (SAWS)) have issued new knowledge to intermediaries for some years now, and it is important to determine whether this knowledge has been used in services, and if so whether these services were applied effectively in coping with disaster-risks and in disaster v reduction initiatives and programmes. This study for that reason also intends to do an evaluation of the knowledge communication processes between forecasters, and intermediaries at national and provincial government levels. It therefore, aims to assess and evaluate the current knowledge communication structures within the national agricultural sector, seeking to improve disaster-risk reduction through effective early warning services. A boundary organisation is an organization which crosses the boundary between science, politics and end-users as they draw on the interests and knowledge of agencies on both sides to facilitate evidence base and socially beneficial policies and programmes. Reducing uncertainty in SCF is potentially of enormous economic value especially to the rural communities. The potential for climate science to deliver reduction in total SCF uncertainty is associated entirely with the contributions from internal variability and model uncertainty. The understanding of the limitations of the SCFs as a result of uncertainties is very important for decision making and to end-users during planning. Disappointing, however, is that several studies have shown a fairly narrow group of potential users actually receive SCFs, with an even a smaller number that makes use of these forecasts In meeting the objectives of the study the methodology to be followed is based on knowledge communication. For that reason two types of questionnaires were drafted. Open and closed questionnaires comprehensively review the knowledge, understanding, interpretation of SCFs and in early warning services distribution channels. These questionnaires were administered among the SCF producers and intermediaries and results analysed. Lastly the availability of useful SCFs knowledge has important implications for agricultural production and food security. Reliable and accurate climate service, as one of the elements of early warning services, will be discussed since they may be used to improve agricultural practices such as crop diversification, time of planting vi and changes in cultivation practices. It was clear from the conclusions of the study that critical elements of early warning services need to receive focused attention such as the SCF knowledge feedback programme should be improved by both seasonal climate producers and intermediaries, together with established structures through which reliable, accurate and timely early warning services can be disseminated. Also the relevant dissemination channels of SCFs are critical to the success of effective implementation of early warning services including the educating and training of farming communities. The boundary organisation and early warning structures are important in effective implementation of risk reduction measures within the agricultural sector and thus need to be prioritised. Enhancing the understandability and interpretability of SCF knowledge by intermediaries will assist in improving action needed to respond to SCFs. Multiple media used by both SCF producers and intermediaries in disseminating of SCFs should be accessible by all users and end-users. The Government should ensure that farming communities are educated, trained and well equipped to respond to risks from natural hazards

Seasonal variation of citrinin in traditionally brewed African beer

A seasonal study on citrinin concentrations in traditional beer was conducted using a standardised enzyme-linked immunosorbent assay. Representative samples of indigenous South African beer were collected during the hot, mild and cold seasons from marginal-urban settlements in the Kimberley area, South Africa. The mean temperature and humidity readings were 37C and 29% for respectively summer, 19.4C and 7.1% for spring, and 16.3C and 6.5% for winter. Samples were analysed for the mycotoxincitrinin using a commercial Ridascreen (citrinin) ELISA kit, validated for the purpose of the study. The recovery level achieved for citrinin in beer samples using the kit was 117 + - 15%. The inter-assay and intra-assay variations were 17.8 and 14.8% respectively. Standard curves prepared using traditional beer samples were similar to the standard curves prepared using the kit standards. The mean citrinin concentrations found in the various samples were 257.6 ug/kg, 99.0 and 185.7 ug/kg for the summer, spring and winter seasons respectively and the levels ranged between 35.6 ug/kg (min) and 924.2 ug/kg (max). Statistically significant differences (p ?0.05) were found between the citrinin levels of the summer and spring samples and also between citrinin levels of the spring and winter samples (p ?0.001). The relatively high levels of citrinin in selected samples may, with prolonged exposure, have adverse impacts on the health of consumers. Thus further studies into the origin and levels of this mycotoxin should be a priority

Sensory perception of bitterness and astringency in sorghum

There is a conflict of interest between the sorghum producers, for whom condensed tannins in sorghum have agronomic advantages, and sorghum users for whom condensed tannins in sorghum are perceived as nutritionally harmful and unpalatable. However, in recent years there has been growing interest in food phenolics due to their antioxidant potential. Thus, enhancing the content of phenolic compounds in plant foods through selective breeding and/or genetic improvement is now being viewed as a potent dietary option for disease prevention and control. However, the objectionable sensory attributes (bitterness and astringency) of phenolic compounds, especially condensed tannins, have resulted in low consumption of foods rich in these compounds. This study investigated the sensory attributes of products of sorghums varying in total phenol and condensed tannin content as well as their acceptance. A descriptive sensory panel described the sensory attributes including bitterness and astringency of two products, sorghum rice and bran infusions of six sorghum cultivars: three containing tannins and three with no detectable tannins. The products of all the sorghums (tannin and tannin-free) were perceived to different degrees as both bitter and astringent. The products of sorghums with the highest total phenol and tannin content were most bitter and astringent while those from tannin-free sorghums with the lowest total phenol content were least bitter and astringent. The products of NS 5511 (tannins - 1.8% catechin equivalents CE), were perceived similar in both bitterness and astringency to those of a tannin-free sorghum (PAN 8564). Using the Dual Attribute Time Intensity (DATI) sensory method the descriptive sensory panel determined the intensity and time course of bitterness and astringency of bran infusions of sorghums varying in total phenol and condensed tannin content. The infusion from the sorghum with the highest condensed tannin content (PAN 3860) was perceived as most bitter and most astringent and that from the tannin-free sorghum with the least total phenol content (Phofu) was least bitter and astringent. Bitterness of the sorghum infusions developed and reached maximum intensity significantly faster than astringency. The total duration of the astringency sensation lasted significantly longer than bitterness. The more bitter and more astringent the sorghum was, the longer the persistence of the bitter and astringent after-taste. The infusion of NS 5511 was again perceived similar to tannin-free sorghums in both bitterness and astringency. These findings seem to suggest that there is a condensed tannin threshold level at which the tannins are not ‘strongly’ perceived and thus are not objectionable. A consumer panel classified by 6-n-propylthiouracil (PROP) taster status assessed the colour, texture, flavour and overall liking of sorghum rice of two tannin-containing (tannin) sorghums and two tannin-free sorghums. The sorghum rice from PAN 3860, with the highest tannin content, received significantly lower acceptance ratings for all the sensory attributes than the other sorghums. With the exception of appearance, the acceptance of the sorghum rice from the tannin sorghum NS 5511 was not significantly different from that of the two tannin-free sorghums. The PROP tasters (medium and super) could distinguish differences among the sorghum cultivars varying in tannin content levels which presumably led to the significant difference in their acceptance ratings for the most bitter and astringent sorghum compared to others. On the other hand the non tasters preferred the cultivars equally, presumably because they could not detect taste differences (in bitterness and astringency) between the sorghum cultivars. The results of the consumer panel confirm the predictions made from the descriptive sensory panel results that not all the tannin sorghum products would be objectionable to consumers. It is proposed that the condensed tannin threshold level is 2.0% CE inclusive of the tannin content level of NS 5511 (1.8% CE). It is recommended that future breeding programmes investigate production of sorghums like NS 5511 with condensed tannin levels that fall within this threshold limit. The level of condensed tannins in these sorghums would provide the agronomic advantages for the farmer by reducing pre-harvest and post-harvest losses as well as provide the antioxidant benefits associated with them without negatively affecting the nutritional value of the food/feed. Since the negative sensory properties of these sorghums are not strongly perceived they would not be objectionable to consumers, thus making them a promising health option for millions of people.Thesis (PhD)--University of Pretoria, 2009.Food Scienceunrestricte

Sorghum as a household food and livelihood security crop under climate change in South Africa: A review

Extreme events, declining rainfall and increasing temperatures under climate change threaten smallholder households’ food and livelihoods security. The potential of sorghum (Sorghum bicolor [L.] Moench) to contribute to food security and livelihoods of smallholders in South Africa has not been realised, despite its resilience to heat and drought, due to its marginalisation in research, breeding, the scale of production, and policy support. Consequently, to reduce vulnerability and boost sorghum’s position as a key climate change adaptation crop, in this review we examined some biophysical, socio-economic, socio-cultural and institutional barriers that constrain its production and performance on smallholder farms in South Africa. We further suggest pertinent issues to be addressed to improve production and productivity on smallholder farms. Increasing awareness, policy development and support, and capacitation of extension services, as well as improving market access, agronomic and cultural practices, and availability of more locally adapted sorghum varieties are requisite factors in addressing the prevailing constraints limiting sorghum production. Furthermore, tailored and site-specific studies at farm and landscape level are imperative for informed management and decision support. Thus, an integrated and multidisciplinary approach is key in fostering significant improvement in sorghum production and performance in smallholder systems in South Africa to reduce climate change vulnerability. Significance: Sorghum has the potential to bolster food and livelihoods of smallholder farmers in South Africa. Socio-economic, socio-cultural and biophysical challenges limit sorghum production and performance in South Africa. An integrated and multidisciplinary approach is required to optimise the opportunities to improve sorghum production and performance in South Africa

The effect of lockdown regulations on SARS-CoV-2 infectivity in Gauteng Province, South Africa

Background. On 26 March 2020, the South African (SA) government initiated a 21-day national level 5 lockdown which was subsequently eased off and downgraded to level 4 on 1 May and to level 3 on 1 June. The effect of lockdown measures on SARS-CoV-2 infectivity is currently uncertain. In this article, we analyse the effects of the lockdown measures on the SARS-CoV-2 epidemic in one of the epicentres in SA.Objectives. To measure the effects of lockdown measures introduced in SA on SARS-CoV-2 attack rates (ARs, the percentage of individuals who tested positive in a specified time period) in Gauteng Province during a 4-month period (March - June 2020).Methods. In this retrospective cohort study, we used a comprehensive database from an independent pathology laboratory in Gauteng. We analysed trends of positivity rates of reverse transcription polymerase chain reaction tests done during the 4-month period. The ARs are reported over time (unweighted and age-weighted 14-day moving averages) by age groups, gender, and different regions/districts in Gauteng.Results. A total of 162 528 tests were performed at a private laboratory between 5 March and 30 June 2020, of which 20 574 were positive (overall AR 12.7%). These positive tests constituted 44.8% of all positive cases in the province (20 574/45 944). Sixty-two percent of all tests were done in June during lockdown level 3. There was an exponential increase in the AR in June (18.3%) when lockdown was eased to level 3, in comparison with 4.2% (March), 2.2% (April) and 3.3% (May). The increase in June was seen in all the age groups, although it was more pronounced in the 21 - 60 years age groups than the younger (0 - 20 years) and older (>60 years) age groups. The AR was significantly higher in males (13.2%) compared with females (12.1%) (χ2 test, p<0.0001).Conclusions. The findings of this study testify to the rapid increase in ARs resulting from easing of the lockdown regulations, especially to level 3 in June. Of concern is the upward trend in the AR across all age groups, especially <20 years (15.9%), which was not reported in other parts of the world. Population age dynamics should therefore be considered when taking future decisions about lockdown regulations

Application of the dual attribute time-intensity (DATI) sensory method to the temporal measurement of bitterness and astringency in sorghum

Bitterness and astringency are attributes generally cited as the cause of tannin sorghums being unpalatable. The objective here was to determine the effect of sorghums with varying tannin content on bitterness and astringency simultaneously using dual attribute time-intensity (DATI). A trained panel assessed bitterness and astringency of bran infusions of tannin and tannin-free sorghums. In both sorghum types, bitterness developed and reached maximum intensity faster (Tmax 22.5 s; P < 0.001) than astringency (27.9 s). The duration of the astringent sensation (Dtot 69.9 s) lasted longer than bitterness (66.3 s). Overall, the temporal parameters for bitterness distinguished infusions from tannin and tannin-free sorghums slightly more clearly than those for astringency. The research established that, for sorghum, bitterness and astringency are related. The DATI method also revealed that panellists’ perceptions of the time course of bitterness and astringency differ.The South African National Research Foundationhttp://onlinelibrary.wiley.co

The effect of lockdown regulations on SARS-CoV-2 infectivity in Gauteng Province, South Africa

BACKGROUND. On 26 March 2020, the South African (SA) government initiated a 21-day national level 5 lockdown which was subsequently eased off and downgraded to level 4 on 1 May and to level 3 on 1 June. The effect of lockdown measures on SARS-CoV-2 infectivity is currently uncertain. In this article, we analyse the effects of the lockdown measures on the SARS-CoV-2 epidemic in one of the epicentres in SA. OBJECTIVES. To measure the effects of lockdown measures introduced in SA on SARS-CoV-2 attack rates (ARs, the percentage of individuals who tested positive in a specified time period) in Gauteng Province during a 4-month period (March - June 2020). METHODS. In this retrospective cohort study, we used a comprehensive database from an independent pathology laboratory in Gauteng. We analysed trends of positivity rates of reverse transcription polymerase chain reaction tests done during the 4-month period. The ARs are reported over time (unweighted and age-weighted 14-day moving averages) by age groups, gender, and different regions/districts in Gauteng. RESULTS. A total of 162 528 tests were performed at a private laboratory between 5 March and 30 June 2020, of which 20 574 were positive (overall AR 12.7%). These positive tests constituted 44.8% of all positive cases in the province (20 574/45 944). Sixty-two percent of all tests were done in June during lockdown level 3. There was an exponential increase in the AR in June (18.3%) when lockdown was eased to level 3, in comparison with 4.2% (March), 2.2% (April) and 3.3% (May). The increase in June was seen in all the age groups, although it was more pronounced in the 21 - 60 years age groups than the younger (0 - 20 years) and older (>60 years) age groups. The AR was significantly higher in males (13.2%) compared with females (12.1%) (χ2 test, p<0.0001). CONCLUSIONS. The findings of this study testify to the rapid increase in ARs resulting from easing of the lockdown regulations, especially to level 3 in June. Of concern is the upward trend in the AR across all age groups, especially <20 years (15.9%), which was not reported in other parts of the world. Population age dynamics should therefore be considered when taking future decisions about lockdown regulations.http://www.samj.org.zaam2021School of Health Systems and Public Health (SHSPH

Estimated SARS-CoV-2 infection rate and fatality risk in Gauteng Province, South Africa : a population-based seroepidemiological survey

DATA AVAILABILITY : De-identified individual-level data and data sets generated during the current study are available for researchers who provide a methodologically sound proposal. If approved, the requestor must sign a data-use agreement. Additionally, the study protocol is available on request. All requests must be addressed to the corresponding author. Data will be available 3 months after publication of this manuscript.BACKGROUND : Limitations in laboratory testing capacity undermine the ability to quantify the overall burden of severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) infection. METHODS : We undertook a population-based serosurvey for SARS-CoV-2 infection in 26 subdistricts, Gauteng Province (population 15.9 million), South Africa, to estimate SARS-CoV-2 infection, infection fatality rate (IFR) triangulating seroprevalence, recorded COVID-19 deaths and excess-mortality data. We employed three-stage random household sampling with a selection probability proportional to the subdistrict size, stratifying the subdistrict census-sampling frame by housing type and then selecting households from selected clusters. The survey started on 4 November 2020, 8 weeks after the end of the first wave (SARS-CoV-2 nucleic acid amplification test positivity had declined to <10% for the first wave) and coincided with the peak of the second wave. The last sampling was performed on 22 January 2021, which was 9 weeks after the SARS-CoV-2 resurgence. Serum SARS-CoV-2 receptor-binding domain (RBD) immunoglobulin-G (IgG) was measured using a quantitative assay on the Luminex platform. RESULTS : From 6332 individuals in 3453 households, the overall RBD IgG seroprevalence was 19.1% [95% confidence interval (CI): 18.1–20.1%] and similar in children and adults. The seroprevalence varied from 5.5% to 43.2% across subdistricts. Conservatively, there were 2 897 120 (95% CI: 2 743 907–3 056 866) SARS-CoV-2 infections, yielding an infection rate of 19 090 per 100 000 until 9 January 2021, when 330 336 COVID-19 cases were recorded. The estimated IFR using recorded COVID-19 deaths (n = 8198) was 0.28% (95% CI: 0.27–0.30) and 0.67% (95% CI: 0.64–0.71) assuming 90% of modelled natural excess deaths were due to COVID-19 (n = 21 582). Notably, 53.8% (65/122) of individuals with previous self-reported confirmed SARS-CoV-2 infection were RBD IgG seronegative. CONCLUSIONS : The calculated number of SARS-CoV-2 infections was 7.8-fold greater than the recorded COVID-19 cases. The calculated SARS-CoV-2 IFR varied 2.39-fold when calculated using reported COVID-19 deaths (0.28%) compared with excess-mortality-derived COVID-19-attributable deaths (0.67%). Waning RBD IgG may have inadvertently underestimated the number of SARS-CoV-2 infections and conversely overestimated the mortality risk. Epidemic preparedness and response planning for future COVID-19 waves will need to consider the true magnitude of infections, paying close attention to excess-mortality trends rather than absolute reported COVID-19 deaths.The Bill and Melinda Gates Foundation.https://academic.oup.com/ijehj2023Family Medicin

Nosocomial Outbreak of Novel Arenavirus Infection, Southern Africa

This case reinforces the need for strict screening of internationally transferred patients