A review of foodborne diseases outbreaks reported to the outbreak response unit, national institute for communicable diseases, South Africa, 2013–2017

Food handlers' knowledge, attitudes and self-reported practices regarding safe food handling in charitable food assistance programmes in the eThekwini District, South Africa: cross-sectional study

OBJECTIVE

This study aimed to assess food handlers' knowledge, attitudes and self-reported practices towards safer donated foods.

DESIGN

This cross-sectional study was conducted from January to May 2021.

SETTING

This study was conducted in the eThekwini District, South Africa.

PARTICIPANTS

A convenience sampling-based cross-sectional survey of food handlers (n=252) served as the study's main source of data. A total of eight study sites across five municipal planning regions of eThekwini District were visited. The principal investigator administered the validated structured standardised questionnaire, using participants' language of choice, which was either English or isiZulu. All the questions in the questionnaire were asked in exactly the same manner, following the same flow, in order to avoid bias and ensure consistency. Furthermore, the close-ended nature of questions in the questionnaire mitigated the risks of question manipulation. The questionnaire was adapted from the WHO's five keys to a safer food manual.

PRIMARY AND SECONDARY OUTCOME MEASURES

The primary outcome was the knowledge, attitudes and self-reported practices towards safer donated foods. The secondary outcomes were the sanitary conditions of infrastructure and facilities, food handlers' observed food handling behaviour and nutritional information/labelling.

RESULTS

The results show that the food handlers had good knowledge, positive attitude and acceptable behaviours towards safe food handling and general hygiene, with mean scores (SD) of 62.8 (14.6), 92.5 (14.1) and 80.4 (13.3), respectively. Significant correlations were found between knowledge and attitudes (p=0001), knowledge and practices (p<0001), and attitudes and practices (p=0.02). However, the correlations between knowledge versus attitude and attitude versus practice were poor (Spearman's r<0.3), and the association between knowledge versus practice was moderate (0.3-0.7). The majority of food handlers (92.5%) did not understand the value of thorough cooking and temperature control. About 53% of respondents acknowledged to never adequately reheating cooked meals, 5% did not see the significance of preventing cross-contamination and 5% were unsure.

CONCLUSIONS

Despite the relatively positive knowledge, attitude and practice levels of the food handlers, safe food handling and hygiene practices, such as thorough cooking and temperature control, properly reheating cooked meals and taking precautions to prevent cross-contamination, require some emphasis.

Progress in Fluorescence Biosensing and Food Safety towards Point-of-Detection (PoD) System

The detection of pathogens in food substances is of crucial concern for public health and for the safety of the natural environment. Nanomaterials, with their high sensitivity and selectivity have an edge over conventional organic dyes in fluorescent-based detection methods. Advances in microfluidic technology in biosensors have taken place to meet the user criteria of sensitive, inexpensive, user-friendly, and quick detection. In this review, we have summarized the use of fluorescence-based nanomaterials and the latest research approaches towards integrated biosensors, including microsystems containing fluorescence-based detection, various model systems with nano materials, DNA probes, and antibodies. Paper-based lateral-flow test strips and microchips as well as the most-used trapping components are also reviewed, and the possibility of their performance in portable devices evaluated. We also present a current market-available portable system which was developed for food screening and highlight the future direction for the development of fluorescence-based systems for on-site detection and stratification of common foodborne pathogens.

A SWOT analysis of contemporary gaps and a possible diagnostic tool for environmental health in an upper-middle income country: a case study of South Africa

This study evaluated the state of environmental health in the Republic of South Africa using the strengths, weaknesses, opportunities, and threats (SWOT) analysis framework. The internal and external factor evaluations were conducted by reviewing existing literature searched using a combination of keywords and boolean functions. The weighted score for the strengths and weaknesses was 0.79 and 1.04, respectively. The external factor evaluations findings revealed that environmental health has an equal amount of threats and opportunities, however, the threats outweigh the opportunities. The total weighted score for the internal and external factor evaluations was 1.83 and 2.25, respectively, which were below the average value of 2.5. The internal-external factors matrix indicated that environmental health in the Republic of South Africa needs to be refocused and re-aligned to public health protection. Failure to address the weaknesses and threats and optimise the strengths and opportunities may further weaken the provision of environmental health services.

Assessment of the molecular epidemiology and genetic multiplicity of Listeria monocytogenes recovered from ready-to-eat foods following the South African listeriosis outbreak

Following the recent listeriosis outbreak in South Africa, this study was carried out to assess the safety level of various common ready-to-eat foods (RTE) obtained from supermarkets and grocery stores in major towns and cities within the Amathole, Chris Hani and Sarah Baartman Districts Municipalities, Eastern Cape Province, South Africa. A sum of 239 food samples was collected from these locations, and Listeria monocytogenes (Lm) was isolated in line with the recommended techniques by the International Organization for Standardization EN ISO 11290:2017 parts 1 and 2. Identification of the pathogen and detection of various associated virulence genes was done using Polymerase Chain Reaction (PCR) techniques. From the RTE food samples processed, Lm was detected in 107 (44.77%) of the samples. Russian sausage was the most contaminated (78.57%), followed by sliced polony (61.90%), muffins (58.33%), polony (52.63%), and pies (52.38%), while all vetkoek samples examined were negative for Lm. Although the prevalence of Lm in the food samples was very high, concentrations were generally < 100 CFU/g. Strains of Lm recovered from the RTE foods were predominantly epidemiological strains belonging to serotypes 1/2a, 1/2b and 4b. The prevalence of 10 virulence genes including the inlA, InlC, inlJ, plcA, hlyA, plcB, prfA, mpl, inlB, and actA were detected among Lm isolates. Most of the isolates (69.07%) demonstrated the potential for biofilm formation and were categorized as weak (14.95%), moderate (13.40%) and strong (40.72) biofilm formers. Furthermore, molecular typing revealed high levels of genetic diversity among Lm isolates. The findings of this investigation suggested that the presence of Lm in the RTE foods may constitute potential threats to the food sector and could pose public health hazards to consumers, particularly the high-risk group of the population. We, therefore, recommend that adequate food monitoring for safety and proper regulation enforcement in the food sector must be ensured to avoid any future listeriosis outbreak that could be linked to RTE foods in South Africa.

Molecular Detection of Integrons, Colistin and β-lactamase Resistant Genes in Salmonella enterica Serovars Enteritidis and Typhimurium Isolated from Chickens and Rats Inhabiting Poultry Farms

The rapid growth of multidrug-resistant Salmonella is a global public health concern. The aim of this study was to detect integrons, colistin and β-lactamase resistance genes in Salmonella enteritidis and typhimurium. A total of 63 isolates of S. enteritidis (n = 18) and S. typhimurium (n = 45) from fecal samples of layers and rats at chicken farms were screened for antibiotic resistant genes. Conventional PCR was performed for the detection of integrons (classes 1, 2, and 3), colistin (mcr-1-5) and β-lactamase (bla_CTX-M, bla_CTX-M-1, bla_CTX-M-2, bla_CTX-M-9, bla_CTX-M-15, bla_TEM, bla_SHV, and bla_OXA) resistant genes. Of these isolates, 77% and 27% of S. typhimurium and S. enteritidis harboured the mcr-4 encoded gene for colistin, respectively. The prevalence of class 1 integrons for S. typhimurium and S. enteritidis was 100% for each serovar, while for class 2 integrons of S. typhimurium and S. enteritidis it was 49% and 33% respectively, while class 3 integron genes was not detected. Our study also detected high levels of β-lactamase encoding genes (bla gene), namely bla_CTX-M, bla_CTX-M-1, bla_CTX-M-9 and bla_TEM from both S. typhimurium and S. enteritidis. This, to our knowledge, is the first report of mcr-4 resistance gene detection in Salmonella serovars in South Africa. This study also highlights the importance of controlling rats at poultry farms in order to reduce the risk of transmission of antibiotic resistance to chickens and eventually to humans.

Hygienic Food Handling Practices and Associated Factors Among Food Handlers in Ethiopia: A Systematic Review and Meta-Analysis

BACKGROUND

The food handling practices of food handlers can have a significant impact on the hygienic status of the food. The aim of this study was to determine the prevalence and factors associated with hygienic food handling practices among food handlers in Ethiopia.

METHODS

PubMed, Science Direct, Google Scholar, and the Cochrane Library databases were used to find articles. Only cross-sectional studies that met the criteria for inclusion were considered. STATA version 16 statistical software was used to perform the meta-analysis. The study's heterogeneity was determined using Cochrane Q test statistics and the I ² test. A random effect model was used to calculate the pooled prevalence of hygienic food handling practices.

RESULTS

To estimate the pooled prevalence of hygienic food handling practices in Ethiopia, 9 out of 33 reviewed studies were included. The prevalence of hygienic food handling practices was found to be 48.36% (95% CI: 39.74-56.99) in this study. Factors associated with hygienic food handling practices included; lack of food safety training (OR = 5.38; 95% CI: 1.71, 16.89), negative attitude (OR = 3.28; 95% CI: 1.50, 7.13), lack of access to handwashing facilities (OR = 4.84; 95% CI: 1.72, 13.65), lack of regular medical checkup (OR = 5.37; 95% CI: 3.13, 9.23), and lack of secondary education (OR = 2.51; 95% CI: 1.46, 4.32) among food handlers.

CONCLUSION

In this study, the prevalence of hygienic food handling practices among Ethiopian food handlers was significantly low. Unhygienic food handling practices were attributed to a lack of food safety training, regular medical checkups, handwashing facilities, an unfavorable attitude toward food hygiene practices, and a lack of formal education. As a result, food handlers should receive ongoing food safety and hygiene training.

Magnetic Separation and Centri-Chronoamperometric Detection of Foodborne Bacteria Using Antibiotic-Coated Metallic Nanoparticles

Quality and food safety represent a major stake and growing societal challenge in the world. Bacterial contamination of food and water resources is an element that pushes scientists to develop new means for the rapid and efficient detection and identification of these pathogens. Conventional detection tools are often bulky, laborious, expensive to buy, and, above all, require an analysis time of a few hours to several days. The interest in developing new, simple, rapid, and nonlaborious bacteriological diagnostic methods is therefore increasingly important for scientists, industry, and regulatory bodies. In this study, antibiotic-functionalized metallic nanoparticles were used to isolate and identify the foodborne bacterial strains Bacillus cereus and Shigella flexneri. With this aim, a new diagnostic tool for the rapid detection of foodborne pathogenic bacteria, gold nanoparticle-based centri-chronoamperometry, has been developed. Vancomycin was first stabilized at the surface of gold nanoparticles and then incubated with the bacteria B. cereus or S. flexneri to form the AuNP@vancomycin/bacteria complex. This complex was separated by centrifugation, then treated with hydrochloric acid and placed at the surface of a carbon microelectrode. The gold nanoparticles of the formed complex catalyzed the hydrogen reduction reaction, and the generated current was used as an analytical signal. Our results show the possibility of the simple and rapid detection of the S. flexneri and B. cereus strains at very low numbers of 3 cells/mL and 12 cells/mL, respectively. On the other hand, vancomycin-capped magnetic beads were easily synthesized and then used to separate the bacteria from the culture medium. The results show that vancomycin at the surface of these metallic nanoparticles is able to interact with the bacteria membrane and then used to separate the bacteria and to purify an inoculated medium.

Microbial levels on street foods and food preparation surfaces in Mangaung Metropolitan Municipality

Background

The street food sector has become an important component of the food distribution system in many cities in both developing and industrialised countries, particularly for midday meals. However, certain street food can pose a significant risk to consumers because of microbiological contamination.

Aim

The aim of this study was to determine the microbial levels of street foods and preparation surfaces in Mangaung Metropolitan Municipality.

Setting

The study selected study setting was vending sites close to taxi ranks where prepared meals were accessible to consumers.

Methods

The study was conducted in Mangaung Metropolitan Municipality during the winter season. Samples were collected through convenience sampling from the representative towns Thaba Nchu, Botshabelo and Bloemfontein. Using swabs, surface samples were collected and quantified from selective media. Eight beef samples were also collected; the microbial load on each sample was quantified and identified using a RapID kit.

Results

The surface swabs obtained in Botshabelo (1.1 × 10⁴ cfu/m² – 1.1 × 10⁶ cfu/m²) showed higher microbial counts as compared to those obtained in Bloemfontein (1.1 × 10⁴ cfu/m² – 1.1 × 10⁵ cfu/m²) and Thaba Nchu (1.1 × 10⁴ cfu/m² – 1.1 × 10⁵ cfu/m²). Higher microbial counts were observed on meat samples sampled in Thaba Nchu (50 cfu/g x 10⁵ cfu/g), Bloemfontein (48 cfu/g x 10⁴ cfu/g) and Botshabelo (33 cfu/g x 10⁵ cfu/g) when compared to international microbiological standards. After assessing the microbial levels, Staphylococcus aureus, Escherichia coli, Candida guilliermondii, Corynebacterium jeikeium, Psychrobacter phenylpyruvicus and Peptostreptococcus tetradius were identified.

Conclusion

This study confirmed contamination of surfaces and food served by vendors in Mangaung Metropolitan Municipality. The identified foodborne bacteria could pose a public health problem in each specific locality.

Microbiological quality of beef, mutton, and water from different abattoirs in the Eastern Cape Province, South Africa

Background and Aim:

Abattoir processes from skinning, evisceration, to chilling usually lead to meat contamination by foodborne pathogens. Hence, continual microbial surveillance of slaughter carcasses by veterinary public health officials is key to preventing contamination and outbreak of meat-related foodborne diseases. This study was conducted to determine the Enterobacteriaceae count and aerobic plate count (APC) and to detect Escherichia coli and Salmonella spp. in meat and water from selected slaughter facilities.

Materials and Methods:

Retrospective data (n=100) collected in 2017 by the Provincial Veterinary Department of the Eastern Cape Province from abattoirs and prospective survey data of meat (n=50) collected in 2018 from abattoirs in the Eastern Cape Province were utilized in this study. APC and Enterobacteriaceae were enumerated from the samples. In addition, Salmonella and E. coli were isolated from samples using selective media.

Results:

The APC in both retrospective and prospective studies for all samples ranged between 2 and 4.50 log CFU/cm²; similar counts of 2-4.00 log CFU/cm² were recorded for Enterobacteriaceae. No significant difference (p>0.05) for APC and Enterobacteriaceae count across all meat types was noted. Salmonella and E. coli were detected in 50% of beef. E. coli was not detected from mutton, but Salmonella was found in 66.7%. Moreover, 91.7% of the water samples had E. coli, but none had Salmonella.

Conclusion:

The levels of Enterobacteriaceae and APC observed in meat satisfy regulatory conditions outlined by the Department of Agriculture, Forestry and Fisheries, South Africa and show that meat produced from these abattoirs is of acceptable microbial quality. However, the quality of water used in the abattoirs does not meet the requirements set by the government, and contributes to contamination of meat produced in the abattoirs under study. Therefore, we recommend that sources of water be continuously investigated to eliminate or reduce the risk of contamination of meat processed in the abattoirs.

A systems analysis and conceptual system dynamics model of the livestock-derived food system in South Africa: A tool for policy guidance

Global food production systems are currently under scrutiny, in particular the health, nutrition, and environmental impacts of livestock-derived food (LDF). Despite South Africa's recent socio-economic transformation and increased per-capita LDF consumption, the triple burden of malnutrition persists. Policy responses to such complex problems often fail because of linear thinking with short-term goals. However, a systems approach helps identify root causes, feedback mechanisms, potential unintended consequences, and opportunities for integrated, durable solutions. Participation in the systems-thinking process improves stakeholder understanding and buy-in. Our participatory workshop facilitated the development of a systems map for South African LDF, identifying key system elements, linkages, and nexus points. The latter included climate change, land access and management, livestock management and productivity, farming systems, food safety, policy articulation, agricultural knowledge, and income. Based on these findings, and an overview of related literature, we produced a conceptual system dynamics model of the LDF system. We identified key vari-ables and causal relationships, vicious and virtuous loops, system archetypes, conceptual stock and flows, and links to Sustainable Development Goals. The LDF system is complex and dynamic, with a dominance of commercial enterprises across agriculture and food retail, presenting barriers for small and medium-scale individuals. Other key elements relate to population growth and urbanization, land access, deregulation of international trade, climate change vulnerability, feed production limitations, and food safety. Our work provides a unique reference for policymakers, identifying the need for deep structural change, highlighting the possible unintended consequences, and thereby mitigating the risk of system destabilization.

Detection and Molecular Identification of Salmonella Virulence Genes in Livestock Production Systems in South Africa

Livestock are an important source of protein and food for humans, however opportunistic pathogens such as Salmonella spp. turn livestock into vehicles of foodborne diseases. This study investigated the prevalence of virulence genes in Salmonella spp. isolated from livestock production systems in two provinces of South Africa. During the period from May to August, 2018, a total of 361 faecal (189), oral (100), environmental (soil (36) and water (27)) and feed (9) samples were randomly collected from different animals (cattle, sheep, goats, pigs, ducks and chickens) that were housed in small-scale livestock production systems from Eastern Cape and KwaZulu-Natal Provinces in South Africa. Salmonella spp. were isolated and identified using microbiological and DNA molecular methods. Salmonella spp. were present in 29.0% of the samples of which 30.2% belonged to the Salmonella enterica species as confirmed by the positive amplification of the species specific iroB gene. Virulence genes that were screened from livestock-associated Salmonella were invA, iroB, spiC, pipD and int1. Statistically significant associations (p < 0.05) were established between the virulence genes, sampling location, animal host as well as the season when samples were collected. Furthermore, statistically significant (p < 0.05) positive correlations were observed between most of the virulence genes investigated. This is one of the recent studies to detect and investigate livestock-associated Salmonella spp. in South Africa. This study highlights the importance of continuous monitoring and surveillance for pathogenic salmonellae. It also demonstrated the detection and prevalence of virulent Salmonella spp. harbored by livestock in South Africa. This study demonstrated the potential risks of pathogenic Salmonella enterica to cause foodborne diseases and zoonotic infections from farm-to-fork continuum using the global one-health approach.