Process optimisation for enzymatic clarification of indigenous wild watermelon (Citrullus lanatus) juice.

A fundamental step in improving the quality and consumer acceptability of wild watermelon (Citrullus lanatus) is the process of juice clarification. The aim of this research was to investigate the physicochemical properties of crude wild watermelon (Citrullus lanatus) juice and to optimise the processing conditions, incubation time, incubation temperature and enzyme concentration for the enzymatic clarification of the crude juice. Crude wild watermelon juice samples were treated with pectinase enzyme in different concentrations (0.05 to 0.15 w/w%), at different incubation temperatures (30-50 oC) and for different incubation durations (60-180 min). The effects of the different treatments on turbidity, clarity, viscosity, lightness, and brix were determined. The response models adequately predicted turbidity, clarity, and viscosity at R2 > 0.5, but not lightness considering that R2 < 0.5. The model was statistically significant in predicting turbidity (R2 = 0.86), clarity (R2 = 0.81), viscosity (R2 = 0.97) and brix (R2 = 0.94) - but not lightness (R2 = 0.24) at p < 0.05. The enzyme concentration did not significantly affect turbidity, clarity, and lightness, but it did significantly affect brix positively (p < 0.05). Response surface methodology software was used to determine optimal clarification conditions. In conclusion, the optimum conditions for crude watermelon juice clarification were 0.15 w/w% enzyme concentration, 60 min incubation time and 60 oC incubation temperature. The optimum output parameters were 14.18 NTU for turbidity, 0.04 Abs for clarity, 52.30 L* value for lightness, 1.96 cps for viscosity and 3.08% for Brix.

A 16S Next Generation Sequencing Based Molecular and Bioinformatics Pipeline to Identify Processed Meat Products Contamination and Mislabelling.

Processed meat is a target in meat adulteration for economic gain. This study demonstrates a molecular and bioinformatics diagnostic pipeline, utilizing the mitochondrial 16S ribosomal RNA (rRNA) gene, to determine processed meat product mislabeling through Next-Generation Sequencing. Nine pure meat samples were collected and artificially mixed at different ratios to verify the specificity and sensitivity of the pipeline. Processed meat products (n = 155), namely, minced meat, biltong, burger patties, and sausages, were collected across South Africa. Sequencing was performed using the Illumina MiSeq sequencing platform. Each sample had paired-end reads with a length of ±300 bp. Quality control and filtering was performed using BBDuk (version 37.90a). Each sample had an average of 134,000 reads aligned to the mitochondrial genomes using BBMap v37.90. All species in the artificial DNA mixtures were detected. Processed meat samples had reads that mapped to the Bos (90% and above) genus, with traces of reads mapping to Sus and Ovis (2-5%) genus. Sausage samples showed the highest level of contamination with 46% of the samples having mixtures of beef, pork, or mutton in one sample. This method can be used to authenticate meat products, investigate, and manage any form of mislabeling.

The food safety knowledge of street food vendors and the sanitary conditions of their street food vending environment in the Zululand District, South Africa.

This research sought to evaluate the food safety knowledge of street food vendors and the sanitary compliance status of their vending facilities, Zululand District, South Africa. Data collection was done in a face to face interview with respondents in a cross-sectional survey research design. Data was collected from 399 randomly selected street food vendors and 200 randomly selected street food vending facilities. Only a minority of the street food vendors had attended high school (47 %) and the vast majority (77 %) of them had not attended any food safety training courses. Overall, the vast majority (76 %) of the street food vendors had low food safety knowledge and only 14 % of the street food vending sites had high compliance with sanitary conditions. In conclusion, this study demonstrates that most of vending facilities of street food vendors constitute a food safety risk to the consumers. This was primarily due to the possession of inadequate food safety knowledge of street food vendors, non-compliant street food vending infrastructure, and inadequate monitoring and controls by competent authorities. It is recommended that, authorities should implement the food stalls/caravan system in areas with adequate sanitation and use the licensing and permit tool to ensure control and adherence to food safety regulations and street food vendors and health inspectors should be trained on safe food handling principles and practice.

An assessment of the food safety knowledge and attitudes of food handlers in hospitals.

BACKGROUND: The possession of inadequate food safety knowledge (FSK) by food handlers poses a serious threat to food safety in service establishments. The aim of this research was to investigate factors that influenced the FSK and food safety attitudes (FSA) of employees involved in the preparation and/or the serving of food from nine hospitals in the Capricorn District Municipality (CDM) in Limpopo Province, South Africa. METHOD: Up to 210 individuals (18-65 years) who were employed in these hospitals, and who were involved in the preparation and serving of food to patients were purposefully selected. Data collection was by means of an interview using a questionnaire design for this study. The FSK and FSA scores of hospital food handlers were obtained by adding the correct response to FSK or FSA questions. RESULTS: Only 29% of the hospital food handlers have attended a food safety-training course. Many food handlers were not knowledgeable on the correct temperature for handling foods, and on the correct minimum internal cooking temperature for poultry, seafood and egg. Only the minority of food handlers knew that Salmonella is the main foodborne bacteria pathogen mostly associated with poultry products (47.1%) and that food borne bacteria will grow quickly in food at a temperature of 37 °C (38.1%). Hospital food handlers with higher academic qualifications do not possess more FSK than those with lower academic qualifications. 51% of the hospital food handlers possessed a Satisfactory FSK while 10% possessed a Good FSK and 39% possessed an Inadequate FSK. CONCLUSION: More than 60% of the hospital food handlers possesses either Good FSK or Satisfactory FSK. Higher levels of education, experience in food handling and job position did not lead to better FSK outcome. All the hospital food handlers possess at least a Satisfactory FSA. There was a weak positive but significant correlation between the FSK and FSA of hospital food handlers. It is recommended all employees involved in food handlers be subjected to food safety training programmes on a regular basis irrespective of their academic, employment and training details.

Genome Sequences of Bacillus sporothermodurans Strains Isolated from Ultra-High-Temperature Milk.

Here, we report the draft genome sequences of 3 Bacillus sporothermodurans strains isolated from ultra-high-temperature milk products in South Africa and Brazil and the type strain MB 581 (DSM 10599). The genomes will provide valuable information on the molecular dynamics of heat resistance in B sporothermodurans.

Phytochemical Constituents and Antioxidant and Antimicrobial Activity of Selected Plants Used Traditionally as a Source of Food.

Many indigenous plants have also been used as a source of food and medicine in many African rural communities in the past. The study investigated the antimicrobial activity, phytochemical constituent, and antioxidant activity of selected traditional plants used traditionally as a source of food and medicine. The methanol and water extracts of different plant parts were analyzed for phytochemicals using standard phytochemical screening reagents while the broth microdilution assays were used to analyze antimicrobial activities. Alkaloids, phenols, flavonoids, saponins, tannins, and terpenes were found in one or more of the plant extracts, and all the plant extracts demonstrated scavenging activities. The back extracts of Sclerocarya birrea and the leaf extracts of Garcinia livingstonei exhibit the best antioxidant activities, while the water and methanol back extracts of S. birrea and G. livingstonei were the most active against all the tested foodborne bacteria.

Advantages and limitations of potential methods for the analysis of bacteria in milk: a review.

Contamination concerns in the dairy industry are motivated by outbreaks of disease in humans and the inability of thermal processes to eliminate bacteria completely in processed products. HACCP principles are an important tool used in the food industry to identify and control potential food safety hazards in order to meet customer demands and regulatory requirements. Milk testing is of importance to the milk industry regarding quality assurance and monitoring of processed products by researchers, manufacturers and regulatory agencies. Due to the availability of numerous methods used for analysing the microbial quality of milk in literature and differences in priorities of stakeholders, it is sometimes confusing to choose an appropriate method for a particular analysis. The objective of this paper is to review the advantages and disadvantages of selected techniques that can be used in the analysis of bacteria in milk. SSC, HRMA, REP, and RAPD are the top four techniques which are quick and cost-effective and possess adequate discriminatory power for the detection and profiling of bacteria. The following conclusions were arrived at during this review: HRMA, REP and RFLP are the techniques with the most reproducible results, and the techniques with the most discriminatory power are AFLP, PFGE and Raman Spectroscopy.

The effects of wet heat treatment on the structural and chemical components of Bacillus sporothermodurans spores.

The objective of this research was to study the rate of structural damage and survival of Bacillus sporothermodurans spores following treatment at high temperatures by determining the amount of Dipicolinic acid (DPA) and soluble protein leakage over time. A reference strain of B. sporothermodurans (DSM 10599) and a South African strain (UP20A) isolated from UHT milk were used. To determine the survival of spores at 130 degrees C, spores were heated for 4, 8 and 12min. To check the viability of spores plate counts were determined, while structural damage was determined using the Transmission Electron Microscopy. The filtrate of the heated spore suspension was analysed for the amount of DPA and soluble protein release due to heating. The amount of DPA released was quantified by HPLC analysis while the amount of soluble protein released from heated spores was quantified using the Bradford method. The log values of spore counts, released DPA and soluble proteins from triplicate experiments were analysed. The results of this study indicate that the inactivation of B. sporothermodurans spores during wet heat treatment is due to the penetration of hot moisture into the spore which then moistens the spore components, and inactivates enzymes, and because of the high water pressure, vital spore components such as proteins and DPA in solution leak out of the spore. Interestingly a vast majority of heated spores were inactivated before a significant amount of DPA was released. This research is the first to determine the effect of high temperature wet heat treatment on the structure of B. sporothermodurans spores and has given an insight regarding the mechanisms of destruction of B. sporothermodurans spores by wet heat.