Date fruits extract was assessed as substrate for pristinamycin production in shake flasks using Streptomyces pristinaespiralis DSMZ 40338 as production organism. A process of microfiltration, concentration, and solvent extraction was used to recover the antibiotic from the fermentation broth and its antimicrobial activity was tested using a well assay method. During a fermentation period of 120 h, the bacterium consumed approximately 28.4 g/l sugars, grew from 0.4 g/l to 4.0 g/l dry weight, and produced 51.0 mg/L pristinamycin. The microfiltration, concentration, and ethyl acetate solvent extraction applied resulted in 71% pristinamycin recovery. The antibiotic showed inhibition capacity comparable to that of the pristinamycins IA and IIA standards. The inhibited bacteria were Staphylococcus aureus, Escherichia coli, and Enterococcus faecium. Clear inhibition zones of 13.3-19.6 mm diameter were formed.
Changes in crude protein, soluble sugars and organic acids during traditional Kisra bread preparation from three sorghum varieties were investigated. Fermented dough was prepared in the traditional way used by Sudanese housewives. For the three varieties the protein content was not significantly increased during the fermentation. Traditional fermentation caused decrease in soluble sugars content, whereas the main by-products of the fermentation, lactic acid, acetic acid and ethanol increased. The pattern of change in the level of soluble sugars of the three sorghum varieties were similar. During the first 4 h of fermentation, glucose concentration increased by 259, 102 and 73% for Fetarita, Safra and Ahmer variety, respectively. Thereafter it started to decrease at a steady rate towards the end of the fermentation process. The fructose concentration was decreased and completely utilized after 12, 16 and 20 hours for Safra, Ahmer and Fetarita varieties, respectively. Sucrose in three varieties was completely utilized after 4 hours, while maltose was completely utilized after 8 h. Lactic acid production started from the beginning of fermentation to the end, while production of acetic acid and ethanol started after 4 hours of fermentation and continued to increase at slow rate. Fetarita variety had the least amount of lactic acid, acetic acid and ethanol, while there was no variation between Safra and Ahmer variety.
The effect of treating date fruits with electrolyzed oxidizing water for 5, 15 and 30 min on the general microbial contamination and on the added contamination with Staphylococcus aureus, Pseudomonas aeruginosa, Escherichia coli and Aspergillus fumigates was investigated. Soaking for 15 min was found enough for the reduction of general contamination with mesophilic aerobic bacteria, coliforms, molds and yeasts to levels that meet the requirements of Saudi Standards. The treatment was also found as the most effective for the reduction of added contamination with S. aureus, P. aeruginosa, E. coli and A. fumigates. Synthesis normal microbial contamination of date fruits can be successfully controlled by treatment with electrolyzed oxidizing water.
A thermotolerant strain of the yeast Kluyveromyces marxianus, isolated from Kenana sugar factory in the Sudan, was used for the production of ethanol from molasses. Fermentations were carried out in a bioreactor with 10-litre working volume at three temperatures and three sugar concentrations in batch and at one temperature and three feeding rates in fed-batch processes. In the batch fermentations, the best results were obtained at 40°C and 20% sugar, where a maximum of 9.2% (w/v) ethanol concentration was produced in 30 hours with a yield of 90% of the theoretical and a maximum ethanol specific productivity of 0.65 g per gramme yeast and hour. In the fed-batch process at 40°C, the best results were obtained at 0.5 l/h feeding rate of a substrate with 400 g/l sugar. Under such conditions, the yeast produced up to 9.34% (w/v) ethanol with 91.6% of the theoretical yield in 14 hours of fermentation and a maximum specific ethanol productivity of 0.9 g per gramme yeast and hour.
Enterobacteriaceae can contaminate meat during various stages of processing, including slaughter, evisceration, and butchering, causing foodborne illnesses. The purpose of the study was to investigate the prevalence of Enterobacteriaceae associated with carcasses obtained from slaughterhouses and raw cut meat collected from butcher shops. A total of 120 samples of camels and cattle were identified using biochemistry and PCR testing. Total viable count (TVC) was range from 4.91 to 5.37 Log10 CFU/g in slaughterhouses and butcher shops. E. coli was predominating with 84 (70%) among all samples, where the camels had the highest with 100% and sheep the lowest with 30%. Salmonella spp. was confirmed in 40% of camel samples, 47.5% of cattle samples, and 32.5% in sheep samples. Twenty-five Enterobacteriaceae genera were confirmed using PCR. Where sheep’s samples had the highest occurrence of Enterobacteriaceae with 15 different genera followed by camels and cattle samples with 14 different genera. The prevalence of Enterobacteriaceae among camel, cattle, and sheep carcasses raises significant concerns regarding food safety. Adherence to good hygiene practices throughout animal slaughtering is crucial to minimize the risk of infection and transmission and ensure food safety.
