RESUMO
Objective: The study was designed to show the effect of adding different levels of dried fruit extracts for 14 days on sensory and chemical parameters in dairy drinks. The survival of Pseudomonas aeruginosa and Bacillus cereus in artificially contaminated dairy drinks fortified with these extracts was also studied. Materials and Methods: The freshly watery extracts and nonaqueous extracts of dried fruits were prepared by rotary evaporators and solvents, respectively. The determination of the minimum inhibitory concentration of dried fruit extracts was achieved using the disc diffusion test. The sensory evaluation of samples was done, while the chemical parameters of the examined samples were determined by the calibrated analyzer. In addition, the degree of survival of P. aeruginosa and B. cereus in inoculated milk samples was also estimated. Results: In pasteurized and Rayeb milk samples, the water extract of carob and all alcoholic dried fruit extracts had a significant effect on compositional parameters in comparison to control samples. At day 14 of pasteurized milk storage, the watery (20.0%) and alcoholic (10.0%) extracts of carob significantly improved its sensory parameters. Conclusion: Based on the survival results, all utilized dried fruit extracts had a significant inhibitory effect on P. aeruginosa and B. cereus growth in the fortified milk samples at the end of storage. This trial of the survival of these new dairy drinks is the first investigation, particularly in the Middle East. Extracts of utilized dried fruits have prospective functions that enhance dairy drink characteristics.
RESUMO
Objective: This study was designed to show the effect of adding different levels of microbial (lab-produced) and commercial xanthan (CX) for 30 days on the sensory, chemical, and microbiological parameters of mozzarella cheese (MC). Materials and Methods: The production of xanthan was done in Garcia-Ochoa's medium. The sensory evaluation of the examined MC was achieved through a tabulated scorecard. The Gerber method was used for the determination of MC fat%. The mean counts of staphylococci [colony forming unit (CFU)/gm], coliforms (most probable number/gm), fungi (CFU/gm), and mesophilic bacteria (CFU/gm) were estimated in different fortified cheeses. Also, mean counts of Escherichia coli O157 and Staphylococcus aureus in artificially contaminated MC were determined. Results: The microbial xanthan (MX) had a significant (p < 0.05) effect on the sensory parameters of the examined samples with its concentration (0.0007%) after 20 days of storage. The MX (0.0005%) and CX (0.0002%) had a significant effect on moisture, fat in dry matter, and protein percentage of MC throughout the storage period. The high meltability degree of MC was observed in samples with both types of xanthan (0.0002%) at the end of storage. Conclusion: Both types of xanthan at all concentrations had a significant reducing effect on E. coli O157 and S. aureus in all samples from 10 to 30 days of storage. Xanthan has accepted attentiveness and offers beneficial and safe characteristics that improve its adaptability in MC. In the Middle East, this survival trial of E. coli O157 and S. aureus in the MC supplemented by xanthan is considered a scarce exploratory investigation.
