Hassan Al-Demerdash
Suez Canal University
Egypt
Title: Detection of Bacterial Pathogens in Some Milk Products and Baby Foods Using A Specific PCR Assay
Biography
Biography: Hassan Al-Demerdash
Abstract
The present investigation studied the effects of some date palm (date-paste) and olive oil on the viability of probiotic starter culture (Lactobacillus acidophilus and Bifidobacterium breve) in fermented milk during manufacture and storage period. Date-paste and olive oil were added to fermented milk at different concentrations (based on a previous sensory analysis) as follows; 1, 1.5 and 2% for date-paste and 0.5, 1.5, 2.5% for olive oil respectively. Changes in chemical and viable total bacterial count of fermented milk were monitored during manufacture and storage at 4° C for 30 days. Data showed that the incubation time that was needed to reach pH 4.5 was considerably affected by the added ingredients. Also, the drop in pH or the increase in acidity of this fermented milk was dependent on the added ingredients and the percentage of supplementation. Results indicated that addition of date-paste and olive oil improved the viability of probiotic starter culture and the microbiological properties in the treated samples in comparison with control; the survival of probiotic bacteria in all treatments which were in viable counts remained at >107 cfu/g after 30 days of storage at 4° C. Moreover, addition of date palm-paste improved the viablity and stabilty of probiotic starter culutre than olive oil especially at the end of storage and the total viable counts were 7.1, 7.4, 7.7 and 7.5, 8.0 and 8.1×10-7 for olive oil and dates-paste at the end of storge, respectively. No clear difference was observed between the treatments in the effect on the fermented milk characteristics compared to the control one. Supplementation of the fermented milk with 2% date-paste and 1.5% olive oil improved the rheological properties and reduced the curd syneresis rate. Sensory evaluation showed that fermented milk fortified with 2% date-paste and 1.5% olive oil recorded the highest score and overall acceptability than the other treatments. It is suggested that the fermented milk of acceptable quality and high total probiotic bacterial count during storage can be made from milk supplemented with adjusted concentration (wt/vol) from date-paste and olive oil.