Food & Nutrition

Arab Journal of Food & Nutrition
83. Study Some of the Factors Affecting the Shelf Life of Labneh (2005)
JalaI H. Khataibeh\ Jordan University of Science & Technology
Supervisor: Dr. Reyad R. Shaker
Labneh, a concentrated yogurt product routinely consumed in Jordan and some
part of the Middle East. It is produced by removing a proportion of whey from yogurt
until the desired solids are achieved. The product is a white to creamy paste that has a
smooth texture with lactic acid taste. Commercial samples of labneh were stored at
6°C for 15 days, changes in selected physicochemical, microbiological, and sensory
parameters were observed during storage. PH of the labneh decreased while titratable
acidity increased during storage. Counts of total viable bacteria were decreased at
constant logarithmic rate, whereas the total yeasts were increased rapidly during the
first 11 days, then the number decreased. Psychrotrophic yeast counts were stabilized
during the first 4 days of storage then increased slowly till the end of the storage.
Yeasty and sour tastes of labneh were increased throughout the storage period.
Changes in physicochemical parameters correlated well with the counts of total viable
and psychrotrophic yeast. Product failure time was described and monitored by use of
Weibull hazard method while the end of shelf- life was determined at a probability of
failure of 50%. The results indicate that the total yeasts count, yeasty taste and sour
taste can be used to determine the shelf-life of labneh as cut-off points. Experiments
were conducted to investigate the effects of implementing the HACCP system during
production of labneh and addition of different levels of benzoate and sorbate on
maintaining quality of labneh. The microbial findings demonstrate that applying
HACCP system improves labneh quality preservation. The use of different levels of
benzoate and sorbate did not show any significant effect on yeasts growth, However,
the growth of yeasts was delayed at 400 ppm for benzoate and sorbate.
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Volume 11, No. 25, 2011