The effect of storage temperature and duration on the microbial growth in Sobia : a Saudi Arabian traditional drink

الملخص EN

Sobia is a popular fermented traditional beverage in Saudi Arabia.

None of the previous studies have reported on the microbial content of Sobia, stored under different conditions.

Sobia samples (48) were divided into two equal sets.

The first set was stored at room temperature (RT=25°C), while the second was stored at cold temperature (CT=2-8°C).

All samples were examined for the presence of micro-organisms (MOs), and pH was measured on different days.

Samples of Sobia stored at RT were analyzed on days 0, 1, 2, and 7, while those stored at CT were examined on days 0, 7, and 14.

The presence percentage of each MO in the 24 samples stored at RT at the different four days were, respectively: Lactobacillus spp.

(50%, 83%, 88% and 100%), Candida spp.

(42%, 71%, 79% and 83%), Saccharomyces cerevisiae (17%, 21%, 25% and 25%), and Klebsiella spp.

(63%, 50%, 38% and 25%).

The MOs present at the greatest quantities in the samples stored at CT at the three different days were, respectively: Lactobacillus spp.

(58%, 92%, and 96%), Candida ssp.

(29%, 29%, and 54%), Klebsiella spp.

(71%, 54%, and 46%), and Saccharomyces cerevisiae (17%, 33%, and 33%).

On day 7 of storage, the pH (mean ± SD) fell in the samples stored at RT from baseline values of 4.20±0.80 to 3.28±0.55 (p<0.001), while in CT samples it decreased from baseline reading of 4.20±0.83 to 3.50±0.55 (p<0.001) after 2 weeks of storage.

Sobia, a fermented beverage in Saudi Arabia, may be contaminated with different pathogenic MOs.

Differences in temperature of storage and duration are associated with changes in MO content and Sobia storage in the cold condition can minimize the risk of any potential infection.