Rania Al-Groom

Department of Allied Medical Sciences, Zarqa University College, Al Balqa Applied University- Jordan.


This study was carried out to investigate the microbiological quality of cheddar cheese collected from markets and restaurants. A total of one hundred and fifty cheddar cheese samples were collected randomly in accordance with standard protocols from different markets and restaurants in Amman- Jordan.  Pathogenic bacteria which include Salmonella, coliform bacteria, Staphylococcus aureus, and Listeria monocytogenes were considered as indicators of microbiological quality. All tests were performed according to official documented procedures. Listeria monocytogenes was found in 4% of market pre-sliced cheese and 8% pre-sliced restaurant samples. Packaged cheese samples that were sliced on request were free from Listeria monocytogenes. About 12% of pre-sliced restaurant cheese samples and about 8% of pre-sliced market samples were contaminated with S. aureus compared with only 4% of sliced on request cheese samples. Salmonella was not detected in packaged cheddar cheese that was sliced on request. However, about 10% of sliced cheddar cheese market samples and 8% of sliced cheddar cheese samples collected from restaurants were contaminated by Salmonella. About 10% of pre sliced market samples were polluted by coliform  compared with 2% sliced on request cheddar cheese. The highest percentage of contaminated cheddar cheese by coliform was detected in restaurant samples (14%). The Jordanian food standards states that cheddar cheese samples must be free from pathogenic bacteria indicated above, therefore, a percentage of samples investigated herein are out of specifications. It is evident from the results presented above that the prevalence of different pathogenic organisms in the cheese samples studied was limited but mostly due to unhygienic handling of the product prior to presentation to the end customer.

Keywords: Cheddar cheese, Contamination, Salmonella, Coliform, Staphylococcus, and L. monocytogenes.