Inhibitory effect of sour orange (Citrus aurantium) juice on Salmonella Typhimurium and Listeria monocytogenes

- The inhibitory effect of sour orange juice was investigated.
- Salmonella Typhimurium and Listeria monocytogenes were used as test microorganisms.
- The effect of concentration, pH, incubation temperature and time were investigated.
- S. Typhimurium has been found to be more resistant to the variable conditions.
- Incubating at low temperature (4 °C) enhanced the survival of test microorganisms.

The sour orange (Citrus aurantium) juice is commonly used as flavoring and acidifying agent for vegetable salads and appetizers in Turkey. It was aimed to determine the survival and growth pattern of Salmonella Typhimurium and Listeria monocytogenes in sour orange juice. Different concentrations of neutralized and un-neutralized juice samples were inoculated with each of the test microorganisms (∼6 log CFU/mL) separately and then incubated at 4 °C and 37 °C for seven days. It was detected both of the test microorganisms could survive and even grow in neutralized juice samples at 37 °C for two days. However, none of them could survive at the end of seventh day of incubation at 37 °C. Low incubation temperature (+4 °C) increased the survival of the tested microorganisms. Also, it was detected that L. monocytogenes were less resistant to the variable conditions than S. Typhimurium. It was concluded that the antimicrobial effect of sour orange juice mainly depends on the low pH value of the product. However, incubation time and temperature are also effective on the survival of the tested pathogens.