EFFECT OF SOME NATURAL PLANTS OILS ON THE GROWTH OF SOME PATHOGENIC BACTERIA
Authors: Albi Alsanussi Ahmed Ali 
Published: November 2020

This study aimed to determine the influence some of essential oils (black seed oil, garlic oil, and thyme oil on the Growth of some Pathogenic Bacteria (psychotropic bacterial, E.coli, Salmonella and Staphylococcus aureus.
The results showed:-

All treatments had positive effect on the bacterial growth; the treatment of black seed was the highest effective when compared with other treatments.
changes of psychrotrophic bacterial count in minced meat treated with essential oils during storage at 4°C for 20 day.

Microorganisms that grow in food at refrigeration temperature have usually been called psychotropic. Many psychotropic bacteria when present in large numbers can cause a variety of off–flavors as well as physical and defects in foods, Psychrophilic bacteria counts in all treatments at zero time were similar, but there is a significant increase in control sample to 107 log CFU/gm. At the end of storage periods (p≥ 0.05) Psychotropic bacteria counts reduced with addition of essential oils compared with control samples.

Changes of E. coli count in minced meat treated with essential oils during storage at 4°C for 20 day.

Although the total bacterial count was used in bacteriological examination to reflect the hygienic quality, however, it is evident that coliform group count is considered of much greater value in assessing its quality. It was found that control sample had significantly (p≥ 0.05) difference the higher counts E. coli when compared to other treatments which formulated with essential oils at levels 0.50 and 0.75 % and 1% at zero time and at end of storage periods. Essential oil of black seeds at level 1%was more active of inhibiting effect against coliform group bacteria, which disappear after 10 days of storage period compared with other essential oils. Also, E. coli group disappeared in most minced meat samples formulated with essential oil at level 1% at 15 and 20 days.

Changes of Salmonella counts in minced meat treated with essential oils during storage at 4°C for 20 day.

Salmonella is now established, as one of the most important causes of food – borne illness at worldwide. It was found that control sample had significant (p≥ 0.05) difference from the higher counts of Salmonella when compared to other treatments which formulated with essential oils at levels 0.50 and 0.75% and 1% at end of
storage periods. Essential oil of black seed at level 1% was more active of inhibiting effect against Salmonella group bacteria, which disappeared after 5 days of storage period compared with other essential oils. Also, it could be noticed that Salmonella group disappeared from most minced beef samples formulated with essential oil at levels 0.75% and 1% after10 and 15days.

Changes of Staphylococcus Aureus counts in minced meat treated with essential oils during storage at 4°C for 20 day:

The results showed that Staphylococcus aureus counts increased in control sample, so the Staphylococcus aureus count at zero time was 3.3 102 CFU/g, but reached to 5.4 103 CFUI /g at the end of storage period.
It could be noticed that Staphylococcus aureus counts were significantly (p≥ 0.05) decreased during storage time in minced meet sample contained essential oil of black seeds at level 0.75% and 1%. Staphylococcus aureus counts in these samples were less than that in control sample. Meanwhile, after storage for 5 days, Staphylococcus aureus disappeared from minced meet samples contained black seeds essential oil at level 1%.