The advantage of this method is reliable red color indicators of isolated and typical
Salmonella colonies.
The method of improving the horizontal method of coagulase-positive
staphylococci detection in milk and dairy products differs from other methods by using
the research suspension, which is prepared in the ratio of 1:5 (samples of milk and dairy
products in the amount of 10−11 cm
3
(d) and 50−55 cm
3
of selective medium of
previous concentration (Giolitti-Cantoni broth and Tween 80), followed by incubation
of received suspension for 18±2 hours at the temperature of 35±1 °C. After that the
culture of received suspension in the quantity of 1.0−1,1 cm
3
is inoculated on the
surface of Petri cup, which contains agar medium of the Beard-Parker. Then it is kept
at room temperature (20±2°C) for 10–15 min and incubated at the thermostat at the
temperature of 35±1 °C for 24±1 hours and 48±1 hours to get the typical colonies of
coagulase-positive staphylococci for 24±1 hours in the form of black or grey, shiny
and bulging, 1.0−1.5 mm in diameter (in 48±1 hours – 1.5−2.5 mm in diameter) and
surrounded by clean area, which has opalescence ring in 24±1 hours of incubation.
The method, which is based on improving the horizontal method of coagulase-
positive staphylococci detection in milk and dairy products, which differs by using the
research suspension, which is prepared in the ratio of 1:5 (samples of milk and dairy
products in quantities of 10−11 cm
3
(d) and 50−55 cm
3
selective medium of previous
concentration (Giolitti-Cantoni broth and Tween 80), followed by incubation of
received suspension for 18 ± 2 hours at the temperature of 35 ± 1 °C. After that the
culture of received suspension in the quantity of 1.0−1,1 cm
3
is inoculated on the
surface of Petri cup, which contains agar medium of the Beard-Parker. Then it is kept
at room temperature (20±2°C) for 10–15 min and incubated in the thermostat at the
temperature of 35±1 °C for 24±1 hours and 48±1 hours to get the typical colonies of
coagulase-positive staphylococci for 24±1 hours in the form of black or grey, shiny
and bulging, 1.0−1.5 mm in diameter (in 48±1 hours – 1.5−2.5 mm in diameter) and
surrounded by clean area, which has opalescence ring in 24±1 hours of incubation.
CONCLUSION
The obtained results were steady and reliable, so these indices can be used in
monitoring the safety of milk and dairy products. In addition, the techniques we applied
in our research are simple-to-use, economical and their results give definable quality
indicators.
BIBLIOGRAPHICAL REFERENCES
1. Microbiology of food and animal feed. Horizontal method Listeria
monocytogenes detection and calculation. – Part 1. Detection method (ISO11290-
- 1270 -