| Autor: |
Abdullaeva, Asiat M., Blinkova, Larisa P., Pakhomov, Yury D., Valitova, Rumiya K., Orlova, Valentina S., Karachina, Tatiana A., Ambrazheevich, Yuliya V. |
| Předmět: |
|
| Zdroj: |
Journal of Hygienic Engineering & Design; 2022, Vol. 38, p58-64, 7p |
| Abstrakt: |
The problem of viable but non-culturable (VBNC) bacteria is important for food industry, because their presence in foods cannot be detected using conventional methods. These dormant microbes pose a health threat because they can return to active state and cause a disease outbreak. Off-the-shelf chicken mince was used as a model substrate for detection of VBNC cells. 5 grams this mince were suspended in 5 mL sterile normal saline solution. The mixture was immediately plated on nutrient agar for determination of CFU/mL value. Total number of cells in the suspension was determined using a counting chamber, and portion of viable cells was determined using Live/Dead® kit of DNA-binding dyes. Another sample of chicken mince was artificially contaminated with Staphylococcus aureus 209P by combining 5 grams of meat with 5 mL of 18-hour broth culture. The mixture contained 1.136 ± 0.13 x109 cells/g. The same testing procedures were performed as for the first sample. Subsequent to determination of viability parameters, both contaminated and uncontaminated samples were incubated for 5 hours at room temperature, and measuring procedures were repeated. Initial value for non-contaminated chicken mince was (4 ± 0.44 x 10³ CFU/mL. Direct counting in a microscope showed that total cell count was 6 orders of magnitude higher than CFU/mL, and cells were 99.99% VBNC. During 5 hours of incubation at 21 ± 1 °C total number of cells/mL and portion of VBNC cells didn't change significantly, but CFU/g increased to 9 ± 9.9 x 104. In the sample contaminated with S. aureus were revealed 3 ± 0.32 x 105 CFU/g. Though, 99% of cell population was viable, and 97.33% of cells were VBNC. After 5h incubation of samples CFU/g decreased to 8 ± 0.87 x 10³. However, viability and culturability remained relatively unchanged. Therefore, number of VBNC cells increased to 99.99% over incubation period. Thus, we showed for the first time that VBNC cells are present in chicken mince and can multiply to dangerous level. [ABSTRACT FROM AUTHOR] |
| Databáze: |
Complementary Index |
| Externí odkaz: |
|
