Detection and Control of Viable but Non-Culture Escherichia coli Using Some Selective Sanitizers
Detection and Control of Viable but Non-Culture Escherichia coli Using Some Selective Sanitizers
Naglaa A. El-Taib1*, Asmaa T. Talayea2, Hanan R. Ghanayem3
ABSTRACT
Many pathogens, including Escherichia coli (E. coli), can enter a viable but non-culturable (VBNC) state in response to environmental stress. In this state, bacteria cannot grow on standard media but retain certain features of viable cells, such as cellular integrity, metabolic activity, and virulence. Therefore, this study examined the effect of chlorine and hydrogen peroxide as common chemical sanitizers on inducing E. coli O157 into a VBNC state. The results showed that after 30 minutes of treatment with 200, 100, or 50 ppm chlorine, the numbers of culturable E. coli significance P<0.05 dropped (100%) from 6.93±0.04 log10 CFU/mL to less than 1 CFU/mL (0.0%). However, after 48 hours of resuscitation using sodium pyruvate as nourished media, the VBNC cells in case of used 200, 100 and 50 ppm chlorine were recorded 3.13±0.04, 4.08±0.04, and 4.49±0.02 CFU/mL, respectively. In contrast, application of 0.1, 0.3-, and 3-mM concentrations of hydrogen peroxide for 30 minutes could not induce E. coli o157 into VBNC state but only significancy (P<0.05) decreased the count of viable cells from 6.93±0.04 (100%) to 6.49±0.03 CFU/ml (93.7%),6.04±0.06 CFU/ml (87.2%), and 4.79±0.01 CFU/ml (69.1%), respectively. Thus, treatment with chlorine was more potent in induction E. coli O157 into VBNC state after 30 min. of application rather than hydrogen peroxide which failed in inducing the bacteria into VBNC at the same time points. The PMA-qPCR method, which was used to find the rfbE gene of E. coli O157, showed that the VBNC cells were still alive and working. This suggests that PMA-qPCR could be a useful way to find the VBNC state. This study concluded that in all treatments, whether by using chlorine or H2O2 does not have the ability to kill E. coli O157. The resuscitation of VBNC E. coli cells has been studied for the purpose of risk control of recovered pathogenic bacteria Therefore, From the food safety point of view new formulation are highly required to control VBNC E. Coli. In addition, PAM-q PCR is considered a rapid method in detecting the VBNC organism. The potential influences of VBNC E. coli O157 on human health were discussed and the better ways to clean surfaces that human touch.
Keywords: Escherichia coli O157:H7, Chlorine, Hydrogen peroxide, PMA-qPCR, Resuscitation
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October 2024
Vol. 12, Sp. Iss. 1
