Establishment of ddPCR detection technology system for three contaminants in fermented milk

Abstract

Three t ypical c ontaminant b acteria, n amely, Gluconobacter, Acetobacter, a nd Lactobacillus, w ere s elected f rom f ermented milk. The strong specific genes were screened as target sequences, and the droplet digital polymerase chain reaction (ddPCR) amplification system and reaction conditions were optimized. We established a ddPCR detection method for the three kinds of bacteria in fermented milk and then verified t he specificity an d se nsitivity of th e me thod. Ab solute qu antitative re sults were also analyzed. Results showed that ddPCR detection method for the three contaminants was specific and sensitive, and that the lowest detectable concentrations of Gluconobacter, Bacteroides, and Lactobacillus plantarum were 8.8 × 10 0 CFU/mL, 8.9 × 10 1 CFU/mL, and 9.6 × 10 1 CFU/mL, respectively. The relationship between the quantitative analysis results and ddPCR test results was good, proving the feasibility of ddPCR for absolute quantitative detection. This manuscript reports on establishment of a ddPCR detection system for three bacterial contaminants in fermented milk. The ddPCR detection system has efficient detection of targeted bacterial contaminants in fermented milks that can be valuable to the dairy industry in terms of preventing economic loss due to microbial spoilage and associated quality defects.

Potential use of plasma‐activated water on Escherichia coli for sterilization: Efficacy and mechanism

“…Therefore, it is widely regarded as an effective method for microbial inactivation. [4,5] The advantage of plasma direct sterilization is that it does not require the use of other substances, and the sterilization target is directly placed in the electric field to achieve the sterilization effect. The sterilization products of hydrogen peroxide (H 2 O 2 ) plasmas are water vapor and oxygen, which are nontoxic and have advantages such as short sterilization time and safe and reliable effects.…”

“…Research shows that when mung bean sprouts were treated with nitrogen PAW, the number of colonies decreased by 2.04‐log reduction. [ 5 ] PAW treated by 20 min reduced the numbers of E. coli , Salmonella Typhimurium , and Listeria monocytogenes by about 2.00 log colony‐forming unit (CFU)/g. [ 9 ] Jun Wang [ 10 ] used PAW to inactivate methicillin‐resistant Staphylococcus aureus (MRSA) and methicillin‐susceptible S. aureus (MSSA).…”