TY - JOUR
T1 - Evaluation of factors influencing dairy biofilm formation in filling hoses of food-processing equipment
AU - Fysun, Olga
AU - Kern, Heike
AU - Wilke, Bernd
AU - Langowski, Horst Christian
N1 - Publisher Copyright:
© 2018 Institution of Chemical Engineers
PY - 2019/1
Y1 - 2019/1
N2 - Biofilms in dairy-processing environments lead to increased opportunities for microbial contamination of processed products. The aim of this work is to investigate the influence of factors that can affect biofilm onset in a dairy-filling test hose. Bacterial composition (monoculture Pseudomonas fragi, polyculture), fat content of milk (1.5%, 3.5%), flow condition (laminar, turbulent), and contact material (PTFE, stainless steel 1.4404) were considered as factors at a constant low temperature of 5.5 ± 0.5 °C. Biofilms were visualized by microscopy (CLSM) and analysed by counting viable cells, ATP-bioluminescence assay, and staining method for biomass quantification. The correlation between these methods was evaluated, since the chosen methods detect different characteristics of biofilms. Furthermore, enzymatic cleaning was applied after each experimental run. The results showed that the bacterial composition, material type, and fat content significantly affect the results of viable-cell counting (p ≤ 0.05). Flow conditions and material type both have significant influence upon biomass-quantification results (p ≤ 0.001). The highest positive Pearson correlation was estimated between the ATP-bioluminescence and biomass methods (0.550), while the lowest correlation was found between viable-cell counting and biomass quantification (0.345). Enzymatic treatment showed a good result for the cleaning of the PTFE-hose liner in the dairy-filling hose.
AB - Biofilms in dairy-processing environments lead to increased opportunities for microbial contamination of processed products. The aim of this work is to investigate the influence of factors that can affect biofilm onset in a dairy-filling test hose. Bacterial composition (monoculture Pseudomonas fragi, polyculture), fat content of milk (1.5%, 3.5%), flow condition (laminar, turbulent), and contact material (PTFE, stainless steel 1.4404) were considered as factors at a constant low temperature of 5.5 ± 0.5 °C. Biofilms were visualized by microscopy (CLSM) and analysed by counting viable cells, ATP-bioluminescence assay, and staining method for biomass quantification. The correlation between these methods was evaluated, since the chosen methods detect different characteristics of biofilms. Furthermore, enzymatic cleaning was applied after each experimental run. The results showed that the bacterial composition, material type, and fat content significantly affect the results of viable-cell counting (p ≤ 0.05). Flow conditions and material type both have significant influence upon biomass-quantification results (p ≤ 0.001). The highest positive Pearson correlation was estimated between the ATP-bioluminescence and biomass methods (0.550), while the lowest correlation was found between viable-cell counting and biomass quantification (0.345). Enzymatic treatment showed a good result for the cleaning of the PTFE-hose liner in the dairy-filling hose.
KW - Biofilm
KW - Dairy processing equipment
KW - Dairy products
KW - Enzymatic cleaning
KW - Pseudomonas fragi
UR - http://www.scopus.com/inward/record.url?scp=85056147663&partnerID=8YFLogxK
U2 - 10.1016/j.fbp.2018.10.009
DO - 10.1016/j.fbp.2018.10.009
M3 - Article
AN - SCOPUS:85056147663
SN - 0960-3085
VL - 113
SP - 39
EP - 48
JO - Food and Bioproducts Processing
JF - Food and Bioproducts Processing
ER -