title: Impact of cleaning and disinfection on the non-culturable and culturable bacterial loads of food-contact surfaces at a beef processing plant.
abstract: We assessed the impact of industrial cleaning and disinfection (C&D) on colony-forming units (CFUs), viable (culturable and viable but non-culturable) cells and on total cells (viable and dead cells). Bacterial loads on polyvinyl chloride (PVC) and stainless steel surfaces in a cutting room at a beef processing plant were determined before and after C&D by real-time PCR to quantify cells from successive swabs from surfaces with or without an ethidium monoazide pre-treatment and by CFU counts on tryptone soy agar. Agar contact plates were also applied after C&D for comparison. Before C&D, total cells reached 5.4 and 4.7 log cells/cm(2), viable cells 4.0 and 4.4 log cells/cm(2) and CFUs 3.1 and 2.9 log CFU/cm(2) on PVC and stainless steel surfaces, respectively. Although C&D left surfaces visually clean, it did not lead to a significant reduction in total cells. Significant reductions were only observed on PVC for CFUs: 0.8 log and on stainless steel surfaces for viable cells and CFUs: 0.8 and 1.5 log, respectively. Our results show that CFUs were both more easily detached and killed on stainless steel surfaces than on PVC surfaces. Other important results include the following observations: 1) a single swabbing detached only between 2 and 27% of the actual bacterial load; 2) after C&D, the difference between the actual culturable population and the one assessed by one agar contact plate was 1.9 and 2.7 log CFU/cm(2) on PVC and stainless steel surfaces, respectively.
authors: Laboratory of Food Safety, French Agency for Food, Environmental and Occupational Health & Safety (ANSES), 23 avenue du Général de Gaulle, 94700 Maisons-Alfort, France.
authors: Elissa
authors: E
authors: Khamisse
authors: Olivier
authors: O
authors: Firmesse
authors: Souad
authors: S
authors: Christieans
authors: Danielle
authors: D
authors: Chassaing
authors: Brigitte
authors: B
authors: Carpentier
mesh_terms: D000818:Animals; D001419:Bacteria / Q000254:growth & development / Q000302:isolation & purification; D058491:Bacterial Load; D002417:Cattle; D015169:Colony Count, Microbial; D004203:Disinfection / Q000379:methods; D004866:Equipment Contamination; D005511:Food Handling / Q000295:instrumentation*; D008460:Meat / Q000382:microbiology*; D010944:Plants; D011143:Polyvinyl Chloride; D060888:Real-Time Polymerase Chain Reaction; D013193:Stainless Steel
chemical_list: D013193:Stainless Steel; D011143:Polyvinyl Chloride