In hy­gien­i­cal­ly de­mand­ing areas, such as food and phar­ma­ceu­ti­cal in­dus­try, cos­met­ics and health sec­tor, hy­giene and dis­in­fec­tion plans are an im­por­tant part of qual­i­ty man­age­ment sys­tems. These plans de­ter­mine the reg­u­lar im­ple­men­ta­tion of clean­ing and dis­in­fec­tion pro­ce­dures. To ver­i­fy the suc­cess of clean­ing and dis­in­fec­tion pro­cess­es ran­dom end prod­uct con­trols are car­ried out rou­tine­ly. Be­cause there are no suit­able fast meth­ods avail­able at pre­sent the dis­in­fec­tion suc­cess can only be ver­i­fied by con­tact plates or swab test­ing. How­ev­er, end prod­uct con­trols are very time con­sum­ing and ex­pen­sive as they have to be per­formed by ex­ter­nal lab­o­ra­to­ries. The long du­ra­tion of the in­ves­ti­ga­tion makes it im­pos­si­ble to apply any cor­rec­tive ac­tions of dis­in­fec­tion in a time­ly man­ner.

There­fore, the aim of the pro­ject was the de­vel­op­ment of a fast method for an easy and fast self-mon­i­tor­ing of sur­face dis­in­fec­tion pro­cess­es based on pro­te­oli­po­somes in­clud­ing a self­quench­ing flu­o­res­cent dye.

Mi­croor­gan­isms have a mem­brane con­tain­ing tar­get struc­tures for dis­in­fec­tant ac­tive sub­stances. These tar­get struc­tures can be sim­u­lat­ed by pro­te­oli­po­somes. There­fore they were used for the de­vel­op­ment of a test mon­i­tor.

Using var­i­ous lipids and pro­teins pro­te­oli­po­somes were pre­pared. Func­tion­al­iza­tion of pro­te­oli­po­somes was car­ried out with a flu­o­res­cent dye which had the prop­er­ty of flu­o­res­cence quench­ing (no flu­o­res­cence) de­pend­ing on high con­cen­tra­tions but emit­ted a strong flu­o­res­cence sig­nal after di­lu­tion. Im­mo­bi­liza­tion of pro­te­oli­po­somes was car­ried out on a car­ri­er ma­trix by em­bed­ding the pro­te­oli­po­somes in a hy­dro­gel. The test mon­i­tor was placed on the sur­face to be dis­in­fect­ed. By the ac­tion of the dis­in­fec­tant the pro­te­oli­po­somes were de­stroyed anal­o­gous­ly to the mi­croor­gan­isms and the in­clud­ed dye was re­leased. The qual­i­ty of the dis­in­fec­tion pro­cess could then be as­sessed by the in­ten­si­ty of flu­o­res­cence of the re­leased dye cor­re­lat­ing with the level of germ re­duc­tion and vi­su­al­ized with UV-light.

Thus, a pro­cess con­trol was de­vel­oped that can be used as part of on-site self-mon­i­tor­ing in qual­i­ty man­age­ment sys­tems, in order to de­tect pos­si­ble fail­ures in the dis­in­fec­tion pro­cess prompt­ly and if nec­es­sary to ini­ti­ate cor­rec­tive ac­tions im­me­di­ate­ly.

The research report is available on request from FRT.