A Microbial Survey Of Office Coffee Cups And Effectiveness Of The FreshCUP™ System For Reduction Of Bacteria.

Charles P. Gerba, Ph.D
Ralph Meer, Ph.D
Carlos E. Enriquez, Ph.D
University of Arizona


The purpose of this study was to assess the concentration and types of bacteria found in coffee cups and food preparation areas in offices.

The concentration and occurrence of coliform bacteria in office coffee preparation areas was found to be greater than that found in household kitchens - The numbers of bacteria in used coffee cups averaged 1.0 X 105 colony forming units (CFU) and ranged from 5.4 x 104 to 3.0 x 105 CFU.

Bacterial types identified in the cups included Enterobacter cloacae, Enterobacter aggoerans, Klebsiella pneumoniae, Citrobacter frundii, Serratia liquefacians, Serratia macesans, and Acinetobacter caloaceticus.

While these bacteria do not usually cause illness in normal healthy individuals, they may cause infections in immunocomprised individuals.

Sixty percent of the cups contained coliform bacteria which is greater than the 10% observed in household cutlery and cookery.

Wiping the cups with a moist sponge or dish cloth result in significant contamination of the cups with bacteria (7.3 X 104 to 5.5 X 107 in a lO-ml rinse of the cup) including coliform bacteria and E. coli.

It was demonstrated that the FreshCup system completely eliminated coliform bacteria and E. coli presence in the cups.

In addition total bacteria numbers were reduced by greater than 99.9% or completely eliminated.

Testing Sanitization Power At BioScience Technology Laboratories


This test checked the sanitizing power of the detergent and the cup-washer unit in 'real operating conditions' (Report 3180/ R 4416).

Ceramic drinking cups were contaminated on the inside and outside by the mouth of a healthy user. A specimen was taken from every cup before and after washing in order to count bacteria colonies.

The purpose of this test was not to identify bacteria, only to test general sanitizing power for all types of bacteria found on cups - working on the assumption that these bacteria are also present in the mouth's natural flora.

Massive growth ++++
Absence of growth -
Wash program: General count on cup before washing General count on cup after washing
Cold Cycle ++++ -
Hot Cycle ++++ -


On both cycles inspected, the sanitizing of cups after the washing program was found to be completely effective.


The purpose of this test was to inspect sanitizing power of the detergent and cup-washing unit for a spectrum of 'problematic' micro-organisms cultivated for the test in laboratory conditions (Report 3876 R-5523).

Concentration of micro-organisms before washing was 1,000,000 colonies per milliliter.

Sanitizing Power tested:

  • on short cycle (contact time - 5 seconds)
  • on long cycle (contact time - 30 seconds)
Contaminant Contam. Type Count before washing Count after short cycle Count after long cycle
Staphylococcus aureus Violent bacteria found in ulcers in oral cavity ++++ - -
Streptococcus viridans Violent bacteria commonly found in mouth flora ++++ - -
Proteus vulgaris Common intestinal bacteria ++++ - -
Salmonela enteritidis Common intestinal G-C bacteria ++++ - -
Pseudomonas aeruginosa Violent bacteria that is likely to cause wounds ++++ - -
Streptococcus faecalis Common indigestive bacteria likely to also appear in a mouth with infected teeth ++++ - -
Candida albicans Yeast ++++ - -
Saccharomyces cerevisiae Yeast ++++ - -


The FreshCUP™ 1.2 BIOCLEANSER has total sanitizing power both on the long and short cycles and is effective against all micro-organisms on the above list as well as a long list of additional micro-organisms tested abroad.