Food and Nutrition Sciences, 2014, 5, 2033-2037 Published Online November 2014 in SciRes. http://www.scirp.org/journal/fns http://dx.doi.org/10.4236/fns.2014.521214 How to cite this paper: Speranza, B., Racioppo, A., Bevilacqua, A., Sinigaglia, M. and Altieri, C. (2014) Comparison of Direct Microbial Count Procedures for Planktonics and Sessiles Enumeration. Food and Nutrition Sciences, 5, 2033-2037. http://dx.doi.org/10.4236/fns.2014.521214 Comparison of Direct Microbial Count Procedures for Planktonics and Sessiles Enumeration Barbara Speranza, Angela Racioppo, Antonio Bevilacqua, Milena Sinigaglia, Clelia Altieri * Department of the Science of Agriculture, Food and Environment (SAFE), University of Foggia, Foggia, Italy Email: * clelia.altieri@unifg.it Received 26 August 2014; revised 20 September 2014; accepted 9 October 2014 Copyright © 2014 by authors and Scientific Research Publishing Inc. This work is licensed under the Creative Commons Attribution International License (CC BY). http://creativecommons.org/licenses/by/4.0/ Abstract In the present investigation, the sensitivity of different direct microbial count procedures applied on systems containing both planktonics and sessiles was tested. The direct count pour plate was compared with direct epifluorescent microscopic enumerations in order to evaluate the efficiency of the studied techniques in giving information about microbial activity or viability. Our results indicate that the standard plate count procedure is the most sensitive method to estimate viable and cultivable planktonic cells. On the other hand, direct enumeration by epifluorescent micros- copy may become an interesting alternative to count sessile cells. Keywords Direct Viable Count, Biofilm, Epifluorescence Microscopy, Fluorochromes 1. Introduction Accurate quantitative evaluations of bacterial populations, of biomass and of community structure are critical prerequisites for assessing the roles of bacteria in natural and technical systems (i.e. sewage or food processing plants). There is no scientific univocality on which procedure gives the best results in representing a viable mi- crobial population. Plate count methods are often employed for microbiological quantitative analyses, but they are time consuming (because of required lengthy incubations) and typically do not provide useful information concerning microbial activity, or viability. Bacteria are generally physically removed (by filtration or dilution) from the native sample and are therefore no longer subject to possible inhibitory substances or conditions that * Corresponding author.