Cellulosic biofuels hold a promising future.  In order to convert the cellulosic biomass substrate into ethanol, via the biochemical conversion platform, the biomass must be pretreated.  In a dilute acid pretreatment, the hemicellulosic sugars are extracted from the lignin/hemicellulose/cellulose matrix, from which the monomeric carbohydrates are released prior to fermentation.  Interestingly, bacterial contaminants have been reported to occur during fermentation, particularly in corn-based ethanol production.  Some of the most common contaminants in the production of corn-based ethanol are lactic acid bacteria.  To combat this contaminant problem, distilleries add antibiotics to the fermentation broth to deter the growth of undesired organisms. Antibiotic use adds a significant burden to the production of corn-based biofuels and to the disposal of antibiotic-laden broth by the increasing costs. The objective of this study was to determine if switchgrass-based ethanol production would be faced with contamination problems similar to those of corn-based ethanol.  Switchgrass extracts from hot water pretreatments at 85 °C and 240 °C were collected and 0.1 mL aliquots were platted at set time intervals onto Tryptic soy agar (total plate counts) and de Man, Rogosa and Sharpe (MRS) agar, which is specific for Lactobacillus.  Plates were incubated for 24-48 h at 37 °C and colony forming units were enumerated.  Data were recorded on Microsoft Excel spreadsheets and analyzed with Excel or JMP 6.0.  Preliminary data indicated that bacterial contaminants were noted after seven days when extracts were left at room temperature.