The pre-harvest use of supplements to reduce the incidence of crop contamination in turkeys was investigated. As opposed to other studies that used a carbohydrate or lactic acid bacteria supplementation prior to slaughter in extended feed withdrawal times, this study challenged poults before their natural nocturnal fast to determine the effects of supplementation on Salmonella challenge during grow-out. Three-week-old turkey poults, on a 2.5% lactose and Lactobacillus acidophilus (1x10⁹ organisms/liter) drinking water supplement from day of hatch, were orally challenged with 1.7x10⁸ naldixic-acid resistant Salmonella enterica serovar Typhimurium strain 4232. Crop ingesta and tissue were collected at timepoints 0.5, 4, 8, and 24 hours post challenge. Crop ingesta and crop wall tissue were separately weighed and pulverized in a stomacher. Ten-fold serial dilutions were made in peptone water and plated on XLT 4 media. An immunohistochemical staining procedure was used to explore the effects of supplementation on invasion, clearance, and multiplication of Salmonella typhimurium in vivo. Results from this study indicate that lactose and L. acidophilus supplementation did not reduce S. typhimurium colonization after challenge.