Comparing the survival of salmonella in soils amended with pecan shells and poultry manure

Authors: Bardsley, Cameron; KHAREL, KARUNA - Louisiana State University; Chasteen, Kaicie; Sherman, Samantha; Pisani, Cristina

Submitted to: Journal of Food Protection
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 4/13/2026
Publication Date: 4/16/2026
Citation: Bardsley, C.A., Kharel, K., Chasteen, K.S., Sherman, S.H., Pisani, C. 2026. Comparing the survival of salmonella in soils amended with pecan shells and poultry manure. Journal of Food Protection. 89(6). https://doi.org/10.1016/j.jfp.2026.100787.
DOI: https://doi.org/10.1016/j.jfp.2026.100787

Interpretive Summary: The use of chicken manure is often used as a soil amendment for agricultural crops and can improve soil fertility, but manure amendments can also enhance the survival of pathogens like Salmonella. Pecan shells are often discarded as waste but have been shown to have antimicrobial properties. This study looked at the survival of Salmonella in ground pecan shells and chicken manure over a 28 day period and also compared the survival of Salmonella in soil amended with ground pecan shells and chicken manure over a 56 day period. Salmonella survived longer in the ground pecan shells compared to the chicken manure. This is likely due to the ammonia that is in chicken manure at high levels. But once the ground pecan shells and chicken manure were incorporated into the soil, Salmonella died off faster in soil amended with ground pecan shells than in soil amended with chicken manure. Soil amended with chicken manure extended the survival of Salmonella. The Salmonella died in soil amended with ground pecan shells at a similar rate to soil that did not have any amendments added. This means that ground pecan shells do not promote the survival of Salmonella when incorporated into the soil as an amendment.

Technical Abstract: Pecan shells have antimicrobial properties but are generally viewed as a waste product that is often discarded. Poultry manure is often used as a soil amendment but has been shown to promote the survival of foodborne pathogens in the soil. The objective of this research was to first compare the die-off of Salmonella in inoculated ground pecan shells and poultry manure, and then to evaluate its survival in soils amended with pecan shells, poultry manure, or a mixture of both pecan shell and poultry manure, compared with unamended soil. Inoculated ground pecan shells and poultry manure were enumerated 0-, 1-, 3-, 7-, 10-, 14-, 21-, and 28-days post-inoculation. Soil treatments (unamended, pecan shell amended, poultry manure amended, and mixed) were inoculated with Salmonella and enumerated 0-, 1-, 3-, 7-, 10-, 14-, 21-, 28-, 42-, and 56-days post-inoculation. Die-off models were generated using GInaFit. A more rapid Salmonella die-off was observed in poultry manure compared to ground pecan shells, with reductions of 5.28 and 1.70 log by day 14, respectively. The die-off data were best fit to a Weibull model with shape parameter (p) values of 1.63 ± 0.12 and 0.39 ± 0.02 in poultry manure and ground pecan shells, respectively. In soil, a higher initial Salmonella die-off was observed in the pecan shell amended treatment; however, by day 56 the greatest reduction occurred in the unamended soil (5.09 log CFU/g), followed by the pecan shell amended (3.94 log CFU/g), mixed (2.85 log CFU/g), and the poultry manure amended (2.81 log CFU/g) soils. A biphasic model was the best fit the soil treatment data. The results of this study show that pecan shells could be a potential soil amendment that, unlike poultry manure, does not promote the survival of Salmonella in soil.