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ARS Home » Northeast Area » Beltsville, Maryland (BARC) » Beltsville Agricultural Research Center » Environmental Microbial & Food Safety Laboratory » Research » Publications at this Location » Publication #337555
Research Project: Characterization and Mitigation of Bacterial Pathogens in the Fresh Produce Production and Processing Continuum

Location: Environmental Microbial & Food Safety Laboratory

Title: Influence of amendment type on persistence of Salmonella Newport in soil

Author
item TEICHMAN, JUNE - University Of Delaware
item Sharma, Manan
item KNIEL, KALMIA - University Of Delaware

Submitted to: International Association for Food Protection
Publication Type: Abstract Only
Publication Acceptance Date: 3/17/2017
Publication Date: N/A
Citation: N/A

Interpretive Summary:

Technical Abstract: Introduction: Salmonella Newport is a foodborne pathogen isolated from several environmental reservoirs on the DelMarVa Peninsula and has been associated with several produce-related outbreaks.Little is known about interactions between S. Newport and soil amendments used as fertilizers. Purpose: The purpose of this study is to determine Salmonella Newport persistence and resuscitation in soils containing poultry litter (PL)-based or chemical fertilizer amendments. Methods: Salmonella Newport (rifampicin-resistant) at 4.4 log CFU/pot was inoculated into pots (7.5cm x 5.5cm) containing soil amended with either: 1) PL (raw); 2) heat-treated poultry litter pellets (HTPP) or 3) urea (U) (chemical fertilizer) to provide equivalent levels of nitrogen to soil. Inoculated pots were stored in a growth chamber (20oC, 10 h day length). Pots were irrigated weekly (day 0, 7, 13), and three samples of each treatment were taken immediately before, and 24h after irrigation. Bacterial populations were examined over 2 weeks and enumerated on Xylose lysine deoxycholate agar with rifampicin (XLDR). Soil samples were dried to determine moisture content Recovered populations of S. Newport (log CFU/gdw (gram dry weight) were analyzed using an one-way ANOVA and student’s T-test in JMP. Results: Mean S. Newport populations in PL-amended soils were significantly (p<0.05) higher (3.8+0.58 log CFU/gdw)compared to populations in HTPP-amended (1.9+1.8 log CFU/gdw) or U-amended (1.4+1.8 log CFU/gdw) soils. S.Newport populations were present but fell below the limit of detection (<0.62 log CFU/g) in HTPP- and U-amended soils on days 6, 7, and 8. However, populations of S. Newport resuscitated to 3.68 log CFU/g in HTPP-amended soils on day 13, and to 2.99 log CFU/mL in U-amended soils on day 14. Significance:These data suggest that soils containing PL may support higher populations of S.Newport than HTPP and U-amended soils, but that S. Newport populations are dynamic in both U- and HTPP-amended soils under specific conditions.