P-42 - Survival of Salmonella Tennessee and Lactobacillus Plantarum in Hard Cider

Hard cider (fruit wine > 0.5% alcohol by volume) has been found to be an inhospitable environment for many organisms due to its low pH and alcohol percentage. However, spoilage microorganisms, such as Lactobacillus, have been found to survive in low pH and high alcohol environments. Some studies have also shown the potential for foodborne pathogens, such as Salmonella, to survive in fermented beverages. The objective of the study was to evaluate the survival of Salmonella Tennessee (peanut butter outbreak) and Lactobacillus plantarum (ATCC 49445) in hard cider under refrigerated storage (4°C). Six commercial hard ciders (Apple, Original, Peach 1, Peach 2, Pear, Strawberry) were inoculated with Salmonella (n=132) at approximately 9.0 log CFU/mL. Peach 2 was also co-inoculated with L. plantarum (n=22) at approximately 6.0 log CFU/mL. Inoculated samples were stored at 4°C and enumerated in duplicate at 0, 0.5, 1, 2, 3, 7, 14, 21, 28, 35, and 42 days. Salmonella was plated in duplicate on Xylose-Lysine-Tergitol 4 (XLT4) agar and incubated for 18-24 hours at 35°C, and L. plantarum was enumerated on De Man-Rogosa-Sharpe (MRS) agar with sorbic acid and incubated for 48-72 hours at 35°C. Data were analyzed using Kruskal-Wallis and Dunn’s Test in RStudio version 4.3.3. Salmonella had a 6.92 log reduction in the “Pear” cider between 0.5 and 14 days, and a 7.42 log reduction in the “Pear” cider between 0.5 and 35 days (p < 0.05). “Peach 1” had a Salmonella log reduction of 4.68 CFU/mL between day 1 and days 28, 35, and 42 respectively and was below the limit of detection (1 CFU/mL) after 28 days (p < 0.05). The “Peach 2” co-inoculation had a Salmonella log reduction of 6.11 CFU/mL between day 0.5 and day 14 and was below the limit of detection after day 14. The “Original” cider showed the greatest log reduction of 7.55 CFU/mL after three days, with Salmonella recovery falling below the limit of detection after seven days. After 42 days, Salmonella recovery was below the LOD in all samples except the “Pear” flavor. After 42 days, L. plantarum was detected in the “Peach” cider with a log CFU/mL of 2.07± 0.24. Salmonella populations reduced more quickly in hard cider than Lactobacillus plantarum. Hard cider did not support the growth of Salmonella in any product at any timepoint.