Survival of Salmonella enterica in cut peppers stored under low relative humidity at distinct temperatures

Outbreaks involving peppers contaminated with Salmonella enterica have been reported worldwide. Despite the consumption and use of raw cut peppers in fillings and finger foods, the survival of S. enterica in minimally processed peppers remains uninvestigated. This study assessed the survival of outbreak linked strains of S. enterica on cut peppers (Capsicum annuum L.) at different temperature and low relative humidity (RH) conditions. Disinfected pepper fruits (5 min immersion in sodium hypochlorite solution; 0.15 μL/mL) were cut in pieces (3 cm3) and spot inoculated with an inoculum of S. Enteritidis resistant to nalidixic acid (15 μg/mL) and S. Typhimurium resistant to tetracycline (15 μg/mL), to achieve final counts of ~4.5 log CFU/g pepper/strain. Inoculated samples were placed in desiccators containing a saturated solution of lithium chloride to create a controlled RH environment (~15% RH) and stored at 7, 14, and 21 °C. At time intervals from 0 to 144 h, viable cells of S. Enteritidis and S. Typhimurium were enumerated on BHI agar containing nalidixic acid or tetracycline, respectively, using the microdrop technique, with a limit of detection of 1.5 log CFU/g. After 24 h of storage at 7 °C, counts of both strains decreased (p < 0.05) by approximately 1 log CFU/g. After 96 h of storage at 7 °C, no viable counts of S. Typhimurium were recovered, while counts of S. Enteritidis were around 3.5 log CFU/g. When cut pepper samples were stored at 14 °C and 21 °C, counts of S. Enteritidis and S. Typhimurium were approximately 3.5 and 3.0 log CFU/g, respectively, until the end of the storage period evaluated (144 h). These findings highlight the ability of S. Enteritidis strain to survive in cut peppers at ~15% RH.