Impact of sanitizer application on Salmonella mitigation and microbiome shift on diced tomato during washing and storage

This study examined the shift in Salmonella and indigenous microbiota on diced tomato after washing with three different sanitizers and during post-wash cold storage. Roma tomatoes were inoculated with a Salmonella cocktail (initial level similar to 5.6 CFU g(-1)), diced and washed along with uninoculated diced tomato in simulated flume wash water with sanitizers, including 10 mg L-1 free chlorine (FC10), 90 mg L-1 peracetic acid (PA90), PA90 in combination with a proprietary acidified surfactant blend (PS90), and unsanitized control (CK). Salmonella, total mesophilic aerobic bacteria (MAB), and yeast and mold (YM) populations on both inoculated and uninoculated samples were measured before and after washing, and during storage at 4 degrees C. 16S rRNA amplicon sequencing was also performed to determine the shift in bacterial microbiome. Washing with all tested sanitizers, especially PS90 (> 4 log Salmonella reduction), reduced Salmonella and MAB populations on inoculated diced tomatoes. Additionally, application of sanitizers mitigated Salmonella cross-contamination onto uninoculated samples. PS90 treatment inhibited the proliferation of most dominant bacteria on diced tomatoes during storage, including Erwiniaceae, Curtobacterium, Pantoea, Erwinia and Enterobacterales, which may benefit product quality and safety.

Automated summary

This study investigated the effects of three different sanitizers on the shift of Salmonella and indigenous microbiota on diced tomato, as well as during post-wash cold storage. The results showed that washing with all tested sanitizers, especially PS90, significantly reduced Salmonella and MAB populations on the inoculated diced tomatoes. The application of sanitizers also prevented Salmonella cross-contamination on uninoculated samples and inhibited the proliferation of dominant bacteria during storage.