Enhanced inactivation of Salmonella Typhimurium from blueberries by combinations of sodium dodecyl sulfate with organic acids or hydrogen peroxide

- Addition of SDS to an organic acid washing enhanced Salmonella inactivation.
- Addition of SDS to hydrogen peroxide solutions enhanced Salmonella inactivation.
- Both treatments showed similar Salmonella reductions as 200 ppm chlorine solution.
- They did not change the color, pH and anthocyanin content of blueberries.
- Both treatments decreased counts of yeasts and molds throughout the 3-day storage.

Increasing consumption of raw blueberries has led to the need for improved food safety in the berry fruit industry. This study was undertaken to evaluate an enhanced Salmonella inactivation on blueberries by washing with sodium dodecyl sulfate (SDS) in combination with one of common antimicrobial agents (chlorine, lactic acid, acetic acid, citric acid and hydrogen peroxide). In addition, the impacts of most effective treatments on apparent quality, total phenolic, anthocyanin content, mold and yeast, and Salmonella survivors during the storage of blueberries were also determined. Maximum reductions of Salmonella after washing with 0.5 mg/ml acetic acid plus 5000 ppm SDS and 200 ppm hydrogen peroxide containing 5000 ppm SDS were 4.0 and 4.2 log10 CFU/g, respectively. Addition of SDS enhanced Salmonella inactivation of the acetic acid or hydrogen peroxide solutions. These treatments showed similar Salmonella reductions with 200 ppm chlorine (P > 0.05). None of these washings decreased the total phenolic, anthocyanin content and apparent quality. Following the two effective antimicrobial washes, 0.5 mg/ml acetic acid plus 5000 ppm SDS and 200 ppm hydrogen peroxide containing 5000 ppm SDS, populations of Salmonella on blueberries remained constant throughout the 3-day storage with no appreciable growth. Both treatments decreased counts of yeasts and molds throughout the storage. Therefore, the use of 0.5 mg/ml acetic acid plus 5000 ppm SDS, 200 ppm hydrogen peroxide in combination with 5000 ppm SDS may have practical potential as an alternative to the use of chlorine-based washing solution for blueberries.