|KELLER, SUZANNE - Food And Drug Administration(FDA)|
Submitted to: Journal of Food Protection
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 1/31/2020
Publication Date: 4/27/2020
Citation: Gurtler, J., Keller, S.E., Fan, X., Olanya, O.M., Jin, Z.T. 2020. Survival of desiccation-resistant salmonella on apple slices following antimicrobial immersion treatments and dehydration. Journal of Food Protection. 83:902-909.
Interpretive Summary: Dried fruits have been recalled for contamination with Salmonella. This study was conducted to determine the survival of Salmonella on apple slices after dehydration with or without pretreatment in antimicrobial solutions. Of the six varieties of apples tested, the greatest reduction of Salmonella occurred on Granny Smith apple slices, which also had the lowest pH. The greatest reduction after drying, based on antimicrobial treatment, was two-minute treatments with either 0.5 percent fumaric acid or 0.5 percent sodium acid sulfate. These results may assist the apple industry in preparing dried apple slices that are free from Salmonella.
Technical Abstract: Salmonella is capable of surviving dehydration processes of various foods including dried fruit. Dehydrated fruit, including dried coconut (Cocos nucifera) and dried apple (Malus sp.) slices, have been the subject of recalls due to contamination with Salmonella. A study was conducted to determine the survival of Salmonella on six cultivars of apple slices after dehydration as well as survival following treatment with an antimicrobial solution (0.5 percent, wt./wt.) and dehydration. Six cultivars of apples (Envy, Gala, Red Delicious, Fuji, Pink Lady, Granny Smith) were cored and sliced into 0.4 mm rings, inoculated with a five-strain composite of desiccation-resistant Salmonella and dehydrated at 60 degrees Celcius for 5 hours. Subsequently, Gala apple slice were treated in 0.5 percent solutions of one of eight antimicrobial rinses for two minutes and then dehydrated at 60 degrees Celsius for 5 hours. Antimicrobial solutions were potassium sorbate (PS), sodium benzoate (SB), ascorbic acid (AA), propionic acid (PA), lactic acid (LA), citric acid (CA), fumaric acid (FA), and sodium acid sulfate (SAS). Reduction of Salmonella populations varied according to apple cultivar. Reductions (in log CFU) were Envy (1.69), Gala (2.09), Red Delicious (2.77), Fuji (2.93), Pink Lady (3.15), and Granny Smith (3.77). Greater numbers of Salmonella (p<0.05) were significantly inactivated on Granny Smith, Pink Lady and Fuji apples than on Gala and Envy apples. Survival of Salmonella on Gala apple slices (log CFU) following antimicrobial treatments and dehydration were untreated control (5.58), PS (4.76), SB (3.90), AA (3.29), PA (3.13), LA (2.89), CA (2.83), FA (1.76), and SAS (0.0). Lower survival was obtained by pre-treating apple slices with either FA or SAS before dehydration than all other antimicrobial treatments. These results may provide methodology applicable to the food industry for increasing the inactivation of Salmonella during the dehydration of apple slices.