Attachment and colonization of Salmonella on 'Rayada', 'Golden Delicious', and 'Red Delicious' apples

Fruits and vegetables have been associated with outbreaks of disease in different countries. The apple (Malus domestica Borkh) and its products have been reported as vehicles for illness outbreaks. To create strategies to prevent pathogen survival it is necessary to understand how pathogens persist on fruit. This paper assessed the ability of Salmonella to attach to, and to colonize, the surface of three apple cultivars: 'Rayada', 'Golden Delicious' and 'Red Delicious'.

Salmonella was able to colonize and generate biofilms on the surface of apples with a soil suspension as the only source of nutrients. Significant differences in Salmonella attachment were seen among the three cultivars of apple studied. Using SEM, attached cells and the formation of exopolysaccharides and biofilms on the three apple cultivars were demonstrated. In all cultivars, the development of Salmonella was only seen in apples stored at 15 and 22 °C, with average increases in the population of 1.4 and 2.3 Log CFU/apple, respectively. At 5 °C, Salmonella growth was inhibited.

Salmonella can colonize apple surfaces under environmental conditions (relative humidity, temperature and nutrients) occurring in primary apple production. © 2018 Society of Chemical Industry.