A Multistate Outbreak of Salmonella enterica Serotype Newport Infection Linked to Mango Consumption: Impact of Water-Dip Disinfestation Technology

Abstract

Fresh produce increasingly is recognized as an important source of salmonellosis in the United States. In December 1999, the Centers for Disease Control and Prevention detected a nationwide increase in Salmonella serotype Newport (SN) infections that had occurred during the previous month. SN isolates recovered from patients in this cluster had indistinguishable pulsed-field gel electrophoresis (PFGE) patterns (which identified the outbreak strain), suggesting a common source. Seventy-eight patients from 13 states were infected with the outbreak strain. Fifteen patients were hospitalized; 2 died. Among 28 patients enrolled in the matched case-control study, 14 (50%) reported they ate mangoes in the 5 days before illness onset, compared with 4 (10%) of the control subjects during the same period (matched odds ratio, 21.6; 95% confidence interval, 3.53- infinity; P=.0001). Traceback of the implicated mangoes led to a single Brazilian farm, where we identified hot water treatment as a possible point of contamination; this is a relatively new process to prevent importation of an agricultural pest, the Mediterranean fruit fly. This is the first reported outbreak of salmonellosis implicating mangoes. PFGE was critical to the timely recognition of this nationwide outbreak. This outbreak highlights the potential global health impact of foodborne diseases and newly implemented food processes.

Genetic diversity of food originated Salmonella isolates

“…In addition to this, it has been used in typing Salmonella in human patients, animal sources and foods because of its discriminatory power and high reproducibility [14][15][16]. Numerous reports have been documented that using the highly discriminatory technique of PFGE was successful to track the source of Salmonella infections in different serovars [17][18][19][20][21]. However, PFGE does not display equal sensitivity in different serovars [14,21] and it has several limitations including changes in DNA concentration, percent of agarose in the gel, applied voltage and gel temperature.…”

Scientific Opinion on the risk posed by pathogens in food of non-animal origin. Part 1 (outbreak data analysis and risk ranking of food/pathogen combinations)

“…melons, oranges, papaya, mangoes) (CDC, 2006a(CDC, , 2010(CDC, , 2011b(CDC, , 2012a(CDC, , 2012bGibbs et al, 2009;Loharikar et al, 2012;Noel et al, 2010;Sivapalasingam et al, 2003;Vojdani et al, 2008); salads and other leafy greens (Barton Behravesh et al, 2011;CDC, 2006b;Gajraj et al, 2012;Nygard et al, 2008); nuts, seeds and derived products, e.g. almonds, peanuts, coconut and sesame seeds (Brockmann et al, 2004;Cavallaro et al, 2011;Koch et al, 2005;Rabsch et al, 2005;Rimhanen-Finne et al, 2011;Teoh et al, 1997;Unicomb et al, 2005;Ward et al, 1999), corn or rice snacks (Joseph et al, 1991).…”

Salmonella and produce: Survival in the plant environment and implications in food safety

“…30 Salmonella ser Newport was eventually traced back to the wash water used in the processing facility. The wash tanks in the facility were susceptible to contamination since they were unenclosed and frogs, birds and bird feces were identified near the tanks.…”

“…The wash tanks in the facility were susceptible to contamination since they were unenclosed and frogs, birds and bird feces were identified near the tanks. 30 The immersion of warm fieldgrown tomatoes in cool water in a flume system may also cause the internalization of water as the plant cells contract at the stem scar of the tomato. 45 This has led to the process of heating dunk tank water 10°F above the temperature of the tomato pulp.…”

“…The use of contaminated water during processing will introduce pathogens to the produce surface, but may also cause the internalization of pathogens depending on the produce type and water temperature. 30,45 The contact between warm fruit and cool water will cause the plant cells to contract, resulting in the possible internalization of the water. This process has been shown to occur with both mangoes and tomatoes.…”