Salmonella collected from nest run cart shelves in commercial shell egg processing facilities

Abstract

Salmonella, a member of the bacterial family Enterobacteriaceae, may be recovered from foods and processing facilities. High levels of Enterobacteriaceae in the processing plant environment can be an indication of inadequate sanitation. This experiment was designed to determine if nest run egg carts serve as reservoirs for Salmonella. Eggs that are produced by hens not housed in buildings connected to the processing plant are referred to as nest run. Many of these eggs are transported to a central processing facility before they are washed, graded, and packed. Two plants in the Southeastern United States were sampled; one was a mixed operation and the other was an off-line operation. On each of 3 visits, 5 shelves on each of 5 carts were sampled (n = 25/visit). A 12 × 12 cm area on each shelf was swabbed with a sterile gauze pad moistened with PBS and transported on ice back to the laboratory. Each swab was preenriched in buffered peptone at 37°C for 24 h, selectively enriched using TT and Rappaport-Vassiliadis broth at 42°C overnight, then plated onto brilliant green sulfa and XLT-4 incubated at 37°C for 24 h. Presumptive colonies were transferred to lysine iron agar and triple sugar iron slants for 24 h at 37°C. Isolates with presumptive reactions were confirmed using commercial polyclonal antisera. After initial confirmation, serogrouping was performed using commercial antisera. Mixed-operation swab samples were 12% positive for Salmonella, whereas off-line samples were 36% positive for Salmonella; isolates were confirmed as serogroups B, C1, and C2. Kauffman-White serotyping was performed by a contract laboratory. Serotypes (n = 30) recovered were Anatum, Heidelberg, Infantis, Kentucky, Mbandanka, and Typhimurium. This work demonstrated that nest run egg carts may serve as reservoirs for Salmonella in the shell egg processing environment.

Survey of Salmonella Contamination in Chicken Layer Farms in Three Caribbean Countries

“…Adesiyun et al (1) used pulse-field gel electrophoresis to determine the relationships among Salmonella Enteritidis isolates recovered from each of the Caribbean countries studied. Salmonella serotypes differ among layer farms and countries (9,28,29,34), and all serotypes recovered in the present study have been documented previously in the Caribbean region (1,10,20).…”

Control of Salmonella Contamination of Shell Eggs—Preharvest and Postharvest Methods: A Review

“…Overall, the authors found that aerobic plate counts (APC) of eggs obtained from the in‐line type of facility were higher in comparison to those obtained from the off‐line one. Also, Musgrove and others () determined the possibility of nest run egg carts to act as reservoir of Salmonella , with comparisons between an off‐line facility and a mixed‐operation one (with in‐line processed eggs and supplementation with off‐line ones). It appears that Salmonella prevalence in the off‐line facility (12%) was significantly different ( P < 0.001) from the mixed‐operations one (36%).…”

“…Usually this happens without any lesions and furthermore, when egg storage conditions allow it, this foodborne pathogen may be isolated from the shell egg, as it survives in the forming egg (Gast and others ; Gantois and others ; Raspoet and others ; Howard and others ). Transmission of this serotype may happen either vertically (Gast and Beard ; Galàn 2001; Groisman ; Gast and others ; Gast and others ; Gyles and others ; Gast and others ; Ibarra and Steele‐Mortimer ; Li and others ; Mastroeni and others ; Dawoud and others ; De Vylder and others ; Desin and others ; Linke and Goldman ; Shah and others ; Howard and others ; Kumar ) or horizontally (Holt ; Holt and others ; Jones and others ; Davies and Breslin ; De Reu and others ; Musgrove and others ).…”

Application of Molecular Approaches for Understanding Foodborne Salmonella Establishment in Poultry Production

“…Risk of Salmonella external contamination of eggs during egg processing does still exist in the U.S. and other developed countries. In-line egg processing facilities where the egg processing facilities are physically connected to the egg layer operation, off-line operations where they are not physically connected, and mixed-line operations that include a combination of in-line processing as well as externally shipped in eggs have been shown in several studies to be a source of Salmonella contamination with or without egg washing [76][77][78]. In addition, numerous opportunities for general microbial cross contamination occur in these types of operations as the eggs move through the processing facilities [79,80].…”

“…In addition, numerous opportunities for general microbial cross contamination occur in these types of operations as the eggs move through the processing facilities [79,80]. In a series of studies on mixed-line and offline egg processing facilities, Musgrove and coworkers [78,81] demonstrated that metal carts with unpainted plywood shelves, commonly referred to as nest run carts could serve as sources of microbial cross contamination.…”