When 40 Campylobacter jejuni isolates from human clinical cases, raw chicken and water were tested, 29 (72·5%) could be adapted to grow on nutrient agar under aerobic conditions. Once adapted, these isolates could grow on repeated aerobic subculture. An aerobically‐grown Camp. jejuni isolate survived almost as well as the same isolate grown microaerophilically in sterile chicken mince at 5 °C, and survival of a cocktail of Camp. jejuni isolates under both atmospheres was comparable at 25 °C. However, at 37 °C, the decline in numbers of the aerobically‐grown cells was greater. Survival of cells on chicken nuggets was poorer than in chicken mince. In filter‐sterilized stream water incubated aerobically at 5 °C, survival of inocula grown under different atmospheres was again similar, but slightly better with the microaerophilically‐grown cells. Adaptation to aerobic growth was not found to enhance survival under aerobic conditions.

Aims:  To survey the prevalence of Salmonella in imported and domestic pet chews for assessing their potential in introducing novel pathogenic and antimicrobial resistant Salmonella serotype clones into New Zealand, and as vehicles of salmonellosis in the domestic home environment. Methods and Results:  Three hundred samples, each of imported and domestic pet chews, were examined bacteriologically for the presence of Salmonella. Salmonella cells in the pre‐enrichment culture were concentrated by using Dynabeads®, and then selective enrichment and plating were performed by a method described in the Bacteriological and Analytical Manual, USFDA. Salmonella was isolated from 16 (5·3%) of the imported and 20 (6·7%) of the domestic pet chews, but the prevalences of Salmonella in imported and domestic products were not significantly different. All Salmonella isolates were serotyped and genotyped by pulsed‐field gel electrophoresis and antimicrobial susceptibility determined by the Clinical and Laboratory Standards Institute disc diffusion methods. Salmonella Borreze has never been recorded earlier in New Zealand and was detected from Australian raw hide. Three isolates of Salmonella London were resistant to ampicillin and gentamicin, and two isolates of Salmonella Infantis were resistant to nalidixic acid, one of which was also resistant to streptomycin. Conclusions:  Novel pathogenic and antimicrobial‐resistant Salmonella are being introduced into New Zealand through the import of pet chews. This indicates that pet chews are a potential source of exposure to Salmonella in the domestic home environment. Significance and Impact of the Study:  Contaminated pet chews are potential sources of Salmonella infection for domestic pets, and humans are at risk of exposure either directly by contact through handling or inadvertently by cross‐contamination of food or food‐contact surfaces in home environments.

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Epidemiological evidence suggests that Salmonella on New Zealand eggs is not an important pathway for human salmonellosis. However, robust nationally representative data for Salmonella contamination of eggs is not available to support this. To better understand the exposure of New Zealand commercial eggs to Salmonella, a cross-sectional survey collected data on prevalence and serotypes of Salmonella in the feed, laying sheds (feces, dust, and boot or manure belt swabs), and packhouses (egg contact surfaces) of New Zealand commercial egg layer farms. Salmonella was not detected on 16 of 28 surveyed farms, and 4 farms had only one positive sample. Of the 43 (13.3%) of 323 Salmonella-positive samples, dust samples had the highest prevalence (19 of 67, 28.4%), followed by boot or manure belt swabs (11 of 67, 16.4%), feces (7 of 67, 10.4%), packhouse egg contact surfaces (5 of 87, 5.7%), and feed (1 of 33, 3.0%). A significantly higher prevalence was from caged (33 of 75, 44.0%; P < 0.001) compared with cage-free (4 of 126, 3.2%) systems, yet multiple practices differ between laying systems, which could influence prevalence. Salmonella-positive packhouse samples were only identified on the three farms with the highest laying shed prevalence, and isolates were genetically related (as determined by single nucleotide polymorphism analyses) suggesting cross-contamination between the laying shed and packhouse surfaces. Serotypes isolated included Salmonella Infantis, Salmonella Thompson, Salmonella Typhimurium, Salmonella Anatum, and Salmonella Mbandaka. Importantly, Salmonella Enteritidis, which causes egg-associated outbreaks internationally, was not isolated. Genomic comparisons of isolates supported the presence of a common contamination source in the shed and farm environments rather than multiple sporadic contamination events. This survey establishes a benchmark of Salmonella prevalence and types in the New Zealand egg production environment and provides a reference point for assessing the impact of changes to practices on Salmonella prevalence. HIGHLIGHTS

The influence of egg storage temperature on Salmonella contamination of eggs is a key consideration in determining storage and shelf life recommendations for eggs. In this study, experiments assessed the survival of Salmonella isolates on and in eggs at storage temperatures (15 and 22°C) currently used in New Zealand. Eggshell surfaces were inoculated with a cocktail of 10 Salmonella isolates comprising five serotypes, at a concentration of ∼106 CFU per egg (for determining shell surface survival) or ∼103 CFU per egg (for determining internalization). Additionally, a subset of eggs was artificially contaminated with sterile chicken feces prior to Salmonella inoculation. Inoculated eggs were incubated at 15 and 22°C. At 0, 21, and 35 days of incubation, eggshells were enumerated for Salmonella, and egg contents were tested for Salmonella presence or absence (yolk) or most probable number (albumen). Higher levels of Salmonella were recovered from eggshells following incubation at 15°C (31% relative humidity [RH]) compared with 22°C (45% RH) after both 21 and 35 days of incubation. Recoverable numbers of Salmonella from visibly clean eggshell surfaces declined over time at both storage temperatures and were at, or below, the limit of detection from eggs stored at 22°C and 45% RH for 35 days. A substantially higher concentration of viable Salmonella was recovered from eggshells that were experimentally contaminated with chicken feces compared with those without, particularly from eggs stored at 15°C and 31% RH for 35 days (2.38 log higher CFU from eggs containing feces). No Salmonella was detected in egg contents (albumen or yolk) at any incubation temperature or time point, regardless of the presence of feces. Findings emphasize the importance of current regulations that require eggs sold at retail to be visibly clean and will inform risk management decisions regarding egg storage times and temperatures with respect to Salmonella control in and on New Zealand eggs at retail. HIGHLIGHTS