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Projects for Specific Foodborne Pathogens

Shiga-toxin producing Escherichia coli (STEC)

Microbiological survey of uncooked retail meat products (ESR Food, 2003-2005)

This project is a multi-year, countrywide survey of the prevalence and levels of Salmonella, shiga-toxin producing E. coli (STECs) and E. coli O157:H7 in retail beef, sheep, veal, and pork meat products. While significant data for Salmonella are available from the National Microbiological Database programme for all species other than pig meat, the data are from different locations in the supply chain and products are not necessarily comparable. Similarly, STEC and E. coli O157 data is available only for beef and veal products early in the supply chain. The objectives of this project are to define the relative proportionality of exposure and of the disease burden imposed by the various meat species through microbiological survey and by PFGE sub-typing isolates for comparison with human case isolates through the National Typing Database. The project will identify the most appropriate meat species for which to implement risk management options.

Comparison of quantitative methods for shiga-toxin producing E. coli (STECs) and E. coli O157:H7 in foods (ESR Food, 2004-2005)

The strategic requirement of NZFSA to reduce the level of foodborne illness in New Zealand requires a robust understanding of the proportionality of exposure to various pathogens from different food groups. Enumeration of pathogens is required for fully informed risk assessments. The NZFSA STEC Steering Group has requested an assessment of the technologies available (e.g. plating, MPN, real-time PCR) for quantitative detection and isolation of STEC and E. coli O157:H7. The goal of this project is to review the literature on quantitative technologies for STEC and E. coli O157; gather and evaluate current information from overseas diagnostic and research laboratories; identify equivalence where possible; compare the cost of available technologies; and recommend to NZFSA an appropriate method for all subsequent research initiatives.

Microbiological survey of imported and domestic pork (ESR Food, 2004-2005)

The strategic requirement of NZFSA to reduce the level of foodborne illness in New Zealand requires a robust understanding of the proportionality of exposure of various pathogens from different food groups, in this case pig meat from domestic and foreign sources. New Zealand imports approximately a third of its pig meat requirements. Salmonellosis is the second most frequently reported bacterial gastrointestinal illness in New Zealand. Overseas pig meat is considered a significant source of Salmonella exposure for consumers as is E. coli O157:H7, an emerging disease especially in terms of market access. The goal of this project is to carry out a pilot survey of uncooked imported and domestic pig meat prior to secondary processing for the presence of Salmonella and E. coli O157:H7, and presence/numbers of generic E. coli in order to answer questions of proportionality of exposure; to assess the likelihood of introducing novel and pathogenic serotypes into New Zealand; to provide a guide for evaluation of food safety programmes (FSP) for uncooked comminuted fermented meats (UCFM); and to provide a guide for development of the pork National Microbiological Database (NMD).

Temperature control at retail level (ESR Food, 2004-2005)

A number of quantitative risk assessments for major foodborne microbiological hazards currently under development by NZFSA require a better understanding of the handling of meat during retail processing and storage in order to better determine the extent of pathogen growth at different stages, and under different circumstances. The goal of this study is to acquire a better understanding of the adequacy of temperature control of meat (sheep and poultry) during transport between the slaughterhouse and retail outlet, and during retail processing and display.

Assessment of domestic food handling practices (ESR Food, 2004-2006)

A significant portion of foodborne illness is thought to be caused by unsafe food handling practices in the home. Data on the food handling practices of New Zealanders is limited, with the main sources being three postal and telephone surveys conducted in the 1990s. More accurate and better targetted information is needed to support risk management, particularly the development of risk models to assess potential interventions. A quantity of data is available from Australia, and although this may be useful in some areas are not be applicable to New Zealand. ESR will collate information on consumer food handling via direct measurements in homes and interviews with the public. Information gathered will include the temperature during transport from the retail outlet to the home, the temperature of domestic refrigerators, and room temperatures with respect to defrosting and handling. The potential for cross-contamination will be assessed through observation of the layout of food stored in refrigerators with particular emphasis on the storage of raw meat and poultry in relation to ready-to-eat foods, and microbiological analysis of food contact surfaces. Domestic handling will be simulated in the laboratory to provide quantitative information, especially in relation to transfer rates for bacteria on surfaces.

National typing database (ESR Food, 2003-2005)

A standardised, national, pulsed-field gel electrophoresis (PFGE) microbial sub-typing database is being implemented to allow more effective detection of clonal linkages between human case isolates and food/environmental isolates of Campylobacter, Salmonella, Shiga-toxigenic E. coli (STEC) and Listeria. The National Typing Database will be an important tool facilitating the identification of factors that, if controlled, should reduce the burden of human gastroenteritis in New Zealand. In addition, subsequent research directions will be identified that will enable better management the risks of food-borne disease. All NZFSA sponsored projects that isolate the aforementioned zoonotic hazards will be required to subtype isolates and submit the data to the National Typing Database. The aim of this continuing project is to provide food-specific input into the development of the National Typing Database though completion of PulseNet certification, participation in testing the pilot system, and validation of results from historical NZFSA and MoH projects against the new procedures.