Last updated on 29 April 2004

Evaluating the growth and survival of salmonella on chicken at chilled storage temperatures

This research project aims to evaluate the growth and survival of salmonella on chicken at chilled storage temperatures.

Study duration: April 2003 to June 2003

Contractor: Camden and Chorleywood Food Research Association Group (CCFRA)

Project code: B12004

Contact: For any enquiries relating to this project please contact CST@foodstandards.gsi.gov.uk

Background

Raw meats, and particularly poultry products, are known to be contaminated with salmonella. An FSA survey (B18002 FSA 2003) has reported that 5.7% of poultry contains this organism. Whilst proper cooking should inactivate the organism prior to consumption, it is desirable to minimise the numbers present on raw poultry at point of sale. One way to achieve this is to use a low chill storage temperature, which will prevent the growth of salmonella, if present.

Whilst many chilled food products can be stored at temperatures up to a maximum of 8°C, current regulations [Poultry Meat, Farmed Game Bird Meat and Rabbit Meat (Hygiene and Inspection) Regulations 1995] state that chilled poultry must be stored at no more than 4°C.

The FSA wished to evaluate the potential effect of any derogations from this regulation.

Research Approach

In order to investigate if an increase in storage temperature would affect the survival and growth of salmonella on chicken, inoculated chicken was stored at 0, 4, 6, 8, 10 or 12°C and the growth of the inoculated organism monitored over time.

Results and findings

A FSA funded project was undertaken by CCFRA, to investigate the growth and survival of salmonella in poultry over a range of temperatures (0-12°C). The project findings will allow the FSA to advise on the possible derogation from the regulation to allow storage of poultry at 8°C and the effect that this would have on the growth and survival of salmonella.

A mixed cocktail of Salmonella enteritidis and Salmonella typhimurium were not able to grow on aerobically packed chicken thighs stored at 0, 4 or 6°C over a 15 day period. However, at 8, 10 or 12°C, significant (p <0.01) salmonella growth was achieved (2 - 3 log increase in numbers) within nine days.

Based on this data, it can be concluded that any changes to the current chill storage regulations for chicken that allowed storage to a maximum of 6°C would be unlikely to allow the growth of salmonella on chicken over a 15-day storage period under aerobic conditions. Any change in storage temperature to allow use of temperatures above 6°C may allow growth of any salmonella present.