Year 1 of a UK-wide survey of campylobacter contamination on fresh chickens at retail (February 2014 to February 2015)

Cumulative results for samples taken between February 2014 and February 2015  have now been published, including results presented by major retailer.

The results for the full year show:

• 19% of chickens tested positive for campylobacter within the highest band of contamination* 
• 73% of chickens tested positive for the presence of campylobacter
• 0.1% (five samples) of packaging tested positive at the highest band of contamination 
• 7% of packaging tested positive for the presence of campylobacter 

*More than 1,000 colony forming units per gram (>1,000 cfu/g). These units indicate the degree of contamination on each sample.

More than 4,000 samples of fresh whole chilled chickens and packaging have been tested. The chickens were bought from large UK retail outlets and smaller independent stores and butchers. The data shows variations between the retailers but none has met the target for reducing campylobacter (see table below). A full analysis of the survey results, including the publication of the raw data and the full year results for smaller supermarkets and shops, is being carried out by the FSA and will be published later in the summer.

Further details of the ongoing testing of chickens for campylobacter were also confirmed by the FSA. A new survey will start this summer and once again sample fresh whole chickens from all types of shops. Continued testing will help the FSA to measure the impact of the interventions now being introduced by the industry to tackle campylobacter.

The FSA has welcomed the publication of case studies by Marks & Spencer, Morrisons, the Co-op and Waitrose showing the results of their recently implemented campylobacter reduction plans. The data show significant decreases in the incidence of campylobacter on their raw whole chickens. The tests were carried out on more recent samples than those taken from the FSA survey samples, with some targeted to demonstrate the effect of particular interventions.
All results below are taken from the official statistics report for the survey which can be found at the link below. This report gives a full explanation of the results and background to the methodology.

The FSA advises that the data for individual retailers have to be interpreted carefully. Confidence intervals are given for each retailer and the ‘others’ category. These show the likely range of the results allowing for the number of samples taken.

The 95% confidence intervals means that we would expect the true prevalence to fall within the lower and upper confidence limits 95% of the time. A key factor in the width of this interval is the sample size. Those retailers with a relatively low market share have a low sample size and correspondingly wide confidence intervals.

The results show, taking the confidence intervals into account, that Tesco is the only one of the main retailers which has a lower incidence of chicken contaminated with campylobacter at the highest level (>1000 cfu/g), compared to the industry average.  Asda is the only main retailer which has a higher incidence of chicken that is contaminated by campylobacter at the highest level, compared to the industry average. However, the results suggest that over the period of the survey none of the retailers achieved the joint industry target for reducing campylobacter.

The results below are for the first two quarters and represent 1,995 samples of fresh whole chilled chickens. The packaging was also tested for most of these samples. Data show variations between retailers but none are meeting the end-of-production target for reducing campylobacter (see table below).

These results show:

• 18% of chickens tested positive for campylobacter above the highest level of contamination*
• 70% of chickens tested positive for the presence of campylobacter
• 6% of packaging tested positive for the presence of campylobacter with only one sample at the highest level of contamination (>1,000 cfu/g)

* Above 1,000 colony forming units per gram (>1,000 cfu/g). These units indicate the degree of contamination on each sample.

The overall figures show an increase in contamination from the first quarter to the second quarter. This is most likely due to the second quarter’s samples being taken during the summer months when an increase in campylobacter is often seen because of the warmer weather.

The FSA advises that the data for individual retailers have to be interpreted carefully. Confidence intervals are given for each retailer and the ‘others’ category. These show the likely range of the results allowing for the number of samples taken.

At this half-way stage in the survey the results show, taking the confidence intervals into account, that Tesco is the only one of the main retailers which has a lower incidence of chicken contaminated with campylobacter at the highest level (>1,000 cfu/g), compared to the industry average. Asda is the only main retailer which has a higher incidence of chicken that is contaminated by campylobacter at the highest level, compared to the industry average. However, the results suggest that none of the retailers is achieving the joint industry end-of-production target for reducing campylobacter.

*The ‘Others’ category includes supermarkets where the market share was deemed small using the 2010 Kantar data, ie Lidl, Aldi, Iceland, plus convenience stores, independents, butchers etc.

95% confidence intervals means that we would expect the true prevalence to fall within the lower and upper confidence limits 95% of the time.