First prosecution in the UK involving whole genome sequencing when tracing a Salmonella outbreak results in guilty pleas

The long running case involving the 2021 Salmonella outbreak in the United Kingdom has been resolved by guilty pleas. The trial was to take place over some 6 weeks in the Bolton Crown Court in December. Sentencing will take place on 4.12.25.

RICHARD BARARCLOUGH KC leading TAYO DASAOLU instructed by Bolton Council prosecuted the case from the outset.

TAYTO GROUP LIMITED pleaded guilty to two counts (1) between September 2020 and August 2021 placed an unsafe food on the market in that food namely pork scratchings produced by them at their site in Westhoughton, Bolton was contaminated with Salmonella Infantis and whole Genome Sequencing of Salmonella isolates from the said pork scratchings showed that they were genetically related to isolates obtained in an outbreak of the Salmonella Infantis between September 2020 and July 2022 in England, Wales, Northern Ireland and Jersey (Article 14 of Regulation (EC) 178/2002 and Regulation 19 of the Food Safety and Hygiene (England) Regulations 2013) and (2) failing to ensure that food was protected against contamination likely to render food unfit for human consumption, injurious to health etc (Regulation 852/2004).

The pleas related to the period June to August 2021. The outbreak continued into 2022.

The United Kingdom Health Security Agency, Public Health Scotland, the Food Standards Agencies for England, Scotland, Wales, Northern Ireland and Bolton Council which is the local regulatory agency for the Bolton factory began to investigate an outbreak of Salmonella dating back to September 2020.

Expertise to be called in the case would have engaged food micro biology, epidemiology, environmental health, building pathology specialising in water systems and experts from the UK Agency Gastrointestinal Infections and Food Safety Division.

The distribution of cases was high in the South East, Wales, Yorkshire, West Midlands, the South West and North West. There was a number of cases in Scotland and one in Northern Ireland.

Samples were taken from a number of consumers who ate the product. They were linked with samples taken from the defendant’s factory where environmental health officers discovered a number of infrastructure defects.

The factory cooperated with the Agency in recalling the product and remedying the defective process.

Whole genome sequencing is a means of determining the DNA in all the genetic information of a substance. WGS enables the genomes of Salmonella bacteria to be analysed down to differences between individual DNA bases (Single Nucleotide Polymorphisms [SNPs]).

The microbiological investigation concluded “UKHSA is accredited …for whole genome sequencing and application of this methodology to microbiological characterisation of human and non-human sequence data. Phylogenetic analyses of the WGS data indicated very limited genetic diversity between outbreak cases and food and environmental samples, with all confirmed (according to the agreed case definition) outbreak cases’ isolates falling within a 5-SNP cluster and indicating that all isolates were highly likely to originate from a common source of contamination, with the majority being genetically indistinguishable. This provided strong microbiological evidence, in conjunction with the strong epidemiological evidence (in line with internationally accepted guidance on strength of evidence), that consumption of pork scratchings was associated with developing illness, with product manufactured by the Tayto company as the vehicle of infection”.

A fuller paper will follow the sentencing.