Christchurch butchers handing out free cocktail sausages to children — a New Zealand tradition — have been linked to at least six cases of yersiniosis in kids under five-years-old.

Canterbury’s Medical Officer of Health, Dr Ramon Pink, says cocktail sausages (also known as cheerios or saveloys) should be heated before they are eaten and should not be offered cold to children at butcher’s shops or delicatessens.

The cocktail sausages were given to most of the children over the counter – a common practice which has been associated with outbreaks of salmonella and campylobacter in Christchurch in the past.

While cocktail sausages are cooked during their preparation they are not ready-to-eat foods. Further heating before eating is required to destroy any bacteria that may have contaminated them after they were made.