Salmonella in Chocolate
Although it is rare to have salmonella implicated in chocolate, chocolate products manufactured in England have been implicated as the most likely source of an outbreak of Salmonella Montevideo that affected 37 people in the UK from February to June 2006.
An outbreak in June 2006 prompted the implicated company to reveal their findings. In the findings, a leaking pipe was discovered that leaked waste water into the milk chocolate crumb mix. This mix is the base ingredient in several chocolate bar varieties.
On testing, the company revealed the presence of the rare strain of Salmonella, however they did not report these findings to food regulators or to instigate a public health recall.
It was not until the UK Food Standards Agency (FSA) published the results of their own outbreak investigation in June 2006 that the company disclosed their findings and withdrew seven products. This amounted to over a million chocolate bars from the UK market.
In defence, the manufacturer stated in an official media release that the reason they did not initially report their contamination findings was because the low levels of microorganisms found did not warrant such an action. This was a poor response and as part of due diligence should have acted on the results initially. In most developed countries, isolation of salmonella is notifiable.
A report released in July 2006 by the Advisory Committee on Microbiological Safety of Food (ACMSF), an expert committee that advises the FSA, responded with the statement that “the presence of Salmonella in ready-to- eat foods such as chocolate is unacceptable at any levelâ€. The company implicated was under such pressure that it released a further statement declaring that they have changed their protocols and that any products showing traces of Salmonella, regardless of how low the levels are, will be destroyed.
Although rare, the potential hazards associated with Salmonella and chocolate confectionery have long been known. The low moisture and high sugar content in chocolate increase its internal thermal resistance of bacteria and the high fat content provides protection for Salmonella against the low pH of stomach acid resulting in the low infective dose rate of the microorganism when consumed in chocolate.
in one study, heat treatments used to process the chocolate processing (conching) have been shown to be ineffective at inactivating some strains of salmonellae in high fat products. In one particular study, it was found that it took more than 1 hour to inactivate 90 percent of Salmonella Typhimurium in molten chocolate at 90C.
