Salmonella in chocolate?
You’ve probably heard of the recent salmonella recall for Kinder Surprise chocolates. It coincided with Easter, a time when chocolate consumption increases exponentially and young children are particularly partial to Kinder chocolates with their milky taste and the small toys that come with the chocolate treat.
There were over 150 infections across a number of European countries and one case was identified in the US. Most cases have been children under 10, with many of the infected having to be hospitalized. Prior to Easter, Ferrero Australia conducted a recall of several Kinder chocolate products.
Salmonella is more commonly associated with raw meats, eggs and dairy that have not been properly handled, processed, or temperature controlled. To have it in chocolate is uncommon, but not unheard of.
The strain linked to this outbreak was Monophasic Salmonella Typhimurium and it has been traced to infected buttermilk at a Ferrero Factory in Arlon, Belgium. However, recalls were issued in countries as far away as Australia and New Zealand due to Fererro having a production facility in Australia and the source at the time was unknown.
Salmonella is more commonly associated with raw meats, eggs, and dairy that have not been properly handled, processed, or temperature controlled. To have it in chocolate is uncommon but not unheard of.
Apart from Buttermilk, What Other Ingredients Could Contaminate Chocolate?
Nuts such as peanuts, almonds, and cashew nuts can be ingredients used in certain chocolate blended products. Nuts increase the risk of Salmonella in multi-ingredient food products. The fat-filled nuts in peanut butter is susceptible to Salmonella (birds love feeding on nuts) and there have been a number of recalls over the years.
The recent Hepatitis outbreaks in packed and frozen berries are another potential risk for chocolate manufacturers who add dried berries to their chocolate products – if the berry supply chain is compromised or not in control.
So, how does Salmonella end up in our day-to-day food products?
Where does Salmonella come from?
And how can it be controlled?
Salmonella is a pathogen. A pathogen is a micro organism that produces an enterotoxin that can cause a reaction in the human gastro-intestinal tract which subsequently enters the bloodstream. It causes Salmonellosis in humans. Salmonella lives in the intestinal tracts of animals, including birds. So basically, faecal contamination is the cause of Salmonella in foods.
As the bacteria multiply, they metabolise and cause toxins to be produced. It is these heat-stable toxins that can withstand processing controls. It is not the actual organism itself that causes the infection, but the toxin it leaves behind once they are left to grow and multiply.
The key to controlling pathogen contamination is to make sure that the organism is not transferred to raw materials. This can be difficult in some circumstances and there will always be some small contamination present. In the food industry, it is common practice to mitigate risk if you are unable to remove it completely. This is what a HACCP Plan does.
If the organism is present, it can have the opportunity to grow if the right conditions are present. This is generally, the right amount of food (your product containing protein, fat and, or sugars), the correct heat range (in this case around 37 degrees celsius or human body temperature) and water (moisture levels). If you can control these factors, you will prevent organism multiplication and toxin production. This is generally achieved with a combination of:
- refrigeration
- pH control and
- moisture control (water activity) depending on the product.
- In the Ferrero incident, the buttermilk had most likely been handled poorly post pasteurisation of the original raw milk. It had then probably been contaminated with the organism during processing, not well temperature-controlled and kept for too long, allowing the bug to grow and produce the toxin. Once the toxin was present, the heat treatment allowable for milk was no longer going to be effective to remove it before use in the final product, the chocolate.
Testing to mitigate against the risk of Salmonella
A statistically sound positive-release system of the raw material and the finished product should be in place to pick up any levels above specification limits in the raw material.
That limit being that Salmonella is not detected in 25ml x 5 samples across the batch.
In the fully transformed final product, Salmonella is not detected in 25gm x 5 samples across the batch.
