Indian rojak sauce, a local Singapore peanut sauce, does not contain any seafood ingredient.
Yet, in 2009, Vibrio Parahaemolyticus - a seafood based bacterium - was linked to a massive food poisoning case in Singapore and even resulted in two fatalities. How did this bacterium cross contaminated with a peanut sauce which had no seafood ingredient?
This was one of the case study highlighted in the Food Hygiene Course I attended as part of the Workforce Skills Qualifications training as part of upgrading.
This course is compulsory for all food handlers in Singapore, even if the food handlers are service staff and are even part time staff. If, during investigation by the National Environment Agency in Singapore, establishments have food handlers who have not attended the course may face six demerit points per handler. Twelve demerit points results in immediate suspension of the establishment for two weeks.
In this course, I learnt that bacteria cross contamination is the major leading cause of massive food poisoning cases in Singapore. Compared to the other causes of food poisoning, bacteria formation is naked to the eye and can neither be tasted or smelt to prevent food poisoning.
For example, if yeast starts to form on the food, you can smell it. If it smells bad, you will throw it away. If molds start to grow on food, you can see the greenish colour alteration on the food and you will throw it away. Viruses can only survive on a living hosts. So that leaves bacteria, naked to the eye, tasteless and produce no smell.
Bacteria strive in humid temperatures between 4 Degrees Celsius and 60 Degrees Celsius. If each bacteria strain takes 30 minutes to multiple, within four hours, you could have a bacteria farm forming on your food be it cooked or uncooked.
Bacteria do not die at low temperatures and they just go to "sleep" at below 4 Degrees Celsius and will only be killed at high temperatures at above 60 Degrees Celsius. As such, cooked food posed to be a more fertile ground for bacteria formation as one is most likely to reheat it at more than 60 Degrees Celsius for next consumption.
Cross contamination of bacteria into food is also one of food poisoning cases in Singapore. This lead us back to the Indian Rojak Peanut Sauce food poisoning case.
Unfortunately, the exact source of the contamination of the April 2009 food poisoning case was not determined as the food remnants were all cleared, a similar incident in 1983 drew parallel with this April 2009 case. In the 1983 case, it was determined that some frozen cuttlefish was placed on the top level of the chiller for defrosting, while the Rojak sauce uncovered and placed at the bottom of the chiller. As such, the juices from the defrosting cuttlefish dripped down the Rojak sauce, causing cross contamination from a seafood to a non seafood dish.
As such, the conclusion for the April 2009 Rojak sauce food poisoning could have been caused by similar circumstances.
From this case study, while it is convenient to just place items in the chiller as one would like it, defrosting raw items should be placed at the bottom of the chiller and cooked food should be placed in covered containers at the top of the chiller to prevent cross contamination.
Prevention of cross contamination was also constant reminder during the course because cases of food poisoning in Singapore has been mainly due to cross contamination. In December 2007, several reported cases of food poisoning when they consumed a chocolate cake from outlets of a popular bakery. It was found that the cake samples had the Salmonella bacteria and the bacteria came from food handlers at the main factory.
Since food handlers provide food to the masses, a single source of contaminated food can spread to many instantly. Depending on the immunity of the affected individual, food poisoning could lead to fatality.
As such, it is important for food handlers to attend this training so as to remind oneself on the importance of reducing food contamination, especially those from cross contamination.