April 19, 2009
Safe to eat?
Food poisoning can occur from improper handling and unhygienic serving and eating habits
By Tan Yi Hui
Singapore foodies must be feeling a little wary lately. Some of their long-time loves have made many people ill and even caused two deaths.
The culprits were not even raw food, which everyone knows can be dicey. They were cooked food - Indian rojak and steamboat.
Singapore's worst spate of food poisonings began at a Geylang Serai hawker centre earlier this month, when 100 customers of a stall selling Indian rojak sought treatment at hospitals. Some are still warded and two have died.
This was followed by news reports last week of 19 people who have fallen ill after eating at Ba Shu Ren Jia, a steamboat restaurant at 233, Lorong 9, Geylang.
While the full reports on how food poisoning at these two places came about are pending, many Singaporeans must be eyeing the food they love to eat with suspicion.
How could cooked food cause so much pain and suffering?
Indeed, experts told LifeStyle that food that has been prepared properly and cooked at temperatures close to 100 deg C should be safe to eat.
But there are blindspots. Poisoning can still occur in cooked food because of cross-contamination that results from careless handling when preparing, serving or eating.
Madam Koay Saw Lan, head of the Dietetics and Nutrition Services Department at Singapore General Hospital (SGH), says: 'Any food can be a vehicle for food-borne illness, but some are more likely than others.
'Proper food handling throughout the entire food production process from receiving and storage to serving is critical.'
Foods that are potentially hazardous include meat, poultry, fish, eggs and fresh produce, she says. 'These are frequently contaminated with food-borne pathogens which can spread to surfaces of equipment, to the hands of workers and to other foods. These foods are an excellent growth media for bacteria.'
Besides the main dish, experts advise diners to pay attention to sauces, chilli and other condiments that are placed at stalls for self-service.
Mr Edmund Yang, owner of hygiene consultancy Arise Services, says: 'Sometimes, it's the customers who are unhygienic. When people help themselves to these sauces, they scoop them directly onto their own plates, so the ladle comes into contact with their food and goes back into the sauce tub.'
A lot also depends on whether hawkers wash these ladles daily and how often the sauces are changed, he adds. To cut costs, some hawkers may refill the sauce tub without first pouring out the leftover sauce.
Generally, though, sauces are more resistant to decay than normal food. According to SGH's Madam Koay, they usually contain vinegar, sugar and salt, which are natural preservatives that make it too acidic for pathogens to thrive.
However, meat is more exposed to bacteria in the process of mincing, warns Dr Paul Chiew of the Agri-Food and Veterinary Authority (AVA). So always ensure that food with minced meat such as patties are thoroughly cooked.
As for the usual food poisoning suspects such as seafood, thorough cooking is most important, especially for young children, people with illnesses or pregnant women and older folks, as they are more susceptible to infections.
Dietician Ang Bixia from KK Women's and Children's Hospital says: 'Parents may feed soft-boiled eggs to young children. But under-cooked eggs may contain foodpoisoning bacteria. All eggs should be fully cooked before serving to children.'
She adds that pregnant women should avoid soft cheeses such as brie and camembert, and liver pates as they may be contaminated with bacteria that can cause miscarriage and stillbirth. Processed or hard cheese are safe.
But do not point the finger only at the food.
Hygiene expert Yang says: 'We always advise hawkers: Please use two chopping boards. Using the same board for cutting cooked and uncooked food and merely washing them with water in between is not good enough.
'Actually, food plays a very minimal role in food contamination and poisoning cases. It is the person who handles the food who's important.'
Before you bite...
Cooked poultry is left exposed at room temperature for several hours. They are often not reheated before serving to customers. The 'danger range' is between 40 and 60 deg C, as harmful bacteria multiply rapidly at such temperatures. So customers are actually ingesting 'bacteria-loaded' chicken.
Yong Tau Foo
Avoid fish and meat items which you suspect have been kept at ambient temperature for a prolonged period. These items are at greater risk of contamination and spoilage.
Even though all items are partially cooked and re-cooked again upon selection, watch out for poorly cooked raw items, especially seafood.
Most prata hawkers do not wear gloves during preparation. Observe the hawker, especially whether he washes his hands after using the toilet and after handling money. Make sure he handles cooked food with gloves or thongs when serving.
Make sure meat patties are grilled thoroughly, as the meat may be exposed to bacteria during mincing and preparation. Before eating, make sure the meat is not pink inside. Juices should run clear when the meat is pricked or sliced.
Always ensure these are cooked thoroughly. When eating shellfish such as oysters and cockles, you are consuming the whole organism, including the gut and its gut contents. As these are filter feeders, they may carry bacteria, viruses and biotoxins from the marine environment.
As the ingredients are usually not cooked and its preparation requires a lot of handling, food safety risks are higher if it is improperly handled.
Vegetables to be eaten raw or for making salads should be thoroughly washed, wrapped and stored at 4 deg C or below.
Steamboat/ Sichuan hotpot
Use separate plates and utensils for raw and cooked food. Mixing them may cause bacteria from the raw food to be transmitted to the cooked food. Do not add raw items into a pot while other food items are being cooked. You should add all items together or wait till the soup is boiling before eating.
Sichuan hotpots are unfriendly to those not used to spicy food. Spices stimulate acid production, sensitise the gut lining and increase contraction of the gut leading to pain, diarrhoea and vomiting, all of which are not necessarily the result of food poisoning
Sugar cane juice
Sugar cane stalks are porous and absorb whatever they touch. Although most drink-sellers now ensure their sugarcane stalks are not standing on dirty surfaces, look out for those who leave them on the floor.
Keeping germs away
Is it safe to leave cooked food exposed throughout the day, like some hawkers do?
Cooked food should never be left to stand at room temperature for more than two to four hours. As a rule of thumb, the 'danger range' is between 40 and 60 deg C, as harmful bacteria multiply rapidly at such temperatures.
If raw food that has gone a little stale is cooked properly, is it safe for consumption?
Decayed food is spoilt and therefore not safe to eat. Pathogens multiply very quickly, so cooking may not kill all of them.
Some people say it is okay to eat food that has dropped onto a dirty surface if it is picked up within five seconds. Is this true?
When food is dropped onto any surface, it has effectively become contaminated by coming into contact with the microbial environment of that surface, even for a few seconds.
At what temperature and for how long should food be reheated for safe consumption?
Reheat food to above 70 deg C for two minutes.
Some mothers and grannies feed boiled rice water to children suffering from diarrhoea. Does this folk remedy work?
Yes, it does to a certain extent. Dr Yap Chin Kong, a gastroenterologist, says it helps ease diarrhoea by preventing dehydration. He says: 'Rice water helps to replace what is lost from the body, such as water and salt. It acts as a supportive treatment.'
But rice water does not kill bacteria or viruses and one still has to consult a doctor and take antibiotics. This home remedy though is useful and cheap. Oral rehydration powder, which is similar in effect to rice water, costs about $2 for five sachets at pharmacies.
Sources: Agri-Food and Veterinary Authority, Singapore General Hospital, National Healthcare Group Polyclinics