Being the frugal that I am, I refused to discard a block of expensive gourmet cheese (which I consume little at a time just so that I don’t finish it too soon) despite it looking a little ‘odd’ and smelling a little ‘funny’ after few weeks. No prizes for guessing that I ended up with a good bout of food poisoning.
Well, that’s what you get when you eat contaminated food. A number of bacteria, virus and parasite contaminants are known to cause food poisoning with varying symptoms and onset. Most of them cause mild to moderate, self-limiting symptoms but some (such as C. botulinum, L. monocytogenes, E. coli) can sometimes result in fatal complications.
While many of us tend to blame the immediate prior meal as the cause of our food poisoning, it may not always be the case. It sometimes takes less than an hour to as long as a couple of days before the food poisoning symptoms develop, depending on the causative agents as well as how their toxins affect the intestines.
Table: Food poisoning causative agents, estimated times for symptoms to appear and its potential sources.
|Causative agent||Approximate time for symptoms to appear||Potential sources|
|S. aureus||30 mins – 6 hours||Food that are not cooked after handling (cold cuts, puddings, sandwiches).|
|B. cereus||10 – 16 hours||Leftover rice, cereals, vegetables, herbs and spices.|
|C. perfringens||6 – 24 hours||Cooked meat, stews, gravies which are improperly stored.|
|Norovirus||12 – 48 hours||Infected food handler. Contaminated leafy greens, fruits, shellfish.|
|Salmonella spp.||12 – 72 hours||Raw meat, poultry, eggs, unpasteurized milk, dairy products.|
|C. botulinum||12 – 72 hours||Improperly canned, smoked or fermented foods.|
|Vibrio spp.||1 – 4 days||Raw or undercooked shellfish, esp raw oysters.|
|enterotoxic: 1-2 days
enterohemorrhagic:3 – 4 days
|Raw or undercooked
beef, unpasteurized milk and juice, raw vegetables. Contaminated water.
|L. monocytogenes||1 – 4 weeks||Deli meats, unpasteurized milk, unwashed raw produce.|
|Cyclospora||1 – 14 days, May relapse over weeks to months||Raw fruits, vegetables and herbs.|
|Giardia lamblia||1 – 2 weeks||Infected food handler. Raw, ready-to-eat produce.|
The typical food poisoning symptoms include nausea, vomiting, diarrhoea, abdominal cramps and occasionally fever. However, enterohaemorrhagic strains of E. coli and Salmonella spp. can sometimes result in bloody diarrhoea, while Cyclospora food poisoning is often associated with bloating and gas. Some of these agents can also cause life threatening complications, for example L. monocytogenes can seed meningitis in immunocompromised persons while C.botulinum caused paralysis and subsequently death.
So, the next time you feel that something doesn’t look right, smell right; hasn’t been cooked or stored properly; or from an unreliable source, it is perhaps best to not eat it. Why take the risk?