Pla-ra (Thai: ปลาร้า [plaː ráː], Lao: ປາແດກ) is a traditional Thai seasoning produced by fermenting fish with rice bran or roasted rice powder and salt fermented in a closed container for at least 6 months. Pla-ra is mostly used for northeastern food such as green papaya salad, which was listed at number 46 on world’s 50 most delicious dishes by CNN Go in 2011. Pla-ra has a very strong smell, which is considered unpleasant by some people. Its flavors are salty and sour, depending on the amount of salt put in and lactic acid resulting from fermentation process.
Pla-ra is said to have probably originated in Mekong Basin with other fermented fish products. It might have originated by accident when a batch of old or improperly prepared salted fish was found acceptable. Freshwater fermented fish products are best developed in the area from the west of the Annamite Mountains to lower Myanmar, where one of the main populations is Thai-Lao, who adopted the use of fermented fish from the south of the Yangtze River and developed it after they entered the Indo-Chinese peninsula.
Pla-ra is classified by its main ingredients. Pla-ra which is fermented with roasted rice powder will become yellow with a soft texture and distinctive smell. Mostly used as a paste, this type of Pla-ra is usually produced in central Thailand. This type of Pla-ra usually has striped snakehead fish or catfish as a main ingredient. The other type is Pla-ra fermented with rice bran. The product’s color is clear black with a stronger smell. The fish is softer and smaller. It is mostly found in northeastern part of Thailand as an ingredient, or as a raw food.
Pla-ra which uses fresh fish is called Pla-ra-sod. Its flavors are salty with a little bit sour from lactic acid. Pla-ra-lom uses dead fish with has an autolysis reaction until it has an unpleasant smell, or uses fish which is soaked in water for 12-24 hours until it is softer.
There are 2 phases for making Pla-ra. The first phase is to ferment fish with salt until it is softer, and the next phase is to ferment it with rice bran or roasted rice powder for its scent and flavor.
The process starts with cutting the fish into small pieces and fermenting it with salt. After 24 hours, the fish will be arranged into a container (mostly in a pot) until they are tightly packed and filed with salt water afterwards. The container will be sealed for 3 months After 3 months, a first stage Pla-ra will be mixed with rice bran or roasted rice powder. Then, it will be rearranged to the container and sealed for 2 months or more.
|Calcium||1505.06 mg %|
|Phosphorus||661.75 mg %|
|Vitamin B12||2.175±1.78 mg %|
224 microorganisms were found in Pla-ra, but after the classification, it was reduced to 98 microorganisms, classified as 4 families and 2 groups.
- Pediococcus divided as P. halophilus and Pediococcus sp.
- Staphylococcus divided as S. epidermidis and Staphylococcus
- Micrococcus sp.
- Bacillus divided as B. seebtilis and B. licheniformis
- No spore Gram-positive basillus
- Gram-negative basillus
P .halophilus is found the most when Pla-ra is fermented for 3-5 months. 90% of examples from the markets contain this bacteria, so it is concluded that P. halophilus has an important role in the fermenting process especially for Pla-ra’s unique taste and aroma. Pediococcus sp. also has a role for the taste and aroma, but not as much as P. halophilus. Staphylococcus, Micrococcus sp. and Bacillus act in protein degradation. 
Pla-ra is usually eaten raw or as a chilli fish sauce. This dish is made of roasted green pepper, garlic, shallot and boiled fish meat. All of these ingredients are ground together. Then boiled fermented fish liquid, fish sauce and lime juice are added to the mixture. It is used as a side dish for dipping vegetables or eaten with rice. Pla-ra can also be processed into a powder by baking it with some spices until they are all dry and grinding them all together.
When using Pla-ra as an ingredient for uncooked food, it is easily contaminated. An example is Nam phrik (Chilli fish sauce) which uses Pla-ra as an ingredient. Nam phrik is not cooked and is often kept for one or two meals. After a while, it will contain pathogens and have a high microorganism count. In some cases, Nam phrik had both E. coli and S. aureus present, but no pathogenic organisms. The reason is the acid from tamarind made the pH less than 4.6, which prevents the growth of most pathogens. Pla-ra before reheating is contaminated with S. aureus but the coliform is low and it is destroyed by cooking.
In a recent move by police and redevelopment workers to evict vendors from a market in the Khlong Toei District in Bangkok, the local vendors barricaded themselves. During the scuffles that ensued, the traders made "stink bombs" with thin plastic bags filled with pla ra and hurled them at the police. At noon of 1 February 2010 bags of excrement and pla ra were thrown into Thai Prime Minister Abhisit Vejjajiva's house.
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- Boon-Long, Narudom (1985). Development of Traditional Fermented Fish Product for Small Industries : Precessed development of Pla-ra from salt water fish. Bangkok, Thailand: Faculty of Agro-ind.,Kasetsart University.
- CNN, gostaff. "World's 50 best food".
- Prakash Tamang, Jyoti; Samuel, Delwen (2010). Prakash Tamang, Jyoti; Kailasapathy, Kasipathy, eds. Fermented Foods and Beverages of the World. London, England: CRC Press.
- Boon-Long, Phithakpol (1993). Lee, Cherl-Ho; Steinkraus, Keith H.; Reilly, P.J.Alan, eds. Fish Fermentation Technology. Seoul, Korea: United Nation University Press.
- ชมภูเพชร, พงษ์พันธุ์ (2003). รวยด้วยปลา. Bangkok, Thailand: Matichon.
- Bangkok Post - Stink bombs deployed in market riot
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