Pla ra (Thai: ปลาร้า, pronounced [plāː ráː]) 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 six months. Pla ra is mostly used in northeastern food such as green papaya salad. 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 Thailand as an ingredient, or as a raw food.
Pla ra which uses fresh fish is called pla ra sot. 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 two 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 in a container (mostly a pot) until it is tightly packed and filled with salt water afterwards. The container will be sealed for three months After three months, a first stage pla ra will be mixed with rice bran or roasted rice powder. Then, it will be rearranged in the container and sealed for two months or more.
|Calcium||1505.06 mg %|
|Phosphorus||661.75 mg %|
|Vitamin B12||2.175±1.78 mg %|
Many species of bacteria have been found in pla ra:
- Assorted species of Pediococcus, primarily P. halophilus
- Assorted species of Staphylococcus, primarily S. epidermidis
- Assorted species of Micrococcus
- Bacillus subtilis and B. licheniformis
- Other, non-spore-forming gram-positive bacteria
- Other gram-negative bacteria
P. halophilus is found the most when pla ra is fermented for three to five months. A study found that ninety percent of samples from markets contain this species of bacterium, so it has been concluded that it has an important role in the fermenting process, especially for pla ra's taste and aroma. Other Pediococcus species also have a role in the taste and aroma, but not as much as P. halophilus. Species of Staphylococcus, Micrococcus, 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, shallots, 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 it is dry and the grinding it 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. On 1 February 2010 bags of excrement and pla ra were thrown into Thai Prime Minister Abhisit Vejjajiva's house.
- Phithakpol, Bulan (1985). Phase I : Food Handling at Village and Household Levels in Thailand. Bangkok, Thailand: The Institute of Food Research and Product Development, Kasetsart University.
- Boon-Long, Narudom (1985). Development of Traditional Fermented Fish Product for Small Industries: Precessed development of Pla-ra from salt water fish. Bangkok: Faculty of Agro-ind., Kasetsart University.
- 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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