How to know if idli batter is spoilt? 

In this brief guide, we are going to answer the question “How to know if the idli batter is spoiled”, discuss the different methods of identifying the spoiled idli, and the potential side effects of eating spoiled idli batter.

How to know if idli batter is spoilt?

To know if idli batter is spoiled, you should be able to identify possible signs of spoilage. In general, by analyzing the sensory properties of the idli batter, it is possible to verify if the batter is spoiled (1,2,3,4).

In terms of the smell, the generation of off-odor, such as rancid, putrid, extremely sour and alcoholic are possible signs of spoilage. Changes in the texture, such as phase separation, formation of a watery consistency are possible evidence regarding the texture.

Change in the color, production of bubbles on the surface, generation of pigments or mold growth (fuzzy colonies) are visible signs of spoilage, while the generation of gas (noticeable by the bloating of the package), formation of a slimy surface can also characterize spoilage of idli batter.

If you suspect that the idli batter is spoiled, do not try to taste it. It is safer to discard it. Consuming spoiled dosa batter can lead to foodborne illnesses.

What are the risks of eating spoiled idli batter?

The risks of eating spoiled idli batter are of experiencing a foodborne illness. Although the fermentation process of producing idli batter and other fermented cereal foods from India, such as dosa batter, are known to contain probiotic bacteria able to inhibit the growth of pathogenic bacteria (5), these foods are susceptible to spoilage, when not properly prepared or stored (3).

If you eat spoiled dosa batter, then you might usually get foodborne illnesses (3). The possible symptoms are nausea, vomiting, abdominal pain, stomach cramps, diarrhea, and headache.

If the symptoms get worse, then it is highly recommended to see a doctor immediately. 

Unhygienic conditions to prepare idli batter and contaminated grains can lead to foodborne illnesses. A study showed that many food items sold in India contained a high number of these pathogens, including dosa batter.

In the study analyzing the microbial contamination of street food in India, Bacillus spp., Staphylococcus spp., Enterobacteriaceae and Alcaligenes spp. Bacillus cereus were found in 17% of the samples, Clostridium perfringens were found in 1% of the samples, Staphylococcus aureus were found in 3% of the samples and Vibrio metchnikovii were found in 2% of the food samples (3).

What is the shelf life of idli batter?

According to studies, the shelf life of idli batter is about 5–7 days under refrigeration temperature (4–8°C) (6). However, it depends on the ingredients.

The idli batter can be added with essential oils and preservatives, which effectively extend the shelf life. In a study, by using selective strains of yeasts and applying mustard oil with antibiotic effect, the shelf life of idli batter could be increased to 30 days at 4°C.

Studies also report the development of fresh ready to cook idli batter packed in commercial PP nanocomposite multi-layered packaging film, which is a high oxygen barrier packaging. This product had a shelf life of 33 hours at room temperature (7).

In addition, it is reported that when idli batter is steamed in banana turmeric or jackfruit leaves, they have a much longer shelf life and were used traditionally for long trips (1).

How to make and store Idli safely?

To make idli safely, you should follow good and hygienic practices regarding personal practices and cooking practices.

Wash your hands and all the utensils properly with running water and soap, do not use cupboards and knives or containers that were used to prepare other foods. Check the ingredients to be used: if you notice any sign of spoilage or insect infestation, do not use them.

To prepare idli batter, follow the steps (1):

  • Wash the ingredients and use clean water to prepare the idli batter
  • Soak rice and split and peeled black gram (beans) is soaked in water in a ratio of 3:1. 
  • Ground separately black gram to a fine texture and rice to a coarse texture and mix them together with salt, and allow to ferment overnight
  • Store the fermented idli batter in a airtight container in the refrigerator and use it within 7 days or cook it
  • To cook idli batter, steam the fermented batter in molds to give a round, leavened, soft, and spongy product. Add spices, following your personal preferences


In this brief article, we answered the question “How to know if the idli batter is spoiled”, discussed the different methods of identifying the spoiled idli, and the potential side effects of eating spoiled idli batter.


  1. Prakash, Jamuna. Safety of fermented cereals and legumes. Regulating safety of traditional and ethnic foods. Academic Press, 2016. 283-310.  
  2. Cook, Frederick K., and Billie L. Johnson. Microbiological spoilage of cereal products. Compendium of the microbiological spoilage of foods and beverages, 2009, 223-244.  
  3. Saxena, Gargi, and Priyanka Saini. Hygiene and Sanitary Practices of Street Food Vendors: A Review. IJIRSET, 2022, 11,12.
  4. Rawat, Seema. Food Spoilage: Microorganisms and their prevention. Asian j plant sci Res, 2015, 5, 47-56.
  5. Ramachandran, Chelliah, Ramakrishnan Sudha Rani, and Antony Usha. Evaluation of safety, antimicrobial activity and probiotic properties of Escherichia coli Nissle 1917 isolated from Idli batter. J. Biotechnol, 2016, 11, 7.
  6. Sonawane, Sachin K., Vrinda R. Kandu, and Sonal Patil. An Overview on characterization and value addition of traditional Indian fermented food: idli. Am J Clin Nutr, 2019, 2, 1-6.
  7. Gaikwad, P. S., et al. Development of high oxygen barrier multi-layered packaging film for shelf life extension of Ready-To-Cook (RTC) idli batter. Int Res J Pure Appl Chem, 2020, 21, 13-27.

Was this helpful?

Thanks for your feedback!