Mayonnaise is an oil-in-water emulsion, which contains at least 65% oil, in which lecithin from egg yolk, in a proportion of 4 - 8% is used as an emulsifier. The taste of mayonnaise is given by ingredients such as salt, sugar, mustard (it also acts as an emulsifier) ‌‌and an organic acid (citric acid from lemon juice or acetic acid from vinegar).

For a little variation, mayonnaise can be prepared not only with sunflower oil, but also with oil from the seeds of other plants such as rapeseed, sesame, soybeans, corn, and pumpkin. In any case, do not use olive oil because mayonnaise will taste bitter.

Depending on the dish you are going to prepare, you can give the mayonnaise a different consistency. A larger amount of oil embedded in the yolk leads to a firmer mayonnaise.

Homemade mayonnaise

Because home-made mayonnaise is made from raw eggs, it may be contaminated with the pathogenic bacteria Salmonella. Unlike commercial products, it may not contain enough salt, acid and preservatives to counteract the growth of bacteria. To avoid being sick from mayonnaise you should:

• Prepare mayonnaise from eggs obtained from authorized sources

Authorized source means that the facilities where the eggs are obtained and sold meet the minimum standards of the responsible regulatory agency.

• Pasteurized eggs are a safe choice for home-made mayonnaise

If you don’t have access to eggs that are free from Salmonella, they recommend replacing raw eggs with pasteurized eggs in shell or pasteurized yolks. SafeConsume specialists has tested various recipes with raw and pasteurized eggs and found that there are no differences in taste between them.

• Immediately after preparation and until consumption, mayonnaise should be stored in refrigerated conditions (4°C)

The reason why mayonnaise should be kept refrigerated is that salmonellae do not multiply at refrigeration temperatures.

• Discard temperature abused dishes with mayonnaise, but learn to avoid food waste too

Mayonnaise or dishes with mayonnaise that has been on the table for more than 2 hours without being consumed should be discarded as room temperature favors bacteria multiplication. So, in order to avoid food waste, it is advisable to prepare mayonnaise and dishes with mayonnaise in small quantities, which should ensure its consumption at one or two meals.

• Follow a procedure that kills Salmonella

SafeConsume scientists has developed a procedure using acid to kill Salmonella in egg yolks. Read more here Is it possible to prepare mayonnaise at home and not put consumers at risk? - Safeconsume (en)

If you choose to flavor mayonnaise with essential oils of basil, thyme, sage, marjoram, oregano or season it with garlic, ginger, or turmeric, you will be better protected from the microorganisms that can make you sick, as most limit the growth of microorganisms (e.g. oregano essential oil at a concentration of 0.70%, citronella essential oil at a concentration of 0.1%).

Happy and safe winter holidays from SafeConsume!

Taking the SafeConsume advice, you eliminate or reduce the risk of getting ill!

Homemade mayonnaise


• SafeConsume papers supporting this message:

Inactivation of Salmonella strains in acidified broth and raw egg yolk as a function of pH and acid type by Line Nielsen and Susanne Knøchel. DOI: 10.1016/

Salmonella in eggs: From shopping to consumption-A review providing an evidence-based analysis of risk factors by Maria João Cardoso, Anca Ioana Nicolau, Daniela Borda, Line Nielsen, Rui Leandro Maia, Trond Møretrø, Vânaia Ferreira, Susanne Knøchel, Solveig Langsrud, Paula Teixeira DOI: 10.1111/1541-4337.12753

Occurrence of Salmonella spp. in eggs from backyard chicken flocks in Portugal and Romania - Results of a preliminary study by Vânia Ferreira, Maria João Cardoso, Rui Miguel Magalhães, Rui Leandro Maia, Corina Neagu, Loredana Dumitrascu, Anca Ioana Nicolau, Paula Teixeira DOI: 10.1016/j.foodcont.2020.107180

• Other papers supporting this message

Ingredients of mayonnaise: Future perspectives focusing on essential oils to reduce oxidation and microbial counts by Izabela Alves Gomes; Flávia dos Santos Gomes; Otniel Freitas-Silva; Janine Passos Lima da Silva.

Utilization of essential oils from citronella and geranium as natural preservative in mayonnaise by Ebtehal A. El-Kholany.