Is mayonnaise safe during pregnancy?

It depends on the egg. No study has looked at mayonnaise and pregnancy directly, so the answer comes from food safety. Homemade mayonnaise and aioli made with raw egg keep turning up in Salmonella outbreaks: in a Sydney barbecue outbreak, raw egg mayonnaise in a Russian salad carried an adjusted odds ratio of 10.3 for illness, with a 95% interval from 1.79 to 59.5. The FDA tells pregnant women to avoid foods with raw or undercooked egg, including homemade dressings. Shop-bought US mayonnaise is a different product: it is acidified by law, and US rules require pasteurized egg products, the usual yolk ingredient of commercial mayonnaise, to be safe to eat without cooking.

Not for everyone. Homemade mayonnaise, aioli or dressing made with raw shell eggs is the version to skip in pregnancy, or to make with pasteurized eggs or pasteurized egg products, as the FDA advises.

What the studies found

There are no randomized trials, systematic reviews or cohort studies of mayonnaise in pregnancy. What exists is outbreak investigations in the general population, laboratory studies and regulation. That is weak evidence for an exact risk and good enough evidence for where the risk lives.

Outbreaks with raw-egg mayonnaise

Three outbreak investigations point at the same vehicle. At the Sydney barbecue, food made by an unregistered family business, raw egg mayonnaise in a Russian salad was the most likely primary source of Salmonella Typhimurium, with an adjusted odds ratio of 10.3 (95% interval 1.79 to 59.5). At a children's charity event in the UK, among 49 cases and 128 controls, eating egg mayonnaise bagels carried an odds ratio of 34.1 for diarrhea (95% interval 10.5 to 111.3), though no food was left to test. At a South Australian wedding with an attack rate of 20%, garlic aioli made with raw egg yolk carried an odds ratio of 5.4 (95% interval 1.6 to 18.1). These are odds among the people at each event, not the risk of a single serving, and each is one outbreak.

The wider picture fits. A meta-analysis of 35 case-control studies of sporadic salmonellosis named eating raw eggs among the most important risk factors, along with travel, predisposing conditions and eating in restaurants. Its pooled odds ratios are in the full text, which we could not read. A review of raw egg products names homemade raw-egg mayonnaise as one of the foods most often linked to Salmonella outbreaks.

Why shop-bought mayonnaise is different

Under the US standard of identity, mayonnaise must contain vinegar or lemon or lime juice as an acidifying ingredient, together with egg yolk ingredients. US egg product rules require pasteurized egg products to be edible without further preparation for safety. The mayonnaise standard itself does not require pasteurized egg. That protection comes from the egg product rules. A review of laboratory studies that added Salmonella, E. coli O157:H7 and Listeria to commercial mayonnaise and dressings found the pathogens died, and its author reads the absence of reported illness from commercial acidic dressings as evidence of their safety. That review is from 2000, the evidence is laboratory data plus absence of reports, and none of it was done in pregnancy.

Acid alone does not make a homemade batch safe. In a laboratory study of homemade raw-egg mayonnaise, lower temperatures reduced the antibacterial action of the acids, so Salmonella survived longer in the fridge. That is a laboratory result and not a reason to leave mayonnaise out of the fridge.

Who should be careful

Pregnant women, which is the point of the question. The FDA states that foodborne illness during pregnancy is serious and can lead to miscarriage, premature delivery, stillbirth or the death of a newborn. It lists foods containing raw or undercooked eggs, including certain homemade salad dressings, among the foods higher-risk people should avoid. When Salmonella does reach the uterus, which is rare, the published record is grim: in a review of 9 such cases, sepsis was described in 90%, spontaneous abortion in 60% and death of the fetus in 80%. Nine reported cases cannot say how often this happens.

Listeria is a second concern, and it is about ready-made food. In a UK survey of 3,249 sandwiches from hospitals and other health care settings, Listeria was more often found in sandwiches with salad, soft cheese or mayonnaise, and in prepacked ones from outside suppliers. The levels were mostly low, and the finding is about the sandwich as a whole.

Mayonnaise is made with egg yolk by its US definition, so it is an egg food. We found no evidence on mayonnaise alongside medicines or on egg allergy in pregnancy, so this page cannot say anything specific about either.

What expert bodies say

The FDA treats pregnancy as a high-risk state for foodborne illness and lists raw or undercooked egg foods, including homemade dressings such as Caesar dressing, among those to avoid. Its egg safety advice says recipes served with raw or undercooked eggs should use pasteurized shell eggs or pasteurized egg products. US federal rules set the acidifying ingredients of commercial mayonnaise and require pasteurized egg products to be safe to eat without further cooking. We found no expert body that warns against commercially made mayonnaise in pregnancy.

How we searched

What would change this answer

• Surveillance data on Salmonella in pregnancy broken down by the food that caused it. That would turn an inferred risk into a measured one.
• An outbreak traced to commercially made mayonnaise. None has been reported in the review we found, and one would change the advice on shop-bought jars.
• Any study that counts pregnancy outcomes after eating mayonnaise of either kind. We found none.

What mayonnaise contains, spoon by spoon, is on the mayonnaise page.

Sources

1. ev-mayp-01 · Observational data · retrospective cohort outbreak investigation · n = 87
   Microbiological evidence confirmed that a number of food items were contaminated with Salmonella Typhimurium 108/170, with the raw egg mayonnaise used in a Russian salad being the most likely primary food vehicle (adjusted odds ratio=10.3 [95% confidence interval 1.79-59.5]).
   
   Who: attendees of a privately catered community barbeque, Sydney, 2009; food prepared by an unregistered family business
   Effect: raw egg mayonnaise (Russian salad): adjusted OR 10.3 (95% CI 1.79 to 59.5); 71 of 87 met case definition, 18% hospitalized
   Certainty: Single outbreak; homemade raw-egg mayonnaise, not commercial.
   Foodborne Pathog Dis, 2011 · checked 2026-10-07 · we read the abstract
2. ev-mayp-02 · Observational data · unmatched case-control outbreak investigation · n = 177
   Risk factors for diarrhoea were eating egg mayonnaise bagels (OR=34.1, 95%CI 10.5 - 111.3) and drinking apple juice (OR=16.1, 95% CI 3.5 - 74.2).
   
   Who: attendees of a children's charity event, Hertsmere, UK, 2006; 49 cases and 128 controls
   Effect: egg mayonnaise bagels: OR 34.1 (95% CI 10.5 to 111.3)
   Certainty: No food samples left to confirm the vehicle; caterer-made filling.
   Euro Surveill, 2007 · checked 2026-10-07 · we read the abstract
3. ev-mayp-03 · Observational data · retrospective cohort outbreak investigation · n = not stated in the abstract
   There was a significant association between consumption of garlic aioli and illness (OR 5.4, 95% CI: 1.6, 18.1).
   
   Who: wedding reception attendees, South Australia, 2009; attack rate 20%
   Effect: garlic aioli: OR 5.4 (95% CI 1.6 to 18.1); Salmonella Typhimurium PT 44 in stool and aioli
   Certainty: Aioli is a raw-egg emulsion like homemade mayonnaise; the eggs themselves tested negative.
   Commun Dis Intell Q Rep, 2011 · checked 2026-10-07 · we read the abstract
4. ev-mayp-04 · Observational data · systematic review and meta-analysis of case-control studies · n = 35 studies
   Results suggested that travel, predisposing factors, eating raw eggs, and eating in restaurants were the most important risk factors for salmonellosis.
   
   Who: people with sporadic salmonellosis and controls in published case-control studies
   Effect: raw egg consumption a leading pooled risk factor with travel, predisposing conditions and eating in restaurants; pooled ORs not given in the abstract
   Certainty: Observational; pooled ORs only in the full text, not read (not in PMC).
   Epidemiol Infect, 2012 · checked 2026-10-07 · we read the abstract
5. ev-mayp-05 · Laboratory or animal data · case series · n = 9 cases
   Indeed, sepsis, spontaneous abortions, and fatal outcomes for fetuses were described in 90, 60, and 80% of the cases, respectively.
   
   Who: pregnant women with intrauterine infection by nontyphoidal Salmonella, cases published 1966 to 2018
   Effect: sepsis 90%, spontaneous abortion 60%, fatal fetal outcome 80%; all mothers recovered on antibiotics
   Certainty: Case series (level D pending Roman's decision); rare event, reporting bias toward severe cases; not about how often Salmonella reaches the uterus.
   Journal of Maternal-Fetal and Neonatal Medicine, 2021, Intrauterine infection caused by nontyphoidal Salmonella: a literature review · checked 2026-10-07 · we read the abstract
6. ev-mayp-06 · Position of an expert body · agency consumer guidance · n = —
   Foodborne illness during pregnancy is serious and can lead to miscarriage, premature delivery, stillbirth, sickness, or the death of a newborn baby.
   
   Who: pregnant women and their unborn babies
   Effect: pregnancy named as a high-risk state for foodborne illness
   Certainty: General statement about foodborne illness, not about mayonnaise.
   FDA, People at Risk of Foodborne Illness · checked 2026-10-07 · we read the section
7. ev-mayp-07 · Position of an expert body · agency consumer guidance · n = —
   Raw or undercooked eggs or foods containing raw or undercooked eggs, including certain homemade salad dressings (such as Caesar salad dressing), homemade cookie dough and cake batters, and homemade eggnog.
   
   Who: people at higher risk of foodborne illness, including pregnant women
   Effect: avoid raw or undercooked egg foods, including homemade dressings
   Certainty: Names Caesar dressing, not mayonnaise; homemade mayonnaise is the same raw-egg emulsion.
   FDA, People at Risk of Foodborne Illness (Foods to Avoid) · checked 2026-10-07 · we read the section
8. ev-mayp-08 · Position of an expert body · agency consumer guidance · n = —
   For recipes that call for eggs that are raw or undercooked when the dish is served — like Caesar salad dressing and homemade ice cream — use either shell eggs that have been treated to destroy Salmonella, by pasteurization or another approved method, or pasteurized egg products.
   
   Who: US consumers; pregnant women named among those at greater risk
   Effect: use pasteurized eggs or egg products for raw-egg dishes
   Certainty: The practical fix for homemade mayonnaise in pregnancy.
   FDA, What You Need to Know About Egg Safety · checked 2026-10-07 · we read the section
9. ev-mayp-09 · Position of an expert body · federal regulation · n = —
   Mayonnaise is the emulsified semisolid food prepared from vegetable oil(s), one or both of the acidifying ingredients specified in paragraph (b) of this section, and one or more of the egg yolk-containing ingredients specified in paragraph (c) of this section.
   
   Who: —
   Effect: vinegar or lemon/lime juice at no less than 2.5% acidity; liquid, frozen or dried egg yolk or whole egg ingredients
   Certainty: Standard of identity for US commercial mayonnaise; it does not by itself mandate pasteurization.
   21 CFR 169.140 Mayonnaise (FDA standard of identity) · checked 2026-10-07 · we read the section
10. ev-mayp-10 · Position of an expert body · federal regulation · n = —
    Pasteurized egg products must be produced to be edible without additional preparation to achieve food safety and may receive additional preparation for palatability or aesthetic, epicurean, gastronomic, or culinary purposes.
    
    Who: —
    Effect: pasteurized egg products edible without additional preparation for safety
    Certainty: Applies to egg products made under USDA inspection, the yolk ingredients of commercial mayonnaise.
    9 CFR 590.570 Control of pathogens in pasteurized egg products (USDA FSIS) · checked 2026-10-07 · we read the section
11. ev-mayp-11 · Laboratory or animal data · narrative review with statistical analysis of challenge studies · n = not stated in the abstract
    The absence of reports of foodborne illness associated directly with the consumption of commercially prepared acidic dressings and sauces is evidence of their safety.
    
    Who: commercial US mayonnaise, dressings and sauces inoculated with pathogens (laboratory studies)
    Effect: pathogens die; acetic acid pH the key factor; highest target pH 4.4, below the inhibitory pH 4.5
    Certainty: Laboratory data and absence of reports; author from the dressings sector context, published 2000.
    Journal of Food Protection, 2000, Microbiological safety of mayonnaise, salad dressings, and sauces produced in the United States: a review · checked 2026-10-07 · we read the abstract
12. ev-mayp-12 · Laboratory or animal data · in vitro challenge study · n = —
    This study showed that lower temperatures reduce the antibacterial activity of the organic acids, which allowed Salmonella to survive at low pH for longer.
    
    Who: homemade raw egg mayonnaise and peptone water inoculated with Salmonella Typhimurium at pH 4.2 to 4.6 and 4, 23 and 37 C
    Effect: at 4 C Salmonella recovered after 10 days even at pH 4.2; at 23 C no growth or recovery at pH 4.2 and 4.4 after 24 h
    Certainty: Laboratory only; room-temperature holding is not general food-safety advice.
    Pathogens, 2019, The Combined Effect of pH and Temperature on the Survival of Salmonella enterica Serovar Typhimurium and Implications for the Preparation of Raw Egg Mayonnaise · checked 2026-10-07 · we read the fulltext
13. ev-mayp-13 · Laboratory or animal data · narrative review · n = —
    Within raw egg products, homemade mayonnaise prepared with raw eggs is one of the most common foods linked to salmonellosis outbreaks [23].
    
    Who: raw egg products, outbreak and laboratory literature
    Effect: homemade raw-egg mayonnaise a common outbreak vehicle; factory-made mayonnaise uses pasteurized eggs
    Certainty: Narrative review; the factory-made statement is attributed to an earlier review (Smittle).
    Pathogens, 2016, A Review of Temperature, pH, and Other Factors that Influence the Survival of Salmonella in Mayonnaise and Other Raw Egg Products · checked 2026-10-07 · we read the fulltext
14. ev-mayp-14 · Observational data · cross-sectional microbiological survey · n = 3,249 samples
    The presence of Listeria spp. and L. monocytogenes also was associated with sandwiches that (i) were supplied from outside the establishment, (ii) were prepacked, (iii) had a main sandwich filling of poultry meat, or (iv) contained salad ingredients, soft cheese, and/or mayonnaise.
    
    Who: sandwiches from UK hospitals and other health care establishments, 2005 to 2006
    Effect: L. monocytogenes in 2.7% of samples (88), mostly below 10 CFU/g; more frequent in sandwiches with salad, soft cheese and/or mayonnaise
    Certainty: About ready-made sandwiches as a whole, not mayonnaise alone; levels mostly low.
    J Food Prot, 2008 · checked 2026-10-07 · we read the abstract