Potato salad: cold potatoes, a heavy cup and a food-poisoning record

Potato salad starts from a cold boiled potato, and cooling does change it. In a small fasting test in 12 adults, boiled red potatoes eaten cold had a glycemic index of 56 against 89 eaten hot. We found no trial on potato salad itself, and the dressing brings its own weight. A US cup of 275 g with mayonnaise carries about 462 calories, 30.6 g fat and 492 mg sodium, worked out from the 100 g value of one survey recipe. A UK recipe comes out fattier at 239 calories and 20.6 g fat per 3.5 oz (100 g), with 37 mg sodium against 179 mg in the US entry. The risk that shows up most in the papers is food poisoning, where potato salad was the vehicle in several outbreak investigations.

The numbers, per 3.5 oz (100 g)

As people eat it, per 3.5 oz (100 g)

How much is actually in it

• US potato salad made with mayonnaise has 168 calories, 11.1 g fat, 15.8 g carbohydrate and 179 mg sodium per 3.5 oz (100 g). — FNDDS food code 71603010, Potato salad, made with mayonnaise Evidence E source
  Per 100 g: 168 calories, fat 11.14 g, carbohydrate 15.81 g, saturated fat 1.746 g, sodium 179 mg
• The UK composition table lists potato salad with mayonnaise at 239 calories and 20.6 g fat but only 37 mg sodium per 3.5 oz (100 g), a different recipe from the US entries. — CoFID 2021 code 15-874, Salad, potato, with mayonnaise Evidence E source
  Per 100 g: 239 calories, fat 20.6 g, carbohydrate 12.7 g, sodium 37 mg, potassium 258 mg

What a real portion looks like

• One cup of mayonnaise potato salad weighs 9.7 oz (275 g), which carries about 462 calories, 30.6 g fat and 492 mg sodium. — FNDDS portion 1 cup, 275 g Evidence E source
  1 cup 275 g: 462 calories, fat 30.6 g, carbohydrate 43.5 g, sodium 492 mg; unspecified quantity 138 g

What your body absorbs

• In 30 women with raised fasting glucose, 8.8 oz (250 g) of baked then chilled potatoes lowered glucose at 30 minutes by 9.2% and insulin by 22.6% versus boiled potatoes. — 30 females, mean BMI 32.8, fasting glucose 110.5 mg/dL, single test meals (n = 30) Evidence B source
  Glucose -4.8% and -9.2%, insulin -25.8% and -22.6%, GIP -41.1% and -37.6% at 15 and 30 min; glucose AUC not different
• In 13 healthy adults, cold-stored boiled potatoes with vinaigrette had a 43% lower glycemic index than freshly boiled potatoes. — 13 healthy subjects, Lund, test meals with 50 g available carbohydrate (n = 13) Evidence C source
  Resistant starch 3.3% to 5.2% after 24 h at 8 C; GI 96 vs 168 (-43%), insulin index 128 vs 185 (-31%)
• In 11 healthy adults, adding chicken, rapeseed oil and salad to mashed potato halved its glycemic index from 108 to 54. — 11 healthy subjects, single test meals (n = 11) Evidence B source
  GI 108 for mashed potato alone vs 54 with chicken breast, rapeseed oil and salad

What cooking and storage change

• In 12 adults, boiled red potatoes eaten cold had a glycemic index of 56 compared with 89 when eaten hot. — Study 2: 11 men and one woman aged 18 to 50 (n = 12) Evidence B source
  GI 56 cold boiled red vs 89 boiled red; baked Russet 77; instant mashed 88

What it does to your health

• In 410,701 older US adults followed 15.6 years, eating potatoes including potato salad 7 or more times a week was not linked to mortality after full adjustment. — 410,701 NIH-AARP participants aged 50-71 (n = 410701) Evidence C source
  Fully adjusted HR 1.02 (95% CI 0.97-1.06) for highest vs lowest potato intake

Safety, limits and interactions

• In a 2009 Connecticut reception outbreak, eating potato salad was strongly linked to Salmonella illness (OR 84.0) after bare-handed food handling. — 9 case-patients and 14 controls (n = 23) Evidence C source
  OR 84.0 for potato salad
• At a wedding with 111 guests, potato salad prepared in a sink where a sick worker had vomited was the vehicle of a gastroenteritis outbreak (OR 3.21). — 111 wedding guests, North Yorkshire (n = 111) Evidence C source
  Attack rate 50%; OR 3.21 (95% CI 1.78-5.78) for potato salad
• In a Quebec banquet outbreak that sickened 25 of 36 guests, potato salad was the implicated food and Bacillus cereus grew in its mayonnaise. — 36 banquet attendees (n = 36) Evidence C source
  70% attack rate; B. cereus 10^3 per gram in mayonnaise
• Among 57 Staphylococcus aureus outbreaks in southern Brazil in 2000-2002, potato salad with homemade mayonnaise was the vehicle in 11%. — 57 S. aureus foodborne outbreaks, Rio Grande do Sul, 5,991 exposed persons (n = 57 outbreaks) Evidence C source
  Potato salad with homemade mayonnaise 11% of vehicles; meats 35%, pastries 25%
• The FDA advises a two-hour limit at room temperature for foods needing refrigeration and a refrigerator at or below 40 F (4 C). — General population (home food handling) (n = -) Evidence E source
  No more than 2 hours at room temperature, refrigerator at or below 40 F

Who this works differently for

• In 24 adults with type 2 diabetes, a boiled then cooled potato dinner did not worsen glucose versus rice and lowered overnight glucose, though insulin was higher. — 24 males and females with T2DM, mean age 58, evening mixed meals (n = 24) Evidence B source
  No difference in postprandial glucose iAUC; higher insulin iAUC after cooled potato (95% CI 18.9-111.72 miU/mL); lower nocturnal glucose AUC for all potato meals
• In 19 adults at risk of type 2 diabetes, 300 g a day of cooked then chilled potatoes for 24 hours did not change insulin sensitivity versus control foods. — 19 adults with BMI 27.0-39.9, 24-hour intervention (n = 19) Evidence B source
  Matsuda index not different; lower fasting glucose (P = 0.043) and free fatty acids (P = 0.039); higher breath hydrogen
• When a homemade recipe calls for eggs that stay raw or undercooked when served, FDA advises shell eggs treated to destroy Salmonella or pasteurized egg products, and names children, older adults, pregnant women and people with weakened immune systems as at greater risk of severe illness. — US consumers, with children, older adults, pregnant women and people with weakened immune systems named as at greater risk Evidence E source
  Use shell eggs treated to destroy Salmonella or pasteurized egg products in raw or undercooked egg recipes

The bottom line

The chilled potato evidence is short and mostly single meals. In 30 women with raised fasting glucose, 8.8 oz (250 g) of baked then chilled potatoes gave 9.2% lower glucose and 22.6% lower insulin at 30 minutes than boiled potatoes, yet total glucose over the test did not differ. In 13 healthy adults, boiled potatoes stored cold for 24 hours in the study kitchen and dressed with vinegar had a glycemic index 43% lower than freshly boiled ones, 96 against 168, in a test not marked as randomized. Adding chicken, rapeseed oil and salad to mashed potato halved its glycemic index from 108 to 54 in 11 healthy adults, a mashed potato meal rather than a salad. Two trials in people with or near type 2 diabetes were more mixed. In 24 adults with type 2 diabetes, a boiled then cooled potato dinner raised glucose no more than basmati rice, while insulin after the meal was higher, and all three potato dinners gave lower overnight glucose than rice. In 19 adults with a BMI of 27 to 39.9 eating 11 oz (300 g) of chilled potatoes over 24 hours, insulin sensitivity did not differ from control foods, in a pilot that used a one-sided test. In 410,701 US adults aged 50 to 71 followed 15.6 years, eating potatoes seven or more times a week, potato salad among them, was not linked to death after full adjustment (HR 1.02, 95% CI 0.97 to 1.06). That is self-reported diet and covers potatoes in general. The caution with potato salad is handling. At a 2009 Connecticut reception, eating the potato salad carried odds of illness 84 times higher, a very wide estimate from 9 cases and 14 controls, where staff were seen touching ready-to-eat food bare-handed. At a North Yorkshire wedding, half of 111 guests fell ill after a potato salad was made in a sink where a sick worker had vomited, cleaned with chlorine disinfectant the night before (OR 3.21, 95% CI 1.78 to 5.78). At a Quebec party where 25 of 36 guests got gastroenteritis, the mayonnaise in the salad grew Bacillus cereus at 1,000 bacteria per gram, in a single outbreak put down to failed temperature control. Across 57 Staphylococcus aureus outbreaks in southern Brazil, potato salad with homemade mayonnaise was the vehicle in 11%. These outbreaks show how the salad goes wrong, not how to keep it safe. We hold no card on the temperature potato salad should be kept at or on how long it can stand out, so this page gives no such figure. The cold storage in the glycemic studies above was a lab step, not a storage rule. We also hold no card on homemade mayonnaise made with raw egg or on who is most at risk from these bacteria. We found no study on potato salad in pregnancy, in children, in kidney disease or with medicines.

Sources

1. pts-daily-r5-01 · food composition dataset
   Potato salad, made with mayonnaise (FNDDS 71603010): Energy 168 kcal, Total lipid 11.14 g, Carbohydrate 15.81 g, Fatty acids total saturated 1.746 g, Sodium 179 mg per 100 g
   USDA FNDDS 2021-2023, food code 71603010, FDC 2709543 · checked 2026-09-29
2. pts-daily-r5-02 · food composition dataset
   Salad, potato, with mayonnaise (CoFID 15-874): Energy 239 kcal, Fat 20.6 g, Carbohydrate 12.7 g, Sodium 37 mg, Potassium 258 mg per 100 g
   CoFID 2021, Public Health England, code 15-874 (OGL v3.0) · checked 2026-09-29
3. pts-daily-r5-03 · food portion dataset
   Potato salad, made with mayonnaise: 1 cup = 275 g; Quantity not specified = 138 g
   USDA FNDDS 2021-2023, food code 71603010, FDC 2709543 · checked 2026-09-29
4. pts-daily-r5-04 · RCT
   A quantity of 250 g of boiled (low RS) and baked then chilled (high RS) russet potatoes were consumed on two separate occasions. ... Results showed that the chilled potato elicited significant reductions at 15 and 30 min in glucose (4.8% and 9.2%), insulin (25.8% and 22.6%), and glucose-dependent insulinotropic peptide (GIP) (41.1% and 37.6%), respectively. The area under the curve for insulin and GIP were significantly lower after the chilled potato, but no differences were seen in glucose, glucagon-like peptide-1, and peptide YY, or overall subjective satiety.
   Nutrients, 2019 · checked 2026-09-29
5. pts-daily-r5-05 · clinical trial
   RESULTS: Cold storage of boiled potatoes increased resistant starch (RS) content significantly from 3.3 to 5.2% (starch basis). GI and II of cold potatoes added with vinegar (GI/II=96/128) were significantly reduced by 43 and 31%, respectively, compared with GI/II of freshly boiled potatoes (168/185). Furthermore, cold storage per se lowered II with 28% compared with the corresponding value for freshly boiled potatoes.
   Eur J Clin Nutr, 2005 · checked 2026-09-29
6. pts-daily-r5-09 · RCT
   The glycaemic index (GI) of pure mashed potato was 108, whereas combined with chicken breast, rapeseed oil and salad, it was only 54.
   Br J Nutr, 2011 · checked 2026-09-29
7. pts-daily-r5-06 · RCT
   Study 2: The glycemic index values of potatoes varied significantly, depending on the variety and cooking method used (P =.003) ranging from intermediate (boiled red potatoes consumed cold: 56) to moderately high (roasted California white potatoes: 72; baked US Russet potatoes: 77) to high (instant mashed potatoes: 88; boiled red potatoes: 89).
   J Am Diet Assoc, 2005 · checked 2026-09-29
8. pts-daily-r5-14 · cohort
   Eating baked, boiled, or mashed potatoes, French fries or potato salad seven or more times per week was associated with higher risk of overall mortality, in models adjusted only for age and sex (HR C4 vs C1 = 1.17, 95%CI = 1.13, 1.21). These results were attenuated in fully adjusted models (HR C4 vs C1 = 1.02, 95%CI = 0.97, 1.06).
   PLoS One, 2019 · checked 2026-09-29
9. pts-daily-r5-10 · case-control
   Nine case-patients and 14 control subjects were identified. Potato salad consumption was strongly associated with illness (odds ratio [OR] = 84.0). During the investigation, food service workers were observed to have bare-handed contact with ready-to-eat food.
   MMWR Morb Mortal Wkly Rep, 2010 · checked 2026-09-29
10. pts-daily-r5-11 · cohort
    The attack rate among the 111 guests was 50% and vomiting was a predominant feature. ... The sink was cleaned with a chlorine based disinfectant and used the next morning to prepare a potato salad, subsequently identified as the vehicle of infection in a cohort study of guests (odds ratio 3.21; CI 1.78-5.78, p = 0.0001).
    Commun Dis Rep CDR Rev, 1997 · checked 2026-09-29
11. pts-daily-r5-12 · cohort
    In the aftermath of a party, 70% (25 of 36) of attendees had gastroenteritis. ... The cohort study has shown that potato salad served at the party was significantly associated with the disease. The mayonnaise used to prepare the salad was analyzed and Bacillus cereus was isolated (10(3) bacteria per gram).
    Can J Public Health, 2002 · checked 2026-09-29
12. pts-daily-r5-13 · cross-sectional
    The main involved food vehicles were meats servings (35%), followed by pastries (25%), cheese (23%), pasta (11%) and potato salad with homemade mayonnaise (11%).
    Braz J Microbiol, 2013 · checked 2026-09-29
13. sf-left-r2-6 · agency advice
    Stick to the "two-hour rule" for leaving items needing refrigeration out at room temperature. ... Keep the refrigerator temperature at or below 40° F (4° C).
    US FDA, Are You Storing Food Safely? (consumer update) · checked 2026-10-08
14. pts-daily-r5-07 · RCT
    Dinner (40% EI) was consumed at 1800 h being either: 1) boiled potato (BOIL); 2) roasted potato (ROAST); 3) boiled potato cooled for 24 h (COOLED); or 4) basmati rice (CONTROL). ... No differences were detected in postprandial venous glucose area under the curve (iAUC) between CONTROL and all three potato conditions. Postprandial insulin iAUC was greater following COOLED compared to CONTROL (P = 0.003; 95% CI: 18.9-111.72 miU/mL). ... All potato meals resulted in lower nocturnal glucose AUC than CONTROL (P < 0.001; 95% CI 4.15-15.67 mmol/L x h).
    Clin Nutr, 2021 · checked 2026-09-29
15. pts-daily-r5-08 · RCT
    Nineteen adults with body mass index 27.0-39.9 kg m-2 consumed 300 g day-1 RS-enriched potatoes (approximately two potatoes; ~18 g RS) or CHO-based control foods, as part of lunch, evening and snack meals, over a 24-h period. ... RESULTS: Insulin sensitivity was not significantly different between the potato and control conditions.
    J Hum Nutr Diet, 2021 · checked 2026-09-29
16. sf-eggsafe-r6-potsalad-1 · agency advice
    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...Certain people are at greater risk for severe illness and include children, older adults, pregnant women, and people with weakened immune systems (such as transplant patients and individuals with HIV/AIDS, cancer, and diabetes).
    US Food and Drug Administration, What You Need to Know About Egg Safety · checked 2026-10-08