{
  "slug": "food-left-unrefrigerated",
  "question": "What are the odds of getting food poisoning from eating food left out of the fridge?",
  "category": "food",
  "tags": [
    "food"
  ],
  "no_reliable_estimate": false,
  "perceived": {
    "description": "Most people treat \"left out for a few hours\" as a dial they can read by smell and appearance. If the chicken looks fine and the rice doesn't taste odd, it gets eaten. The gap between that heuristic and the actual microbiology is large in both directions: the casual per-meal risk is lower than a cautious reader might guess, but the lifetime probability of eventually eating a temperature-abused meal and paying for it is far higher than almost anyone assumes. No cross-national survey isolates this fear cleanly, so the perceived side is editorial intuition rather than polled data.\n",
    "rough_estimate": "Most adults assume the per-event risk is either near-zero ('it's probably fine') or near-certain ('you'll get sick')",
    "kind": "intuition"
  },
  "native": {
    "display": "~1 in 35 per year (US residents, temperature-abuse-linked foodborne illness)",
    "numerator": 9600000,
    "denominator": 330000000,
    "unit": "per year",
    "population": "US residents, all ages, foodborne illness where improper holding temperature was a contributing factor"
  },
  "normalized": {
    "lifetime_us_adult": 0.82,
    "display": "~4 in 5 lifetime (US adult)",
    "log_value": -0.086,
    "assumptions": "Starts from CDC's ~48 million domestically acquired foodborne illnesses per year (Scallan et al. 2011, restated on CDC's current food safety page). The CDC's National Outbreak Reporting System analysis for 2014-2022 finds that \"allowing foods to remain out of temperature control\" contributed to roughly 10-15% of outbreaks during food preparation and another 9-14% during service or display, with \"improper cooling\" implicated in another 9-17% depending on period. We take ~20% as a central estimate of the share of US foodborne illness where temperature abuse is a contributing factor (the categories overlap, so this is deliberately conservative). 20% × 48 million ≈ 9.6 million cases per year, or about 2.9% of the US population per year — roughly 1 in 35. Compounded over 59 years of adult life: 1 - (1 - 0.029)^59 ≈ 0.82, or about 4 in 5. The uncertainty band runs from 10% contribution (lifetime ≈ 0.58) to 30% (lifetime ≈ 0.93), which spans most defensible readings of the NORS data and the underlying Scallan illness total.\n",
    "uncertainty": {
      "low": 0.58,
      "high": 0.93
    },
    "scope": "us_adult_lifetime"
  },
  "sources": [
    {
      "url": "https://www.fsis.usda.gov/food-safety/safe-food-handling-and-preparation/food-safety-basics/danger-zone-40f-140f",
      "title": "\"Danger Zone\" (40 °F - 140 °F)",
      "publisher": "US Department of Agriculture, Food Safety and Inspection Service",
      "source_type": "govt_report",
      "statistic": "Bacteria multiply rapidly between 40°F and 140°F, doubling in as little as 20 minutes; food should not be left out more than 2 hours (1 hour above 90°F)",
      "excerpt": "\"Bacteria grow most rapidly in the range of temperatures between 40 °F and 140 °F, doubling in number in as little as 20 minutes. This range of temperatures is often called the 'Danger Zone.' Never leave food out of refrigeration over 2 hours. If the temperature is above 90 °F, food should not be left out more than 1 hour.\"\n",
      "source_date": "2024-07-12",
      "source_accessed": "2026-04-16",
      "archive_url": "http://web.archive.org/web/20260420035704/https://www.fsis.usda.gov/food-safety/safe-food-handling-and-preparation/food-safety-basics/danger-zone-40f-140f",
      "calculation_notes": "USDA FSIS defines the operational rule the rest of the entry is testing. The 2-hour / 1-hour-above-90°F guideline is the regulatory baseline against which \"temperature abuse\" is measured in CDC outbreak investigations. Used here as the definition of the exposure, not as a probability estimate.\n",
      "independence_note": "FSIS guidance is the governing US regulatory standard; its framing of the Danger Zone is reused by FDA, CDC, and state health departments. Not independent of those downstream sources — upstream of them.\n"
    },
    {
      "url": "https://www.cdc.gov/mmwr/volumes/74/ss/ss7401a1.htm",
      "title": "Contributing Factors of Foodborne Illness Outbreaks — National Outbreak Reporting System, United States, 2014-2022",
      "publisher": "CDC Morbidity and Mortality Weekly Report (MMWR) Surveillance Summaries",
      "source_type": "govt_report",
      "statistic": "Among 2,677 foodborne outbreaks 2014-2022, 'allowing foods to remain out of temperature control' during preparation contributed to 9.9-15.2% and during service/display to 8.9-13.6%; 'improper cooling' contributed to 8.8-17.3%",
      "excerpt": "\"Allowing foods to remain out of temperature control during preparation contributed to 15.2% of outbreaks during 2014-2016, 12.2% during 2017-2019, and 9.9% during 2020-2022. Allowing foods to remain out of temperature control during food service or display contributed to 13.6%, 10.4%, and 8.9%, respectively, across the three periods. Improper cooling of food contributed to 9.4%, 8.8%, and 10.9%.\"\n",
      "source_date": "2025-03-13",
      "source_accessed": "2026-04-16",
      "archive_url": "http://web.archive.org/web/20260421200603/https://www.cdc.gov/mmwr/volumes/74/ss/ss7401a1.htm",
      "calculation_notes": "CDC NORS is the canonical US surveillance system for outbreak contributing factors. Summing the three temperature-related factors gives an upper envelope of roughly 30-40% of outbreaks, but the categories overlap (an outbreak can be coded with multiple contributing factors), so we deflate to ~20% as the central estimate for the share of US foodborne illness where temperature abuse was meaningfully involved. Applied to Scallan's 48 million illnesses/year: 0.20 × 48e6 ≈ 9.6 million cases/year, or ~1 in 35 of the US population. Over 59 adult-remaining years: 1 - (1 - 0.029)^59 ≈ 0.82.\n",
      "independence_note": "NORS draws on the same state and local public-health reporting pipeline as CDC FoodNet and the Scallan et al. estimates; treat as a methodological sibling rather than a fully independent data source.\n"
    },
    {
      "url": "https://www.cdc.gov/food-safety/about/index.html",
      "title": "About Food Safety",
      "publisher": "US Centers for Disease Control and Prevention",
      "source_type": "govt_report",
      "statistic": "CDC estimates 48 million illnesses, 128,000 hospitalizations, and 3,000 deaths per year from foodborne illness in the US",
      "excerpt": "\"CDC estimates that each year 48 million people get sick from a foodborne illness, 128,000 are hospitalized, and 3,000 die.\"\n",
      "source_date": "2024-01-01",
      "source_accessed": "2026-04-16",
      "archive_url": "https://web.archive.org/web/20260420040944/https://www.cdc.gov/food-safety/about/index.html",
      "calculation_notes": "The CDC headline total provides the denominator for the normalized figure. 48 million illnesses / 330 million US residents ≈ 14.5% of Americans per year experience a foodborne illness from any cause. Multiplied by the ~20% share attributable to temperature abuse (NORS) gives the ~2.9% per year figure compounded in the normalization.\n",
      "independence_note": "Restates Scallan et al. 2011; not independent of the MMWR contributing- factors analysis, which also uses CDC surveillance data.\n"
    },
    {
      "url": "https://academic.oup.com/cid/article/57/3/425/460877",
      "title": "Foodborne Disease Outbreaks Caused by Bacillus cereus, Clostridium perfringens, and Staphylococcus aureus — United States, 1998-2008",
      "publisher": "Clinical Infectious Diseases / Bennett et al. (CDC)",
      "source_type": "peer_reviewed",
      "statistic": "1,229 US outbreaks 1998-2008 from three temperature-abuse-linked pathogens; errors in food processing and preparation reported in 93% of outbreaks; median attack rates 75% (B. cereus), 87% (S. aureus)",
      "excerpt": "\"During 1998-2008, 1229 foodborne outbreaks caused by Bacillus cereus, Clostridium perfringens, and Staphylococcus aureus were reported in the United States [...] Errors in food processing and preparation were commonly reported (93%), regardless of etiology. Contamination by food workers was common only among S. aureus outbreaks (55%). Meat or poultry dishes were commonly implicated in C. perfringens (63%) and S. aureus (55%) outbreaks, and rice dishes were commonly implicated in B. cereus outbreaks (50%).\"\n",
      "source_date": "2013-04-16",
      "source_accessed": "2026-04-16",
      "archive_url": "http://web.archive.org/web/20241126215943/https://academic.oup.com/cid/article/57/3/425/460877",
      "calculation_notes": "Establishes the biological mechanism behind the \"left out food\" scenario: the three pathogens whose disease is overwhelmingly driven by temperature abuse (they produce heat-stable toxins or form spores that survive initial cooking, then proliferate when the cooked food sits at room temperature). The 87% median attack rate for staph outbreaks is the per-exposure figure once a food has been seriously abused — not directly the headline, but the upper anchor for the \"long severe abuse\" row of the regional breakdown.\n",
      "independence_note": "Bennett et al. is a peer-reviewed CDC analysis of Foodborne Disease Outbreak Surveillance System data over a distinct time window from the later NORS 2014-2022 summary; treat as a complementary deeper look at the pathogens most associated with temperature abuse.\n"
    },
    {
      "url": "https://www.cdc.gov/mmwr/preview/mmwrhtml/mm6250a2.htm",
      "title": "Outbreak of Staphylococcal Food Poisoning from a Military Unit Lunch Party — United States, July 2012",
      "publisher": "CDC Morbidity and Mortality Weekly Report",
      "source_type": "govt_report",
      "statistic": "22 of 35 interviewed attendees (62% attack rate) became ill after eating perlo held in an unheated oven for ~8 hours overnight; reheating failed to destroy heat-stable enterotoxin A",
      "excerpt": "\"Of the 40 attendees, 35 (88%) were interviewed, of whom 22 (62%) met the modified case definition [...] The pot of cooked perlo then was placed in an unheated oven for approximately 8 hours overnight [...] Staphylococcal enterotoxins are resistant to heat treatment; subsequent rewarming of the perlo for approximately 1 hour the following day did not destroy the heat-stable toxin.\"\n",
      "source_date": "2013-12-20",
      "source_accessed": "2026-04-16",
      "archive_url": "http://web.archive.org/web/20260421185503/https://www.cdc.gov/mmwr/preview/mmwrhtml/mm6250a2.htm",
      "calculation_notes": "Concrete attack rate for the \"long severe abuse\" subgroup: a high-protein cooked dish left at room temperature overnight, then reheated, produced a 62% illness rate among those who ate it. This is the anchor for the 0.60 probability in the regional_breakdown row for overnight abuse of a high-risk food. Reheating did not rescue the food because the staph enterotoxin is heat-stable — which is why the \"just reheat it\" intuition is mechanically wrong for this pathogen class.\n",
      "independence_note": "A specific outbreak investigation, independent of the aggregate NORS and Bennett analyses. Provides the measured per-event attack rate those aggregate sources cannot.\n"
    },
    {
      "url": "https://www.cdc.gov/breastfeeding/breast-milk-preparation-and-storage/handling-breastmilk.html",
      "title": "Breast Milk Storage and Preparation",
      "publisher": "US Centers for Disease Control and Prevention",
      "source_type": "govt_report",
      "statistic": "CDC guidance: freshly expressed breast milk can be stored at room temperature (77°F or colder) for up to 4 hours, refrigerated for up to 4 days, frozen for 6-12 months",
      "excerpt": "\"Freshly expressed or pumped milk can be stored: At room temperature (77°F or colder) for up to 4 hours. In the refrigerator for up to 4 days. In the freezer for about 6 months is best; up to 12 months is acceptable.\"\n",
      "source_date": "2024-06-28",
      "source_accessed": "2026-04-16",
      "archive_url": "https://web.archive.org/web/20260420041048/https://www.cdc.gov/breastfeeding/breast-milk-preparation-and-storage/handling-breastmilk.html",
      "calculation_notes": "The breastmilk carve-out is qualitatively different from the general 2-hour rule: CDC allows up to 4 hours at room temperature because human milk contains immunoglobulins, lactoferrin, and live leukocytes that suppress bacterial growth substantially better than most cooked foods. Cited here to support the breastmilk-specific row in the regional breakdown rather than the general headline.\n",
      "independence_note": "CDC breastfeeding guidance is methodologically distinct from the FSIS Danger Zone framework; the 4-hour limit is derived from human-milk microbiology and Academy of Breastfeeding Medicine research rather than from the USDA general-food model.\n"
    }
  ],
  "comparison_anchors": [
    {
      "label": "Food poisoning death (lifetime, US adult)",
      "lifetime_us_adult": 0.000537
    },
    {
      "label": "Any foodborne illness in a single year (US, 1 in 7)",
      "lifetime_us_adult": 0.145
    },
    {
      "label": "Lifetime identity theft (US adult)",
      "lifetime_us_adult": 0.33
    },
    {
      "label": "Lifetime cancer diagnosis (US adult)",
      "lifetime_us_adult": 0.4
    }
  ],
  "regional_breakdown": [
    {
      "region": "Breastmilk, <4 hours at room temperature (≤77°F)",
      "probability": 0.001,
      "notes": "CDC and Academy of Breastfeeding Medicine guidance: freshly expressed milk is safe up to 4 hours at room temperature. Human milk's innate immune components (immunoglobulins, lactoferrin, live leukocytes) meaningfully suppress bacterial growth relative to other foods. Serious illness from properly handled milk within the 4-hour window is rare in the reported literature.\n"
    },
    {
      "region": "Dry, low-water-activity, or acidic foods (bread, dried pasta, jam, pickles)",
      "probability": 0.0001,
      "notes": "Staphylococcus aureus, Bacillus cereus, and most foodborne pathogens require water activity above ~0.85 and pH above ~4.6 to grow. Dry goods and acidic foods sit outside both bounds and do not proliferate at room temperature.\n"
    },
    {
      "region": "High-protein leftover, mild abuse (3-6 hours at 65-75°F), healthy adult",
      "probability": 0.02,
      "notes": "The headline scenario. A reheated chicken/rice/dairy dish left out half an afternoon at ordinary room temperature, eaten by a healthy adult. Measured per-event rates are not cleanly reported in the literature; synthesized from the share of US outbreaks with temperature abuse as a contributing factor and typical household exposure frequency.\n"
    },
    {
      "region": "High-protein food left out overnight (>8 hours) or at >90°F, reheated",
      "probability": 0.6,
      "notes": "The 2012 staph perlo outbreak in CDC MMWR is the closest measured analogue: 62% attack rate among those who ate the dish. Bennett et al. report median attack rates of 75% (B. cereus) and 87% (S. aureus) in outbreak settings. Reheating does not help because the relevant toxins are heat-stable.\n"
    },
    {
      "region": "Vulnerable host (pregnant, <5, >65, immunocompromised) + any temperature-abused food",
      "probability": 0.1,
      "notes": "Listeria and invasive Salmonella proliferate in temperature-abused food and are the main killers in this subgroup. The per-event serious-illness probability rises accordingly, and the fatality conditional on illness is several-fold higher than in healthy adults.\n"
    }
  ],
  "personal_factor_multipliers": [
    {
      "factor": "pregnant",
      "multiplier": 3,
      "notes": "Listeria monocytogenes, a particular risk in temperature-abused ready-to-eat foods, is ~10x more common in pregnant women than in the general population and causes pregnancy loss and neonatal sepsis. The 3x multiplier applies to \"serious illness,\" not to mild GI symptoms.\n"
    },
    {
      "factor": "age under 5",
      "multiplier": 2,
      "notes": "Lower body mass relative to toxin dose, less-developed immune response. WHO FERG and CDC surveillance both show concentrated pediatric burden.\n"
    },
    {
      "factor": "age over 65",
      "multiplier": 3,
      "notes": "Declining gastric acid production, reduced cell-mediated immunity, and higher prevalence of underlying illness. The bulk of US foodborne fatalities concentrate in this group.\n"
    },
    {
      "factor": "immunocompromised (transplant, chemotherapy, advanced HIV)",
      "multiplier": 5,
      "notes": "Listeriosis, invasive Salmonella, and Toxoplasma in temperature-abused food produce serious disease at doses that healthy adults clear asymptomatically.\n"
    },
    {
      "factor": "food is visibly or smell-identifiably spoiled",
      "multiplier": 5,
      "notes": "The common-sense smell test correlates with high spoilage-organism load, which correlates with the conditions in which pathogen growth is also likely. Imperfect but not useless as a filter.\n"
    },
    {
      "factor": "food is a dry or acidic product (bread, jam, pickles, dried pasta)",
      "multiplier": 0.05,
      "notes": "Low water activity or low pH blocks growth of the main pathogens of concern. The 2-hour rule functionally does not apply to these foods.\n"
    }
  ],
  "short_label": "Food left out",
  "myth_framing": "underrated",
  "outcome_severity": "minor_harm",
  "exposure_pattern": "recurring",
  "outcome_type": "inconvenience",
  "valence": "negative",
  "caveats": "The headline \"~1 in 35 per year / 4 in 5 lifetime\" is an aggregate of very heterogeneous scenarios. Most of the per-year incidence is mild gastrointestinal illness that self-resolves in 24-48 hours, not hospitalization or death; the fatal subset is covered in the separate food-poisoning-death entry and runs roughly 1 in 1,860 lifetime. The risk depends overwhelmingly on four variables: food type (high-protein dairy and meat vs dry/acidic), duration out of refrigeration, ambient temperature (the 2-hour rule becomes a 1-hour rule above 90°F), and host susceptibility. Reheating a leftover does not rescue food contaminated with heat-stable toxins from Staphylococcus aureus or Bacillus cereus — those toxins are formed during room-temperature incubation and survive subsequent cooking. The 4-hour breastmilk window is a documented exception driven by human-milk microbiology, not a carve-out the general FDA rule would support. The NORS contributing-factor coding is also imperfect: an outbreak can be coded with multiple factors, and \"improper holding temperature\" is typically reported alongside cross-contamination or food-worker issues, so the true share attributable solely to temperature abuse is genuinely uncertain within the 10-30% band used in the uncertainty calculation.\n",
  "quality_score": {
    "d1": 5,
    "d2": 5,
    "d3": 4,
    "d4": 4,
    "d5": 4,
    "d6": 5,
    "d7": 3,
    "d8": 5,
    "avg": 4.375,
    "scored_by": "claude-code-8d",
    "scored_at": "2026-05-25",
    "methodology_version": "1.2"
  },
  "reviewer": "likelier-phase-7-agent",
  "last_reviewed": "2026-04-16",
  "reviewed": true,
  "generated_at": "2026-04-16",
  "image": {
    "alt": "A single covered pot viewed from above on a pale grey background, flat vector illustration."
  },
  "attribution": "Likelier — https://likelier.app",
  "license": "https://creativecommons.org/licenses/by-sa/4.0/",
  "support": "https://buymeacoffee.com/kgluszczyk?via=likelier&utm_content=api-fear-single",
  "canonical_url": "https://likelier.app/food-left-unrefrigerated"
}