Buffet Food Safety: Temperature and Handling Studies
Buffets: Every Food Safety Challenge, All at Once
The study: Kirkland E, Green LR, Stone C, Reimann D, Nicholas D, Mason R, Frick R, Coleman S, Bushnell L, Blade H, Radke V, Selman C, and the EHS-Net Working Group. 2009. “Tomato handling practices in restaurants.” Journal of Food Protection 72(8):1692–1698. DOI 10.4315/0362-028X-72.8.1692. CDC’s Environmental Health Specialists Network observed tomato handling — including cold holding on buffet and salad bars — across restaurants in multiple states, measuring actual temperatures and holding times rather than relying on what managers reported.
Buffets concentrate the hazards: foods held for hours, handled by dozens of customers, at temperatures that drift. The EHS-Net team went into real restaurants with thermometers and observation checklists to document what actually happens — and the cold-holding numbers, including the buffet and salad bar lines, are the part every buffet operator should read twice.
What the thermometers found
Across the restaurants studied, cut tomatoes — a food the FDA treats as potentially hazardous once cut, because the interior of a tomato supports pathogen growth — sat at a median temperature of 42.0°F (5.6°C), with 52% of batches above the 41°F cold-holding limit. They’d been sitting for a median of 4.0 hours, with some batches held up to 12 hours. The failures weren’t confined to one corner of the operation: tomatoes held on buffet and salad bars were among the locations where the 41°F limit was exceeded, alongside walk-ins, reach-ins, and made-to-order stations. Cold holding failed everywhere it was attempted — including the display line customers serve themselves from, where there is no cook step downstream to correct it and the food goes straight from the pan to the plate.
The handling observations added the cross-contamination dimension. Only about half of cutting observations used produce-dedicated cutting boards, and glove use during ready-to-eat preparation was inconsistent — the study recorded 51% and 64% compliance on those practices respectively. On a buffet, where the same tongs travel between dishes in customers’ hands and sneeze guards are the only barrier between the food and the dining room, those upstream handling gaps arrive at the line pre-loaded.
Running a buffet safely
The findings point to non-negotiable controls, and they’re embarrassingly administrative. Calibrated holding equipment verified with thermometers — not “the light is on.” Shallow pans for even temperatures instead of deep ones with warm centers. Time tracking with discard at limits, because the study’s holding-time data shows product routinely sitting for most of a service shift. Dedicated serving utensils, replaced regularly, because utensils migrate between dishes in customers’ hands. Sneeze guards that actually guard. And a named person monitoring the line continuously — not setting it up and walking away.
Batch replenishment beats topping up: small fresh batches rather than refreshing old food with new, because every top-up resets the clock on paper while the oldest product underneath keeps aging. And for time-as-a-control — legitimate, in the Food Code, and sometimes the only option for a display without active holding — it requires the one thing struggling operations lack: rigorous time tracking with discard at the limit, written procedures, and documentation the health inspector can actually review. If you can’t guarantee the tracking, don’t claim the control.
The frustrating truth in the data is that almost every failure has a known, cheap, effective fix. The gap the EHS-Net observations keep exposing isn’t food science — it’s operational discipline. Assign the line a person, give them a thermometer and a log, and most of the findings disappear. The operations that do this don’t appear in outbreak reports.
Source: Kirkland E et al. and the EHS-Net Working Group. 2009. Tomato handling practices in restaurants. Journal of Food Protection 72(8):1692–1698.