Cook-Chill Offers Powerful Production

By Larissa Doucette and Carol Meres Kroskey, Contributing Editor

Cook-chill production may seem to be a complex undertaking, yet main equipment pieces can occupy just 500-sq.-ft. of space while still producing thousands of meals. FE&S spoke to four operators about how their cook-chill equipment has been laid out to ensure maximum productivity.

Today, cook-chill production can be used in almost any foodservice operation, but such systems have traditionally shined in higher-volume facilities. Capable of pumping out thousands of meals each day, cook-chill equipment allows operators to produce to inventory rather than service, thus building up food banks while lowering the number of employees and production hours required to supply a program. Nonetheless, the main equipment of a cook-chill system can often be installed in a remarkably small space.

Occupying only about 500-sq.-ft. within a 37,000-sq.-ft. production facility, cook-chill equipment at Notre Dame University is used to prepare about 24,000 meals a day. Most of the facility's cook-chill output goes to Notre Dame's two on-campus residence dining halls, though some 15 other outlets are also served by this central production kitchen, said John Glon, general manager of the university's foodservice support facility.

Cook-chill facilities typically include equipment such as jacketed kettles, pumping stations, tumble chillers, ice builders, cook-chill tanks, blast chillers and, of course, large walk-in refrigerators and freezers. The kettles are used to cook products, which are then transferred into bags via the pumping station. Filled bags are loaded into tumble chillers that chill products with ice cold water. Cook-chill tanks allow operators to cook such diverse items as roasts or rice and follow the cooking process with an ice water bath that chills products down.

Notre Dame's central production facility is equipped with two steam-jacketed kettles outfitted with agitators that automatically stir products. One kettle holds 160 gals. and the other 100 gals. Glon noted that it is important to use a correctly sized kettle since if a unit is heated while less than half-full, its contents will burn. If a kettle is too big, on the other hand, overproduction can occur, even if a kettle is only half-full.

When Notre Dame's cook-chill facility first opened in 1997, it was equipped with two 150-gal. kettles, Glon said. Two years ago, however, foodservice replaced one of the units with the 100-gal. kettle. "We put in the smaller piece so that we could make smaller batches and keep our production moving," he explained.

Kettles used for cook-chill production usually have a jacket so that cold water can be circulated to chill their contents. "We don't normally have to use the pre-chill option on our kettles," Glon noted. "However, if we are adding ingredients for a pasta salad or potato salad, for example, we fill the jackets with cold water to chill these delicate main ingredients more quickly. Also, cold-water jackets maintain temperatures in a kettle as we add cold ingredients to a composed salad so we don't have to run the batch through the chilling phase."

Claudio Tarallo, manager of foodservice operations at New York Weill Cornell Medical Center, New York, said he does not use the cold-water circulation feature on his 200-gal. and 100-gal. kettles. Instead, he pumps products into bags right away and transfers them to a tumble chiller.

Once a product has been kettle-cooked, it is pumped into holding bags by hooking up a mobile pumping station to a kettle. Tarallo said his facility only has one functioning pump station, but that repairing a second pump that broke down a while ago is under consideration, as his department may be called on to extend its production capabilities to other facilities in the healthcare system or become a central commissary for all its hospitals.

The small space occupied by Notre Dame's cook-chill system makes it convenient to transfer product-filled bags into a tumble chiller. Here, the tumble chiller can hold 200 gals. of bagged products. "When we built the facility, we were looking at a strict budget and a limited amount of space for cook-chill equipment, so we decided to stagger the chilling process instead of getting two tumble chillers. Also, if we had a second chiller we would overproduce," explained Glon.

During operation, cold water is pumped into Notre Dame's tumble chiller from an ice builder that is remotely located. The ice builder has a reservoir of water that has a temperature less than 0°F. Metal agitating paddles keep the water constantly moving, so that it does not freeze.

The foodservice department at New York Weill Cornell also houses its cook-chill equipment in a small area, about 800-sq.-ft., according to Tarallo. The tumble chiller here, which is situated about 2 ft. from the pump, holds about 100 gals. of ice cold water and can chill between 100 and 120 2-lb. bags at one time without compromising food quality or safety, he said.

Cook-chill tanks are also widely considered to be vital to the operation of most larger cook-chill facilities and Weill Cornell utilizes a tank that can hold 300 lbs. of meat products or 50 bags (200 lbs.) of rice. Tarallo noted that an advantage of a cook tank is that it can be programmed to run overnight. "We can put a product in our cook tank and program it to prepare it at night. When we come back in the morning [4 a.m.], it will be nice and cold and cooked," he said.

Glon said he is investigating the possibility of installing a cook tank at his facility. "We want to get into making our own deli meats so, during the next five years, I would like to purchase a cook-chill tank. Also, the equipment is versatile enough to allow us to use the tank to chill bagged products if an emergency arises," he noted.

While blast chillers are not needed at Notre Dame, foodservice at Weill Cornell has found that its two blast chillers work well for preparing lasagna, julienne vegetables and grilled meats for patient meal programs or retail sale. The units fit two mobile pan racks and combi-oven racks can be rolled right in.

Taking a different tack, foodservice staff at New York University Hospital only use blast chillers to bring cooked foods quickly down to safe temperatures. John Hufnal, manager for foodservice equipment, maintenance and repair at NYU Hospital, said blast chillers were chosen to cool foods at his institution because there was not enough room to install a tumble chiller and ice builder.

Although New York University Hospital has been operating a cook-chill system to prepare its patient meals since 1993, it just purchased a 100-gal. steam-jacketed kettle with agitators and a pump station two years ago. Once products have been pumped from this kettle into either hotel pans that are wrapped and sealed or into bags, these are placed on full-size racks and rolled into one of two double-size blast chillers, Hufnal said. Each rack has six to eight shelves and each shelf holds two bags.

"Recently, I installed rockers inside our blast chillers to ensure uniform chilling," Hufnal noted, explaining that rockers shift cooked products so that more of their surface area can be touched by cold air. "We decided to install the rockers because the motion they create enables cold air to flow across a broader surface."

Temperature control and recording is, of course, an extremely important part of cook-chill production. However, most of the operators interviewed by FE&S still rely on dial readers. These paper discs are simple, with pens tracing the temperature history inside each unit. While this monitoring system is adequate, operators would like to have data monitoring systems that download information to their desktop PCs.

The beauty of a cook-chill system is its ability to prepare foods in large quantities and build an inventory of items from which operators can draw as needed. A facility that uses cook-chill preparation equipment needs some supplies that are different in type and quantity than would be used in other commercial kitchens.

For example, the bags or casings into which hot wet foods are pumped have to be able to withstand temperature extremes from 210°F. to -20°F. Claudio Tarallo, manager of foodservice operations for the New York Weill Cornell Medical Center in New York, uses bags that hold 11/2 gals. of product. "We use bags made with a thick gauge of plastic so they will withstand high heat," he said. "We pump our products into the bags at 185°F., which pasteurizes the inside. The plastic also has to be able to go from that temperature to 40°F. in 30 minutes without breakage or distorting. And, it has to be able to be reheated without rupturing."

Because cook-chilled foods are inventoried, it's important that staff draw down their stores on a first-in, first-out basis, making labeling an essential part of the process. Both Tarallo and John Glon, the general manager of the foodservice support facility at Notre Dame University, Notre Dame, Ind., prefer labels made of a waterproof material, which can be attached to bags at the same time they're clipped shut.

"We could use an adhesive label applied directly to the bag," advised Glon, "but I prefer the hanging label because it's easier to grab when we're retherming products. We use a thermal printer to prepare our labels."

Once the bags are filled and labeled, there is a variety of options for handling them during chilling. Because their facilities were set up for cook-chill production, both Glon and Tarallo can bring down foods' temperatures in tumble chillers. At NYU Medical Center, Foodservice Equipment Manager John Hufnal said food-filled bags are rapidly cooled in blast chillers, instead. "We place filled bags into 4-in.-deep steam pans, then place the pans in a rocking cart and roll it into the blast chiller." "We put most of our products on sheet pans because they're going straight from an oven to a chiller," Tarallo said. "Other items, such as lasagna, are chilled in the pans they were baked in, usually 2-in.-deep steam table pans. We also put grilled foods in 2-in. pans." Shallow pans are recommended because they allow cold air to circulate over products more evenly, cooling them rapidly.

After products, whether bagged or panned, have cooled, they must be removed from a chiller and placed in a holding refrigerator or "food bank." At Notre Dame, cooks use bussing bins to hold prepared ingredients, and these bins are used to store chilled bagged products once they're removed from a tumble chiller. "We don't need to use lids," said Glon, "because our bins have lips that allow us to stack them without tops. We just place dollies under a stack of bins or stack 40 on skids so we can use a forklift or pallet walker to put them in a refrigerator or transport them to refrigerated trucks."

Of course, food safety is a prime potential benefit realizable with cook-chill production and regular temperature readings are required to meet HACCP guidelines. At NYU Medical Center, food temperatures are taken manually with probe or immersion thermometers throughout the production process. Hufnal also keeps mechanical thermometers in his walk-ins to verify temperature readings displayed on external chart recorders.

Glon also follows the same procedures. "We use a 'radar-gun' type of thermometer to check surface temperatures of bagged foods as they leave our dock," he commented. "Those temperatures are checked again with probe thermometers when bags arrive at our various campus foodservice facilities." -CK