Food Protection Connection: Food Safety When Batch Cooking

(reprinted from Nutrition & Foodservice Edge, February 2012)

The case that many food sanitarians reference and think about when they inspect large batch cooking operations is the Finley Elementary School E.coli outbreak.

Although the taco meat was not confirmed as the source of the contamination, leftovers showed golf-ball sized chunks with pink under-cooked centers, leading the jury to agree that the undercooked ground taco meat was most likely the culprit that made more than 11 children sick in Finley, WA. You can read more about the Finley Elementary School E. coli outbreak by searching the Internet. No one ever wants to see this happen to children or any population, but lessons can be learned from all unfortunate situations.

Most schools, hospitals, long-term care centers, prisons, and similar facilities that feed large populations use batch cooking (or large volume).  Although there are definite benefits of cooking large volumes of food at one time, it certainly comes with its own risks. Before jumping into batch cooking, consider the following food safety tips:

Delivery and Storage

Do you have the storage space to accommodate your deliveries? Are your refrigerators and freezers large enough to handle food on delivery? If you are going to make large quantities of food, you are going to need to store large quantities of ingredients.  You should carefully consider the size of your dry goods storage, cooler storage, and freezer storage.  Food should always be kept approximately 6 inches off the floor in both dry storage and in walk-in coolers.  I can’t even begin to tell you how many walk-in coolers (and freezers) I’ve seen that I could not even walk into due to overstocking. If you can’t walk into a walk-in cooler, it’s too full and will lead to a variety of food safety violations.  Stuffing walk-ins, or any refrigerator or freezer for that matter, with excessive amounts of food will interfere with air circulation, even cooling, and some foods will struggle to stay at their required temperatures.  Be sure you have enough space!

Preparation, Thawing

Do you have enough refrigerator space and/or preparation sink space to correctly and effectively thaw your frozen foods— especially raw meats? If thawing is necessary, consider whether or not your refrigerators are large enough to handle not only your regular load, but the addition of foods that may need to be thawed over the course of several days.  You should also be careful not to create a situation where raw or uncooked product would cross-contaminate ready-to-eat foods as they thaw.  Finding cross contamination violations while inspecting coolers/refrigerators is unfortunately not uncommon.  This is usually created by overstocking or carelessness when placing items in the units to thaw.  If you cannot or do not want to use refrigerators to thaw foods, there are other alternatives: thaw under cool running water or take food direct from freezer to the cooking process. The FDA Model Food Code 3-501.13, thawing, is very specific on how thawing must occur.  You must thaw food submerged in cool running water (70°F or below) if you are going to use preparation sinks to thaw and not just let the food sit in the sink to thaw.  Make sure the sink is cleaned and sanitized before and after thawing foods, especially raw meats.  Ideally, consider separating sink usage so one prep sink is for ready-to-eat foods and one is for raw foods.

While inspecting a local restaurant, I recall walking over to the two-bay preparation sink that caught my eye because it had a very large cutting board sitting on the two basins with cut lettuce on the top of the cutting board.  I of course lifted off the cutting board to see what was underneath in the sink as any good, nosey sanitarian would.  Wow…in one of the two basins was raw chicken floating in water to thaw (not running water), and in the other connected basin was lettuce soaking—a perfect picture of what not to do!  A sink being used for lettuce preparation like that should not have been used for raw chicken at the same time. The cook needed to consider the potential for cross-contamination (which there most definitely was) and make alternate plans for thawing.

Cooking, Capacity

Do you have large enough kettles, pots, similar containers, and ovens to cook batches of the size you are intending to cook?  Also, do you have enough preparation space in your kitchen to safely prepare food in the volumes you are intending to prepare/cook? If you only have two ovens, how are you going to safely cook 20 turkeys?  If you cook two at a time, what will you do with the prepared turkeys while the next two are cooking?  You need to be able to keep your foods out of the danger zone of 41°F – 135°F. If you are cooking small batches or quantities with the intent to combine them to make a single larger batch, you need to consider how you are going to maintain the cooked product while the remainder of the food is being cooked.  Do you really have enough equipment to accommodate cooking the volume of food you intend to cook? There’s a plethora of specialized equipment for batch cooking:  large volume kettles, ovens, etc.  If you are in the business of cooking large volumes, then you probably already have proper equipment; however, if you only occasionally prepare large volumes, you really need to stop and make sure you can in fact handle the volume while keeping all foods safe.

Cooking, Verifying Temperature

How will you verify and check the final, cooked temperature of the entire batch of food?  When checking the temperature of large batches, you cannot rely on one temperature check. You should check your product in several spots and at various depths. If your product is chunky, as with the taco meat example noted earlier, you should pull a small amount out and give it a visual observation as well.  You may also need to break a few pieces apart.  If both temperature and visual checks concur, you should have a safe, fully-cooked product.  Never rely only on time, color, or texture to tell you when your food is cooked – always take the temperature with a calibrated thermometer to verify.  Large batches must be checked thoroughly and in several locations within the food product to be sure all parts of the food – and not just an isolated pocket – have reached the appropriate cook temperature.

After Cooking: Storage/Cooling
Once cooked, where will you store the large volume of food?  If not served immediately, do you have enough space and equipment capacity to cool these large quantities of food without taxing your refrigeration or freezer units?   I had this happen in a church that was preparing a holiday meal. They just simply forgot to consider where they were going to put all the food when it was done cooking. The excuses we just ran out of space, we don’t have hot boxes, or we are going to re-heat it when we’re ready to serve it are just not acceptable.  These types of excuses cause food-borne illness.  Potentially hazardous food must be held above 135°F or below 41°F or be in the process of cooling.  Food safety can get a bit tricky when you are cooling large batches of food. If you intend to have left-overs or prepare food in advance, you need to consider cooling.

In another example, I recall walking into a restaurant walk-in cooler and having my jaw drop open.  It was a huge cooler with lots of beautiful stainless steel racks—all very clean.  On those racks were well over 50 5-gallon plastic food buckets with lids on.  Confused and concerned, my first question was “what do you have in all these buckets?!”  To my chagrin, the response was the buckets were filled with all of the food they had prepared the day prior for the entire week.  There were no log sheets, no validation of proper cooling, and internal temperatures around 65°F…. a sanitarian’s nightmare!  When I inquired with the operator about why he used the buckets, the response was “they take up less space and I could stack them.”  Needless to say, this resulted in a very large disposal of food and an expensive food safety lesson was learned that day.  If you are going to make large volumes, you must have the space to cool properly.  You will need to divide your large batches into smaller portions to properly and quickly cool the food. That means more space in the coolers and lots of shallow pans. If you are going to cook large batches of food you must also commit to proper cooling. Improper cooling continues to be one of the major causes of foodborne illness, and industry has jumped on board to create equipment to aid if quick cooling.  This may be as simple and inexpensive as cooling wands or large flat metal pans.

In addition, you must be able to actually measure the cooling process, which is not as simple as it may sound.  Test your cooling methods from beginning to end and make sure it works as it should.  You may be surprised with what you find.  Also make sure you follow the allowable cooling times as indicated in the 2009 FDA Model Food Code.

Things to remember when cooling:

• Place food in shallow pans
• Use containers that facilitate heat transfer, such as metal pans.
• Do not cover or loosely cover food that is being cooled.  Cover once the cooling process is completed.  The food must still be protected, but fast cooling far outweighs the possibility of a fleck of dust falling in the product.
• Separate the food into smaller, thinner portions.
• Use rapid cooling equipment if available.
• Use ice baths.  Put food in a container that is then placed in an ice bath.  Stir occasionally.
• Add potable ice at the end of the cooking process as an ingredient.

Don’t let your facility make newspaper headlines for all the wrong reasons.  There is more to a big kettle of soup than meets the eye.  Properly plan large volume meals and consider safety at every step – from receiving the food right through to service and storage afterward.  If batch or volume cooking is part of your everyday work, have a Food Safety Control Plan based on HACCP principles in place, then review and verify the plan regularly.  Document, verify, and serve safety!

by Melissa Vaccaro, MS, CHO
Melissa Vaccaro, MS, CHO is a Food Program Specialist for the PA Department of Agriculture and an Executive Board Member for the Central Atlantic States Association of Food Drug Officials (CASA). Contact her at mvaccaro@state.pa.us.