Recently, while reviewing some documents, I found a Los Angeles Health Department 2005 ACDC Special Report captioned “Please Pass The Bacteria: An Outbreak of Clostridium Perfringens Associated With Catered Thanksgiving Meals”. I liked the title, and thought I would explore the subject of food safety risks associated with catered meals. Thanksgiving is now long past us, but the topic may still be appropriate given the quickly approaching holidays and related celebrations. Not all of us can whip up feasts for many people on our own!
The Maryland Community Health Administration defines catering services as “The preparation or provision and the serving of food or drink by a food service facility for service at the provider’s premises or elsewhere in connection with a specific event or a business or social function or affair”.  In other words, a licensed caterer provides food and/or drink for a specific function at a location generally determined by that specific function.
Image by Flickr.com, courtesy of Aaron Matthews
Caterers must be licensed, and licensing requirements and certifications vary from state to state. Typically, the state Department of Health is responsible for establishing the guidelines for training and certification of all food handlers. Caterers generally must take food-hygiene courses to learn to prepare and serve food items, and to avoid potential hazards that surround the issue of food safety.
Professional caterers are also required to comply with the food safety regulations otherwise applicable to other food service establishments. Officials from the health department will conduct routine inspections to make sure catering businesses have sanitary environments. A caterer must also be up to date with current FDA guidelines for storing and preparing food safely. Catering is specifically included in the definition of a “food establishment” provided by the Food Code 2009: “‘Food establishment’ means an operation that: (a) stores, prepares, packages, serves, vends food directly to the consumer, or otherwise provides food for human consumption such as a restaurant; satellite or catered feeding location; catering operation if the operation provides food directly to a consumer or to a conveyance used to transport people; market; vending location; conveyance used to transport people; institution; or food bank; and…”.
Today, the distinction between grocery and catering businesses is eroding as more and more grocery retailers extend their businesses into offering hot take-away food and delicatessen items. Similarly, some caterers now supply a more traditional grocery line on their premises, usually focusing on the ingredients used in the preparation of their food. Catering businesses, however, must be especially diligent about staff personal hygiene, the hygiene of the equipment and premises as well as staff training. The transient nature of workers in the catering business can put a particularly heavy burden on the ability of the business to train its staff. Unless staff are trained appropriately in food hygiene the risks of food poisoning increase, and many outbreaks of foodborne illness can be attributed to lack of adequate hygiene knowledge and consequential poor practices in catering establishments. 
The epidemiology of general outbreaks of infectious intestinal disease associated with domestic catering for large numbers was described and compared with other foodborne outbreaks in a 1996 British study. From 1 January 1992 to 31 December 1994, 101 foodborne general outbreaks of infectious intestinal disease were identified as being associated with domestic catering in England and Wales (16% of all foodborne outbreaks). Outbreaks occurred most commonly in summer. The commonest vehicles implicated were poultry/eggs in 44 outbreaks, desserts in 13, and meat/meat products in nine. Salad/vegetables, sauces, and fish/shellfish were each implicated in eight outbreaks. Raw shell eggs were implicated in a fifth of outbreaks. Inappropriate storage was the commonest fault, reported in association with 50 outbreaks (ambient temperature for long periods before serving in 29), inadequate heat treatment was reported in 35, cross contamination in 28, an infected food handler in 11, and other faults in 14. Outbreaks associated with catering on domestic premises were independently more likely than outbreaks in other settings to be associated with Salmonella, inappropriate storage of food, and consumption of poultry, eggs, or sauces. 
Data on the number of foodborne illness outbreaks tied to catering can be deceptive. In 1996, approximately 73% of foodborne illness complaints in Massachusetts involved restaurants, while 1% were associated with caterers. When foodborne illness cases are analyzed by establishment type, however, 38% of cases involved catered food. This information illustrates that while outbreaks at catered events are less common, larger numbers of people are affected. Caterers may prepare large amounts of food for large groups, under conditions that are not always ideal. 
Marler Clark has represented clients involved in a number of foodborne illness outbreaks associated with catered food. An unusual one was identified in September, 2004, when health agencies from many U.S. states, as well as international health agencies, began reporting persons ill with Shigella sonnei infections. Tests conducted on many U.S. residents who had cultured positive for the bacteria revealed a matching genetic pattern amongst the samples provided. Epidemiological investigation revealed that a cluster of persons ill with the genetically identical strain of Shigella sonnei had traveled by air from Honolulu, Hawaii during August 22 through 24, 2004. Further investigation established that food from the airline’s catered food service in Honolulu, Hawaii, was the common link between the airlines and the cluster of persons ill with the genetically identical strain of Shigella sonnei. In February, 2005, the Food and Drug Administration (FDA) inspected the caterer’s facility, which provided food and beverage service to various airlines at Honolulu Airport. The FDA identified a litany of violations, including: perishable food holding temperature violations; pest and vermin violations; equipment maintenance and cleanliness violations; and bare-handed contact with ready-to-serve items.
A more representative outbreak occurred in Alexandria, Virginia, in July, 2002. A barbecue was catered at a private home, with approximately 20 coworkers and spouses attending the barbecue. Approximately one week later, the Alexandria Health Department received a report of a confirmed case of campylobacteriosis apparently linked to the barbecue. The environmental investigation by the health department revealed that all foods prepared for the barbecue were prepared the morning of the event, and that several food items were also sold in the catering establishment’s grocery store. The investigation identified several problems with the food handling and preparation procedures for buffalo chicken skewers. The head chef and food worker involved with the chicken preparation for the barbecue provided differing versions of the food preparation procedures. The recipe did not require a cooking time or temperature, and thus there was no way for the person preparing the chicken to know if they had cooked enough to a safe internal temperature. Finally, there was also some indication that the same pan was used to transport both the raw and the cooked chicken. This latter possibility gave rise to the theory that cross-contamination occurred between the previously raw chicken to the cooked chicken.
The Houston Department of Health and Human Services has put together the following questions to ask a potential caterer before an event, to reduce the odds of having the event spoiled by a foodborne illness:
the catering company have a
permit or license?
A. Catering companies are considered food service establishments and must be licensed as a food establishment. You can check to see if they are certified food handlers, who have taken the food safety course offered by many local health departments.
Q: Where is the food cooked?
A. If the food preparation is to take place at the caterer’s establishment, visit the facility. The facility must be clean, provided with enough refrigeration space for large quantities of food, cooking and holding facility for large batches of cooking so that cooking will not need to be done too far in advance. There should be separate areas in the kitchen for handling raw and cooked products as when raw and cooked products mix, cross contamination can cause an illness outbreak. Check to see if the employees in the kitchen follow good hygienic practices by washing hands frequently.
Q: How will they transport the food?
A. The transportation of food, and all raw products is critical. All perishable foods must be held cold (41°F or below) or hot (140°F or above) during transit. The caterers can use refrigerated trucks, insulated coolers, warming units, etc. If they do not, insist on it.
Q: How will the food be kept hot or cold during the party/serving?
A. No cooked food should sit at room temperature for more than two to three hours. Cold foods must be kept at 41°F or below by using coolers, insulated containers, or on a bed of crushed ice. They can serve hot foods from chafing dishes or warming units that maintain the foods at 140°F or above.
Q: How is the caterer planning to replenish foods on buffet tables?
A. The caterer should prepare many dishes of each food to be served. The back up dishes should be kept cold or hot before serving. When the plates are empty, they should be removed and replaced with full trays. It is unsafe to add new food to a serving dish that has been out of refrigeration or hot holding.
Q: What will be done with leftovers?
A. If the food is prepared under safe food handling practices, and held at safe temperatures throughout the party, enjoying the leftovers should be safe. Divide the leftovers into smaller portions for quick chilling or freezing. Use anything you plan to refrigerate within 1-2 days. Make sure that you reheat the leftovers thoroughly before serving. When in doubt, throw it out!
HAPPY PARTYING 
1. “Guidelines for the Prevention of Foodborne and Waterborne Outbreaks for Nonprofit Organizations Who Operate as “Excluded Organizations”, Maryland Community Health Administration, Maryland Department of Health & Mental Hygiene, 2002.
2. Reilly, A., “Defining the responsibilities and tasks of different stakeholders within the framework of a national strategy for food control”, Second FAO/WHO global forum of food safety regulators, Bangkok, Thailand, 12-14 October 2004.
3. Ryan MJ, Wall PG, Gilbert RJ, Griffin M, Rowe B, “Risk factors for outbreaks of infectious intestinal disease linked to domestic catering”, Commun Dis Rep CDR Rev. 1996 Dec 6;6(13):R179-83.
4. Foodborne Illness Investigations and Control Reference Manual, Massachusetts Department of Public Health, 1997.
5. “Catering Tips”, Houston Department of health and Human Services, at
www.houstontx.gov › … › Food Safety Tips