Food Protection Connection: Safe Food Practices

(reprinted from Dietary Manager, April 2008)

An Aging Population

The population in the United States is aging. In 2000, an estimated 35 million individuals (12.4 percent of the population) were 65 years or older. This number is expected to double by 2030, when 1 in 5 individuals will be over 65. The “oldest old”—those over age 85—is the most rapidly growing sector of older Americans. In 2005, an estimated 5 million people were age 85 or older in the U.S. Thanks to surviving baby boomers, it is expected that 19 million Americans will be age 85 or over by 2050, accounting for one-fourth of all older Americans. These changing demographics will create a challenge for caregivers. Currently, one-third of older Americans (12 million) require long term care. This number is expected to reach 27 million by 2050.

Older adults vary widely in their health status and susceptibility to disease. However, as aging progresses, particularly after age 85, immune function declines. This, along with the effects of chronic diseases and health factors such as malnutrition and immobility, increases one’s risk for both infections and death from infections, including foodborne illness. Those in nursing and long-term care facilities are especially susceptible to foodborne illnesses due to compromised immune systems.

Listeria Monocytogenes

One foodborne disease of particular concern among the elderly population is listeriosis. This is a relatively rare, but severe infection that has only been nationally notifiable since 2000. Listeria monocytogenes, the pathogen that causes listeriosis, is found widely in the environment and may be present in many raw and refrigerated ready-to-eat foods.

Initial symptoms of listeriosis usually appear within 1-2 days of consuming contaminated food and are gastrointestinal in nature, including nausea, vomiting, diarrhea, and sometimes fever. For immuno-competent persons, these may be the only symptoms expressed. However, among individuals with underlying conditions that interfere with Tcell mediated immunity, a more invasive form of listeriosis may develop in two to six weeks with complications such as septicemia and meningoencephalitis. Invasive listeriosis most commonly occurs among persons who are older and/or immunocompromised. Other high risk groups include pregnant women and neonates. Liver disease and use of gastric-acid reducing medications are further risk factors for listeriosis. Elderly persons who contract the disease often require hospitalization. In one study, 96 percent of listeriosis cases among older patients required hospitalization. The disease has a 20 percent death rate, with mortality being highest in the elderly population and particularly among immunocompromised elderly.

Table 1: Participant profile (N=259)

Listeria monocytogenes is a hardy bacterium which resists the deleterious effects of freezing, drying, and heat reasonably well. It has been associated with such foods as raw milk, raw milk cheeses, raw vegetables, and raw meats, poultry, and fish. However, what makes Listeria monocytogenes unique among pathogens is its ability to grow at temperatures as low as 37˚F, permitting multiplication in refrigerated foods. Thus, it is often associated with refrigerated ready-to-eat foods, like deli meats, hot dogs, soft raw milk cheeses, and seafood salads, that support the growth of Listeria to high numbers, are stored for long periods of time and are served without reheating. For example, in 1998-99, 108 people across 24 states were sickened, 14 died, and four miscarried after consuming contaminated hot dogs. In 2000, 30 people across 11 states in the U.S. were sickened by eating contaminated deli turkey. In 2002, over 27 million pounds of ready-to-eat meats were recalled during a Listeria outbreak in the U.S. While there were no large outbreaks associated with Listeria in the U.S. in 2007, salmon dip, smoked salmon, queso fresco, tofu, raw milk and cream, pasta salad, and ready-to-eat turkey and chicken products were just some of the products recalled due to contamination with Listeria monocytogenes.

Dietary Managers Are Key

Dietary managers of facilities that serve older and immunocompromised individuals can play a critical role in minimizing the risk of foodborne illnesses such as listeriosis through the foods they serve, the cleaning, storage and food handling protocols they follow, and the training they provide to their food service staff and residents. As the pathogens that cause foodborne illnesses evolve and/or become more virulent, there is a need to update food safety knowledge and review food handling practices that may need adjustment.

Table 2: Percent of participants whose facilities have cleaning and sanitizing protocols (N=259)

Web Survey

This study was designed to better understand what dietary managers who serve high risk patients know about Listeria monocytogenes, special precautions they take to enhance the safety of the food they serve in their establishments, and their food safety training needs. Researchers from Ohio State and Colorado State Universities adapted a survey which assessed food safety practices and education needs of health professionals to address the current study questions. The developed survey was converted to html format and beta tested by several project team members and dietary managers for content, clarity, and technological issues. Adjustments to the survey were made as needed. The study protocol was approved by the Institutional Review Boards for Human Research at each university.

Members of the national Dietary Managers Association were recruited through the association’s website and electronic newsletter to take the web-based survey. Recruitment began on June 1, 2007 and continued intermittently until February 15, 2008.

Survey Results

As of February 14, 2008, 259 dietary managers had responded to the survey. Information describing the participants is presented in Table 1. Most participants were Certified Dietary Managers, Certified Food Protection Professionals (95 percent) and indicated that they worked for long-term or skilled-care facilities. Respondents were from all regions of the U.S. and represented a wide range of education levels. The majority (60.2 percent) were between the ages of 45 and 59 years.

Table 3: How much heard about Listeria? (N=259)

Table 4: Rating of understanding of Listeria (N=259)

When asked how much they had heard about the bacterium Listeria monocytogenes, 62 percent of the participants said they had heard little or nothing and 26 percent said they had heard “quite a bit” (Table 3). Forty percent rated their understanding of the pathogen as very low to low, 48 percent as moderate, and 12 percent as high to very high (Table 4). This moderate level of understanding of Listeria was evident in that only 63 percent of participants checked elderly adults and only 50 percent checked transplant patients and other immune compromised individuals (two groups they typically serve) as being population groups at high risk of foodborne listeriosis (Table 5). Also, while 95 percent had received specific training on food safety, only 21 percent indicated receiving specific training on Listeria.

Most participants (97 percent) said that they, or others in their establishment, provided food safety information to their kitchen staff. However, only about half of the respondents (53 percent) said they currently provided the residents and patients they served with food safety information.

Survey respondents indicated that their establishments commonly served luncheon meats, hot dogs, and prepared salads—foods associated with outbreaks of listeriosis— to their high risk patients (Table 6). Eight to 12 percent of respondents also indicated that their establishments served meat patés, soft cheeses like queso fresco, and raw or smoked fish, other potential sources of Listeria monocytogenes. J.M. Nelson and colleagues reported that hot dogs and ready-to-eat deli meats are commonly served in long-term care facilities. In their study, 95 percent of establishments reported always heating hot dogs until steaming hot, but few reported heating deli ham (11 percent) and deli turkey (13 percent) to steaming hot before serving.

Participants reported storing opened packages of luncheon and deli meats for a wide range of times, with 12.3 percent storing them for 6 to 7 days, the longest time option given. Most participants (83-96 percent) reported having standard protocols for cleaning and sanitizing meat/cheese slicers, kitchen counters, and refrigerated spaces (Table 2). Fewer, however, said they had standard protocols for cleaning kitchen disposals (39 percent), floor drains (56 percent), and floor sinks (44 percent). These are all locations in the food preparation area where Listeria monocytogenes bacteria are known to colonize. They are also locations that could be sources of cross-contamination to foods prepared in that area.

Table 5: Population groups dietary managers considered to be at high risk of listeriosis (N=259)

Participants indicated strong interest in receiving training on minimizing the risk of listeriosis among high risk patients. They were most interested in receiving this training through a password protected website with internet access to the instructor (70 percent) or a CD-ROM delivered by mail (46 percent), and felt it was somewhat to very important (96 percent) that the training module provide continuing education (CE) credit.

Table 6: Potentially risky foods served in participant’s establishment (N=259)

Conclusions and Recommendations

In this study, dietary managers of facilities that serve elderly and immuno-compromised patients were not well informed about Listeria monocytogenes, nor that their residents are at high risk of foodborne listeriosis. Further, several foods known to be associated with outbreaks of listeriosis, including ready-to-eat deli meats, were commonly served in the study facilities and protocols for cleaning and sanitizing drains and disposals were often lacking.

Participants indicated strong interest in receiving webbased training on minimizing the risk of listeriosis among high risk patients. To be most effective this training should include why elderly and immunocompromised patients are at higher risk of listeriosis, foods of special concern, and factors that affect the growth (and destruction) of Listeria monocytogenes. It should also include how to reduce the risk of listeriosis through careful menu selection and enhanced protocols for cleaning and sanitizing, shorter cold storage times, and cooking or reheating potentially risky foods. The recommendations should be understandable by all, practical, capable of being accomplished, and not adversely affect the quality, nutritional value, or variety of foods served. The information gained in this study will help guide the development of such web-based training for dietary managers.

 

Patricia Kendall, PhD, RD is the corresponding author of this study. She is Professor and Food Safety Extension Specialist, Department of Food Science and Human Nutrition, Colorado State University, Fort Collins, CO. Reach her at pkendall@cahs.colostate.edu; (970) 491-1945.

Additional authors of this study are:

Lydia Medeiros, PhD, RD, Professor and Food Safety Extension Specialist, Department of Nutrition, The Ohio State University, Columbus, OH, medeiros.1@osu.edu

Mary Schroeder, MS, RD, Research Associate, Department of Food Science and Human Nutrition, Colorado State University, Fort Collins, CO

Wei Yuan, MS, Graduate Student, Department of Nutrition, The Ohio State University, Columbus, OH

John Sofos, PhD, Professor, Department of Animal Sciences, Colorado State University, Fort Collins, CO