African Journal of Food, Agriculture, Nutrition and Development Rural Outreach Program ISSN: 1684-5358 EISSN: 1684-5374 Vol. 10, Num. 9, 2010, pp. 4000-4015

African Journal of Food Agriculture, Nutrition and Development, Vol. 10, No. 9, September, 2010, pp. 4000-4015

Article

Food safety risk factors in a hospital food service unit serving low microbial diets to immune-compromised patients

SM Hanekom¹, EE Vermeulen², W Oldewage-Theron³

¹ Doctor, TReNDS, a North-West University Centre of Excellence in Nutrition, North-West University, Private Bag x6001, Potchefstroom, 2520, South Africa
² Student, TReNDS, a North-West University Centre of Excellence in Nutrition, North-West University, Private Bag x6001, Potchefstroom, 2520, South Africa
³ Professor, Institute of Sustainable Livelihoods, Vaal University of Technology, Vanderbijlpark, 1900, South Africa

Correspondence Address:S M Hanekom, Doctor, TReNDS, a North-West University Centre of Excellence in Nutrition, North-West University, Private Bag x6001, Potchefstroom, 2520, South Africa, grieta.hanekom@nwu.ac.za

Code Number: nd10092

Abstract

Keywords: HACCP, food safety, immune-compromised, critically ill

Introduction

Food safety is defined as an assurance that food will not cause harm to consumers when it is prepared and/or eaten according to its intended use ^[1]. Food-borne illness caused by micro-organisms is common in food service institutions ^[2]. Although this matter is of some concern for the general public, it is a matter of high concern for immune-suppressed patients (organ transplant, cancer and HIV/AIDS), for whom food-borne infections can be life threatening ^[2],[3]. Other individuals at increased risk of developing more severe outcomes from micro-organisms are the young, elderly and pregnant women ^[4].

The use of low microbial diets (LMDs) for immune-suppressed patients is controversial ^[2],[3],[5]. Low microbial diets is intended to reduce the ingestion of bacterial and fungal contaminants by exclusion of uncooked fruits, vegetables, cold cuts, undercooked eggs and meat, un-sterilized water, un-pasteurized milk produce and soft cheeses ^[1],[6]. Some argue that insufficient research and high cost of LMDs is enough reason not to implement it, while others argue that despite lack of clinical evidence, it is prudent to be cautious and continue to provide immune-suppressed patients with LMDs ^[3],[5]. Wilson ^[6] suggested that to protect the immuno-suppressed patient from pathogens, a regime to eliminate any possible high-risk sources of pathogens should be followed by providing LMDs. Nutritional support is considered by healthcare providers as an integral part of supportive care of immune-suppressed patients. Not only should nutritional support provide the necessary nutrients for body function of the immune-suppressed patient, but it should also entail the prevention of infection ^[7].

Enteric bacteria most commonly associated with food borne infections are Salmonella, Camphylobacter, Shigella and Escherichia coli ^[4] , and associated mortality rate is three times higher than in healthy persons ^[8]. Salmonellosis is estimated to be nearly 20 times more common in AIDS patients than in healthy persons ^[9]. Approximately 75% of reported food borne illness in the United States of America is due to mishandling of food in FSUs ^[10]. A study by Helms et al. ^[8] showed that 55.2% out of 99.4% of patients treated in hospitals for gastro-intestinal infections, had Salmonella infection. The massive Escherichia coli outbreaks in healthy schoolchildren in Japan in 1996 was found to be due to consumption of contaminated radish sprouts served at centralized lunch programs ^[11]. An important aspect in prevention of similar food borne illnesses in immune-compromised patients is the food safety system the FSU uses.

A formal programme for promoting and maintaining food safety is essential in any setting where immune-compromised patients are cared for. Therefore, the Hazard analysis and critical control points (HACCP) program is an ideal, proactive approach to ensure food safety ^[12]. HACCP is defined as a management system ensuring products which are microbiologically, chemically and physically safe ^[13],[14]. This system identifies potential hazards before problems occur. It is applied to the food chain from purchase to consumption. It ensures the safety of food and nutrition products while creating a process for corrective action and continuous improvement rather than relying on spot checks of manufacturing processes and random sampling of finished products to ensure safety ^{[12],[14],[15]}. This program, first developed for the National Aeronautic and Space Administration (NASA) food space program consists of seven main principles namely: 1) Identify hazards and assess their severity and risks; 2) Identify the Critical Control Points (CCP) in food preparation; 3) Establish critical limits for preventive measures associated with each identified CCP; 4) Establish procedures to monitor CCPs; 5) Establish the corrective action to be taken when monitoring shows that a critical control limit has been exceeded; 6) Establish effective record keeping system that document the HACCP system; and 7) Establish procedures to verify that the system is working ^[16]. HACCP principles have since become a widely used reference standard for safe food practices. Even though clear controversy exists on whether to use LMDs or not, safe food handling and general HACCP guidelines can ensure that all sick patients in hospitals get the advantage of receiving safe food. Unless it can be established that LMDs provide no protective effect of reducing risks of infection in immune-compromised patients, two assumptions can be made. Firstly, that LMDs provide some degree of protection against infections attributed to food sources and unsafe food practices, and secondly, that it may be advantageous to continue the use of food service safety protocols that avoid foods potentially containing harmful bacteria to decrease risk of infection for all hospitalized and immune-suppressed patients ^[3].

Because of poor record keeping by the hospital nursing and food service staff, no previous incidences of food borne illnesses in immune-compromised patients linked to food safety and hygiene practices has been documented. Although the first signs of food borne illnesses (diarrhea) was documented in some cases, it was not investigated any further to link it directly to food and hygiene practices, but mostly regarded as the side effects of medicine like antibiotics. The objective for this study was therefore, to investigate the food safety and hygiene status in a hospital FSU serving LMDs to immune-compromised patients, by means of an audit (questionnaire) based on the HACCP principles and bacterial samples.

Subjects and Methods

An investigative study was conducted in the FSU of a 350-bed private hospital in Gauteng, South Africa. The FSU served approximately 1200 meals per day of which an average of 21 meals was served to immune-suppressed patients. The composition and cooking procedures were similar to normal and other diets, but served without fresh garnishes or salads. Each plate was sealed with cling film, delivered to the ward and kept on the serving counter until patients were ready to eat. The food was then heated in a microwave oven and served still sealed. Cutlery was disinfected in boiling water before service.

Methods and HACCP Audit

Microbial data generated through sampling were used to investigate the hygienic performance of the FSU, comparing it to a HACCP audit. Four randomly selected food samples (each weighing 25g), including green beans and potatoes (stewed green beans), chicken gravy, cold meat cuts, and quiche were placed in sterile plastic containers obtained from a registered pathologists on the day of sampling for measuring of TAPC in colony forming units; Coliform, Escherichia coli, Staphylococcus aureus and Salmonella spp. These four food samples from plates destined for immune-suppressed patients were collected 30 minutes after preparation, at the end of the dishing up period. Four surface samples (25cm ² ) for a patient food tray, chef′s hands (gloves), chopping boards used in the salad, cold dessert and sandwich area, and the microwave oven door handle, were swabbed and sealed in a sterile container for measuring of TAPC in colony forming units; Coliform, and Escherichia coli.

All eight samples (food and surface) were stored immediately after collection in a temperature controlled fridge (2°C - 5°C) to minimize bacterial growth ^[17]. These food samples and swabs were delivered to the laboratory within 12 hours of the audit while temperature control was maintained.

An unannounced, independent audit to evaluate current HACCP practices in the FSU, was conducted by the authors. A pre-designed HACCP audit form developed and tested by Societe Generale de Surveillance Group (SGS), South Africa Proprietary (PTY) Ltd, accredited with the South African national accreditation system (SANAS), was utilized. The seven HACCP principles were incorporated in the form for the ten areas (categories) identified for evaluation[Table - 1] of adherence to the set hygiene and food safety principles. Each area, consisting of its own set of questions, was scored as follows: 2 = Excellent, HACCP standards achieved; 1 = Need action plan to improve; 0 = Not up to HACCP standards. Actual scores for each area (and its own set of questions) were calculated as percentage of maximum possible score. A score <80% for any area indicates the need to implement CCP to upgrade current food and hygiene standards and a score >80% means the facility complies to current HACCP standards, as indicated on the audit form. The audit data was analyzed with formulas using Microsoft Excel spreadsheets.

Bacteriological cultures

Ten grams (10g) of each food sample were weighed and diluted in 90 milliliters (mℓ) of peptone water, and then placed in a Stomacher for 2 minutes. Subsequent 10-fold dilutions were made to 10 ^-6. Total Aerobic Plate Count: TAPC is intended to indicate the level of micro-organisms in a product ^[18],[19]. Duplicate dilutions were plated by pour-plate method using South African Bureau of Standards (SABS) International Organization for Standardization (ISO) method 4833:2003. Average counts obtained were expressed as colony-forming units per gram of food (cfu/g) ^[20],[21]. Coliform count and Escherichia coli: Coliforms are defined as gram-negative rods that produce acid and gas from lactose during metabolic fermentation ^[20],[21]. Duplicate dilutions were plated by pour-plate method using violet red agar (VRA) according to SABS ISO method 4832:1991. E.coli was differentiated from other Coliforms using standard microbiological tests. A positive indole test and presence of short Gram-negative rods were taken as positive for presence of E.coli ^[20],[21]. Most E.coli strains are harmless and live in the intestines of healthy humans and animals, but the 0157:47 strain can produce powerful toxins and cause severe illness ^[20],[21]. E.coli count should not be more than 100cfu/25cm ². Staphylococcus aureus : Dilutions were plated onto Baird-Parker agar base containing appropriate supplements, using the spread-plate method, according to ISO method 6888:1993E. Five typical colonies were picked off and the coagulase test was conducted using Staphylase Kit Dir 595. Coagulase-positive colonies were recorded as S.aureus ^[20],[21]. Salmonella: Ten grams (10g) of each food sample taken were placed into 225 ml of buffered peptone water and incubated at 37°C for 24 hours according to SABS ISO method 6579:2002. Presence of Salmonella was determined by means of laboratory tests designed to identify this form of bacteria ^[20],[21].

Permission to conduct the audit was obtained from the Food Service manager of the FSU and the Safety, Health, Environment and Quality (SHEQ) coordinator of this medical hospital.

Results

Results gathered from the audit are represented in [Table - 1]. The following 10 areas with actual and maximum possible point scores and % given in brackets, were evaluated: 1) receiving [10/22: 45.5%]; 2) dry and refrigerated storage [16/50: 32%]; 3) sub-zero storage [3/18: 16.3%]; 4) preparation and production [30/62: 48.4%]; 5) service and distribution [25/36: 69.4%]; 6) customer area [15/22: 68%]; 7) premises and equipment hygiene [19/42: 45.2%]; 8) staff standards [11/18: 61%]; 9) sanitary facilities [2/10:20%]; and 10) quality procedures and records 1/18:5.6%]. None of the ten areas audited met acceptable food safety standards (average for all 10 areas = 41.1%). Category 5 had the highest (69.4%) and category 10 the lowest (5.6%) scores. The score for category 7 was low at 45.2%. Staff premises (sanitary facilities) category 9, scored even lower at 20%.

Microbial loads on the patient food tray and chopping board both had higher than permitted counts of 870 cfu/25cm ² and 350 cfu/25cm ² , respectively for E.coli (normal < 100 cfu/25cm ² ), and >1000 cfu/25cm ² for TAPC and Total Coliforms (TCs), respectively (normal < 100 cfu/25cm ² ) [Table - 2].

Surprisingly, the chef′s hand and the microwave oven door handle in the ward kitchen showed no microbiological activity at all. TAPC [Table - 3] for green beans and potato, cold meat cuts and quiche were within normal range. Chicken gravy had a high TAPC of 12700 cfu/g, E.coli of 280 cfu/g and TCs of 2760 cfu/g. The cold meat cuts had an E.coli count of 30 cfu/g where none should be present while the TCs were barely below normal range. No Staphylococcus aureus or Salmonella spp were found on any food item.

Discussion

Contamination of food due to poor hygiene practices, temperature control, receiving of contaminated food from suppliers, incorrect storing regimens and cross contamination may be a serious problem when the HACCP audit report and laboratory analysis for this study is investigated. Contaminated equipment was found, which supported cause for concern that surface hygiene practices in the FSU was not properly executed. The low dishwasher temperature (<38 ^o C) is cause for concern, because only with very hot water (>82°C) can thermal disinfection be obtained ^[14]. No disinfection liquids or bleach to disinfect crockery and cutlery without hot water was available, according to the audit report. High microbial loads were found in some of the surface swabs [Table - 2]. Both the patient food tray and chopping board contained high counts of Coliforms, E.coli and TAPC.

Raspor and Jevšnik ^[1] stated that "safe food is a consumer′s basic right". The nature of food and extent to which it is handled make the opportunity for contamination commonplace. A major goal, according to Dezenhall et al. ^[19] of any hospital FSU should be to provide food that is microbiologically safe because hospitalized patients with impaired immunity are more susceptible to infection and consequent morbidity and mortality ^[18],[19].

According to the Food and Drug Administration (FDA) ^[22] and Barrie ^[14] several important factors could cause food borne illness in a FSU. These factors are 1) food received from unsafe and contaminated sources, 2) inadequate cooking and re-heating temperatures, 3) improper holding temperatures, 4) contaminated equipment, 5) preparing food too long in advance, 6) cross contamination between raw and cooked food, and 7) poor personal hygiene ^{[14],[22],[23]}. On visual inspection it was found that the FSU received food from suppliers that were not HACCP approved which meant that food could have been bacterially compromised before reaching the FSU. It is the responsibility of all parties included in the food chain to ensure food traceability and food safety by internal control in all production phases according to HACCP principles ^[1]. The fact that no food cooking or holding temperatures were recorded in this FSU may have led to temperature abuse and eventual spoilage, specifically with regard to chicken gravy as confirmed by the microbial results ^[17]. The importance of hand washing and good personal hygiene practices are highly emphasized and may prevent contamination and food borne illnesses, especially in immune-compromised patients.

Food handlers must be educated by an infection control team in the significance of safe handling of food by addressing good manufacturing practices (GMP) and hygienic food preparation topics such as hand washing procedures, sterilization of equipment and work surfaces, and elimination of cross-contamination, to ensure consumer protection from food borne illness ^{[1],[14],[24]}. However, FSU management should also ensure that the necessary cleaning materials are available for use by food handlers. The audited FSU also complied poorly to the South African Occupational Health and Safety Act ^[25]. Although a copy of the Act was filed, no monthly audits or formal induction training on health and safety issues had been done, a first-aid box was not available, and safety user instructions were not displayed at equipment. Assured safe catering is a practical method based on risk assessment (CCP) and involves investigating each operation (task) step by step.

The non-identification of weak points in the general management of food production and correction thereof in this FSU, are cause for concern ^[1],[26]. A systemic approach, such as the HACCP system, to identify, evaluate and control food safety hazards must be carried out to achieve food safety and to prevent food borne illnesses ^{[26],[26],[27]}. Although oral reports of specific training relevant to work was given, no record to this account could be found. If training and re-training takes place on a regular basis, no contaminated food items should be found on the premises, provided all necessary precautions are taken and cleaning and sanitizing materials are available in the FSU. Legnani et al. ^[28] performed 236 inspections for ±10 years on 27 catering establishments in the province of Ferrara, Italy, after the HACCP system was introduced and educational programs for food staff was undertaken ^[28]. Their results revealed an improvement in the microbiological quality of food and equipment. The positive impact of training on safe food handling practices can improve from 11.7% to 75% as soon as two months after training ^[10].

A study by Shojaei et al. ^[29] showed that poor personal hygiene by food handlers frequently contributed to outbreaks of food borne illnesses caused by enteric bacteria ^[29]. In the audited FSU the same cutting boards were used for raw and cooked food, without sufficient sterilizing in between the tasks. The presence of E.coli on surfaces may be ascribed to poor hygiene practices as a result of the absence of cleaning materials in both the staff sanitary facilities and the FSU, as identified by the audit (20% score achieved). Only a small amount of these enteric bacteria are required to cause illness, especially in immuno-compromises patients ^[17]. The fact that no microbial activity was found on the chef′s gloves may be ascribed to the changing of gloves just before the swab was taken. Enteric diseases are among the most devastating problems in persons with AIDS, where 50-90% suffers from chronic diarrhea illnesses which can be fatal. The rate of diarrhea in HIV-infected patients in developing countries are higher than in developed countries, reflecting more frequent exposure to enteric pathogens. The fact is that outbreaks of food borne infection in hospitals are, however, preventable ^[30].

Even though patients did receive LMDs in this survey, some of the food items still had high microbial counts which increased the risk of food borne illnesses. From the audit it became clear that large numbers of food items where stored directly on floors in opened tins and containers without covering while no "use by" dates were evident and most of storage shelves were rusted. These practices could have contaminated food and contributed to high microbial counts found on some of the food items. The cold meat cuts had high counts of several of the tested microbes, which could be explained by poor personal and equipment hygiene practices, and removed from the fridge long before use, leaving it at room temperature. Poultry products support the growth of disease-causing and spoilage micro organisms. The intestinal track and skin of poultry may contain a variety of food borne disease bacteria, including Salmonelle spp., E.Coli and Campylobacter jejuni ^[17]. Chicken breasts were left at room temperature (±25°C) rather than the cold storage facility, for defrosting. Rapid bacterial growth takes place at temperatures >21°C, while most disease-causing bacteria can grow within a range of 5°C to 57°C ^[17]. The major causes for concern in these instances are the poor hygiene and food safety protocols present in the FSU. It is the authors′ opinion that it may well be wise to eliminate products, such as chicken, which may be hazardous to patients when not handled according to strict hygiene and safety measures and HACCP principles, from the menu.

Conclusion

The results of the study confirmed that, besides mainly focusing on the selection of food items allowed and cooking methods used in LMD, the type of food service and food and safety protocols followed, could play an important role in providing food that is safe for immune-compromised patient use. The implementation of HACCP system, while not without its own challenges, is essential to produce hygienically prepared meals safe for human consumption, especially when the patient is immune-compromised. It is important to take into account any co-existing diseases such as HIV/AIDS when food hygiene becomes a problem, because of increased morbidity rate ^[8].

Results of this study should also serve as a warning for all other hospital FSUs to ensure safe food for all patients. Although this was an investigative study and an intervention process was not part of this study, the data can still be of substantial value for future use in planning and implementation of food safety measures in a hospital FSU. A follow up study is recommended where a detailed HACCP action plan, after a first phase of inspection has taken place, is planned and implemented. Intensive personnel training and motivation will form an essential part of the HACCP implementation. After HACCP implementation three follow-up audits should be done after a selected time lapse by independent auditors to prevent bias. The results of these audits could be compared to investigate improvement in the quality of food as well as safety standards. Standard audit forms and patient questionnaires can then be used when food borne illnesses are documented during the hospitalization period of immune-compromised patients. Oral food intake, patient satisfaction and nutritional status of patients could also form part of a follow-up study. Bacterial analysis of food and surface areas can be used to correlate improvements and identify possible topics for retraining.

The results of the audits could be compared to investigate the quality of food as well as safety standards. Standard audit forms and patient questionnaires can then be utilised when food borne illnesses are documented during the hospitalization period of immune-compromised patients. Oral food intake, patient satisfaction and nutritional status of patients could also form part of a follow-up study. Bacterial analysis of food and surface areas can be used to correlate improvements and identify topics training of staff in the FSU.

References

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