632

Journal of Protection Vol. 40, No. 9, Pages 632-638 (September, 1977) Copyright 'c'; 1977, International Association of Milk, Food, and Environmental Sanitarians

HACCP Models for Quality Control of Entree Production in Systems

BARBARA J. BOBENGl and BEATRICE D. DAVID

Department ofFood Science University of Wisconsin-Madison

Madison, Wisconsin 53706 Downloaded from http://meridian.allenpress.com/jfp/article-pdf/40/9/632/1650019/0362-028x-40_9_632.pdf by guest on 01 October 2021

ABSTRACT QUALITY AND QUALITY CONTROL IN THE Quality control is a major management function in foodservice systems. Quality is defined as a composite of microbiological, FOODSERVICE INDUSTRY nutritional, and sensory attributes. The Hazard Analysis Critical In the foodservice literature, quality of food generally Control Point (HACCP) concept is a preventive approach to quality referred to sensory attributes such as and control, emphasizing microbiological control and identifying process stages where loss of control could present a risk. Applying appearance. Temperature was also considered a sensory this concept, which has been implemented in the processing attribute with unique importance as a quality factor for industry, HACCP models were developed for quality control of entree foodservice systems. production in conventional, cook/chill, and cook/freeze foodservice Traditionaliy, quality controi in foodservice systems systems in three phases: identification of control points using flow has been interpreted as a threefold process: specify diagrams, identification of critical control points, and establishment of monitors for control. Time-temperature was a critical controi point quality , utilize standardized recipes, and throughout entree production in each of the models; parameters were taste the food critically (20). Emphasis was usually on established for time-temperature and continuous surveillance of tasting the fmished product. In fact, Miller (29) stated time-temperature was the monitor for control. Equipment and that the only measure of quality was to taste food personnel are critical control points which should be continuously. This alleged measurement lacks reliability monitored using standards established by the foodservice system. Implementation of the HACCP system is recommended for foodservice and validity as a tool for quality controL operations. However. standards and monitors for control of critical control points must be established for each operation and based on their QUALITY AND QUALITY CONTROL IN THE own system objectives, resources, and constraints. INDUSTRY Quality is usually defined in the food processing literature as a composite of microbiological, nutritional, Quality of meals is a primary objective of food service and sensory attributes. Kauffman (24) considered food systems; therefore, control of quality is a major quality as highly acceptable organoleptic characteristics, management function. Generally, quality assessment in nutritional value, and safety. Hawthorn (21) defined foodservice systems involves inspection at the point of quality as a composite of positive and negative factors. service, a retrospective action which provides little Positive factors included color, flavor, texture, and nutri­ information for quality control. tional value; whereas, quality, was also freedom from Quality is a multi-dimensional characteristic of food, negative factors such as harmful and defined for this paper as a composite of microbiological, undesirable substances. nutritional, and sensory attributes. The literature was Quality of food is related to consumer acceptability. reviewed to determine perceptions of quality and Although quality is frequently confused with excellence, emphases of quality control programs in foodservice it is only a specified degree of excellence required in the systems and in the food processing industry. The Hazard marketplace as determined by the consumer's willing­ Analysis Critical Control Point (HACCP) concept, which ness to pay (25). has been successfully implemented in the food processing Quality control and quality assurance are terms industry, was investigated for its applicability to which have been used interchangeably in the literature. foodservice systems. Recently there has been an apparent differentiation in terminology. Quality assurance is an overall program directed toward compliance with food laws and 'Present address: Depanment of Institution Management. Iowa State regulations; whereas, quality control is one aspect of the University. Ames. !A 50011. total quality assurance program (2,35). QUALITY CONTROL IN FOODSERVICE 633

The purpose of quality control in food processing ing and determining consequences of an event occurring systems is to insure quality at levels and tolerances during a given process; each processor should determine acceptable to the consumer and at minimum cost to the what is critical to that operation, even though it may not processor (25). Quality control can. be considered in be covered by regulations. three stages: raw material control, process control, and In contrast to canned food processing, a heat treatment fmished product inspection (21). Emphasis may be that eliminates all viable microorganisms is rarely appropriately placed on any one stage, since the quality applied in frozen food processing. The approach to the control program should be designed to meet the HACCP system for frozen food processing has implica­ specialized requirements of the processing operation (30). tions for the food service industry. Raw material control is actually a misnomer. The term Many critical control points may be identified in "control" may imply that all food properties are under the processor's control; this is true only to the degree that frozen food processing, contributing to a "net effect phenomenon". Each critical control point independently control extends to the farm level. Processors can and do

contributes to the net microbiological condition of the Downloaded from http://meridian.allenpress.com/jfp/article-pdf/40/9/632/1650019/0362-028x-40_9_632.pdf by guest on 01 October 2021 specify microbiological standards for raw materials, finished product. If the microbiological limit for any one controlled by testing these raw materials before critical control point is exceeded, control at preceding acceptance. "Control" may also imply improvement in and subsequent critical control points may be negated. the quality of some raw materials during processing. Exceeding the limit at a critical control point may also However, the objective is to conserve the quality of raw have an additive effect on the microbiological condition materials during processing. Finished product inspection has a confirmatory function in a quality control program, of the finished product (10). identifying the effectiveness of raw material and process Corlett (11) presented generalized models for basic control (21). processing sequences for frozen . Although food Quality control is a management function integrated items and processing complexities differed, critical into all subsystems of the food processing organization. control points were similar: microbiology, sanitation, Quality control is a dynamic concept which should time-temperature, and employee cleanliness. Frequency adapt to changes in materials, machines, and the of monitoring controls varied with the situation; controls market. were monitored as often as necessary to assure that critical control point limits were satisfied. Development of microbiological limits was discussed, emphasizing the HACCP CONCEPT need to use limits to measure specific conditions; limits The HACCP (Hazard Analysis Critical Control Point) may be too restrictive or too relaxed if incorrectly system is a preventative program for quality control applied to different foods or processing circumstances. designed to inform management of potential dangers so Microbiological testing of finished products, to provide a that corrective action can be taken. Kauffman (24) basis for ultimate acceptance or rejection of the product, reported that many industry leaders, trade associations, is completed while the product is still under the and regulatory agencies consider that the HACCP system processor's control. is the best quality control program yet devised to assure Generalized models for HACCP systems in frozen food safe foods in the marketplace. processing operations were also presented by Peterson The objective in developing the HACCP approach was and Gunnerson ~2). Critical control points were to apply a zero-defects concept to production of food, established at all places in the processing sequence where considering ingredients, processing steps, and potential microbial contamination or proliferation could occur. for consumer abuse ~). The analysis of hazards of Critical control points included raw product control and ingredients was based on a classification of food products storage, facility sanitation and maintenance, equipment according to risk of salmonellosis (30). Adequate process sanitation, employee personal hygiene, microbiological control of both biological and physical hazards required: population, and time-temperature. The interdependence (a) delineation of all physical systems, identifying of critical control points was discussed; loss of control at hazards to food safety; (b) elimination of hazards that are one critical control point may result in an additive totally correctable; and (c) establishment of a control microbiological effect or loss of control at subsequent system for any hazardous condition which must remain critical control points. part of the process. The potential for consumer abuse required precautions to prevent failure of the product Peterson and Gunnerson ~2) emphasized the feedback through transportation, distribution, and consumer use characteristics of the HACCP system. Microbiological ~). testing of the equipment and personnel sanitation, The HACCP approach requires examination by in-process food samples, and fmished products yielded qualified personnel of all processing operations to results too late to be effective for that product. The value identify hazards, establish controls, select test pro­ of microbiological testing was in identifying problem cedures, and establish sampling schedules (13). Ito (23) areas and problem situations in processing, leading to suggested identifying critical control points by question- increased preventative activities. 634 BOB ENG AND DAVID

GENERALIZED HACCP MODELS FOR TABLE 2. Critical control points during entree production in three FOODSERVICE SYSTEMS foodservice systems HACCP models were developed for entree production Critical control points Time- in conventional, cook/chill, and cook/freeze foodservice control and Equipment Personnel temperature storage sanitation sanitation relationship systems in three phases: identification of control points Control points using flow diagrams, identification of critical control Procurement1 '2 ' 3 X Preparation1 ' 2 '3 X X X points, and establishment of monitors for control (6). Heating1 '2 '3 X Hot holdingl X Control Points Chilling and chilled storage' X X Freezing and frozen storage3 X A control point has been defined as a point in a process Thawing3 X X 3 where a potential food hazard may exist (12). Control Portioning and assembly'' X X X Portioning, assembly, and points are process stages of entree production for the 1 X X X

distribution Downloaded from http://meridian.allenpress.com/jfp/article-pdf/40/9/632/1650019/0362-028x-40_9_632.pdf by guest on 01 October 2021 generalized HACCP models. Cold holding and Table 1 identifies the control points in the flow of distribution' '3 X X Heating''3 X entree production for conventional, cook/chill, and Service1 '2 ' 3 X X X cook/freeze foodservice systems. As depicted, there are 1Conventional several identical control points in two or all three of the 2Cook/Chill systems. 3Cook/Freeze

TABLE 1. Control points during entree production in three food­ senJice systems Specific standards for control at the critical control Foodservice systems points will have to be determined by each foodservice Conventional Cook/Chill Cook/Freeze system. Some factors contributing to microbiological Procurement Procurement Procurement control at critical control points are discussed. Preparation* Preparation* Preparation* Ingredient control and storage Heating* Heating* Heating* Ingredient specifications are statements of desired * * quality. In addition to providing sensory and quantitative Hot holding* Chilling and chilled Freezing and frozen descriptions of the food item, specifications should storage storage provide for microbiological control of ingredients by Thawing* identifying the wholesomeness of food at the source, type of packaging, and time-temperature during transit (27). Portioning and assembly Portioning *and assembly Temperature control is necessary to maintain both the Portioning, assembly microbiological and sensory quality of refrigerated and and distribution frozen food. Ingredients should be procured from Cold holding and Cold holding and distribution distribution sources that comply with all laws relating to food and food labeling (14). Heating* Heating* Inspection of food upon receipt is necessary to Service Service* Service* ascertain that specifications have been met. In addition to visually checking, counting, and weighing food, temperatures of refrigerated and frozen food should be These systems may differ in implementation among foodservice operations; however, as described here, recorded. Items that do not meet specifications should be rejected. entrees are prepared, cooked, and stored in bulk either Time spent in receiving and inspecting food should be hot, chilled, or frozen. Entrees are then portioned, and minimized by specifying delivery and scheduling meals are assembled and distributed. In cook/chill and adequate personnel for this function. Food, especially cook/freeze systems, entrees are heated before service. refrigerated and frozen items, should be promptly stored under suitable conditions. An objective of is to prevent or control Critical Control Points loss or waste from deterioration or infestation (38). Critical control points are those points in a process Control of ingredients in storage should include removal that eliminate or reduce a microbiological hazard (12). of items suspected of quality deterioration, especially Four critical control points were identified for HACCP from microbial spoilage. models for foodservice systems: ingredient control and The critical control point, ingredient control and storage, equipment sanitation, personnel sanitation, and storage, includes time-temperature considerations time-temperature. For each control point identified in during storage. Three types of ingredient storage based Table 1, one or more of the four critical control points on temperature are provided in foodservice systems: dry, were pertinent; see Table 2. refrigerated, and frozen. Optimal times and tempera- QUALITY CONTROL IN FOODSERVICE 635 tures for storage of ingredients should be established to be the responsibility of both management and food­ retard deterioration. Some generalizations can be made service personnel. Management should be observant for regarding temperature of storage; time or shelf life of signs of illness in personnel and should encourage storage should be determined for individual ingredients. personnel to report all illnesses, especially those of Dry storage is for food requiring protection against the skin and gastrointestinal and respiratory tracts. invasion of rodents, infestation with insects, and Absenteeism for verifiable illnesses should not be bacterial contamination, but not requiring refrigeration. penalized; personnel should not return to work until the Storage areas should be at 10-21 C, well-ventilated, and infectious stage has passed (36,37). dry with a relative humidity of about 50-60% (27). Food Persons who are healthy may also transfer pathogens should not be stored under exposed sewer or non potable to food by air or physical contact during food handling lines or in contact with water or undrained ice (14). activities. Cleanliness, clothing, and practices of per­ The temperature of potentially hazardous food sonnel are specified by the FDA (14); however, requiring refrigeration should be 7 C or below; food interpretation of "good hygienic practices" is left to should be stored in facilities equipped with a individual discretion. Personal hygiene and sanitary Downloaded from http://meridian.allenpress.com/jfp/article-pdf/40/9/632/1650019/0362-028x-40_9_632.pdf by guest on 01 October 2021 thermometer accurate to ± 1.6 C (14). Longree (27) work practices were discussed by several authors recommended optimal refrigerated storage temperatures (1,27,38). The importance for foodservice personnel of by food category: dairy products and eggs, 2-4 C; meat educational programs which include sanitary food and poultry, -1 to 2 C; fish, -1 to 0 C; and fruits and handling practices was emphasized in the literature. vegetables, 2-4 C. In addition, cross-contamination of Time-temperature raw and cooked food during refrigerated storage should Factors related to abuse of the time-temperature be avoided. Fresh meat and produce are frequently relationship in food have frequently contributed to sources of pathogenic microorganisms ()1). foodborne disease outbreaks (8). Factors included: Frozen food should be stored at -18 C or below (}4). inadequate refrigeration, preparing foods far in advance Food should be packaged in materials which are of planned service with improper storage during the impermeable to moisture and oxygen. interval before serving, inadequate heat processing, and Equipment sanitation holding foods in warming devices at temperatures that The potential for bacterial contamination of entrees favor bacterial growth. from equipment and utensils exists at several control or The critical control point "time-temperature" refers process stages; equipment sanitation is a critical control to the relationship of time and temperature at control point. points of entree production. Time-temperature is a Bryan (8) reported that two factors contributing to critical control point at all of the control points in Table foodborne disease outbreaks were inadequate cleaning of 2 except procurement. The time-temperature parameter equipment and cross-contamination; specific sources of is included in the critical control point, ingredient contamination were not described. Stauffer ()7) indicat­ control and storage. Time-temperature parameters for ed that in many outbreaks common links between foodservice system control points are based on the zone contaminated fresh foods and cooked food were sinks, of growth for microorganisms in food. The FDA has knives, cutting boards, and hands. promulgated the regulation that the temperature of The Food and Drug Administration (FDA) has potentially hazardous food must be 7 C or below or 60 C proposed uniform requirements for food service sanita­ or above at all times, except during preparation and tion; one section contains specific requirements for heating (14). cleaning, sanitization, and storage of equipment and Time-temperature standards for control points in utensils (14). Procedures should be established by each conventional, cook/chill, and cook/freeze foodservice foodservice system for cleaning and sanitizing equip­ systems are in Tables 3, 4, and 5. The basis for these ment, including methods, materials, and frequency of standards was to minimize the time that the temperature cleaning. Practical information to assist in developing of entrees was in the zone of growth for , procedures is in books and trade journals (19,26,28,33). 7-60 C. Some factors considered in determining time· Personnel sanitation temperature standards for control points follow. At all control points or process stages in entree 1. During preparation in all three systems, the production where food is handled, personnel sanitation is temperature of entrees may be within the range of 7-60 C a critical control point. Personnel may directly or (14). Since this temperature zone will permit bacterial indirectly contribute to microbiological contamination. growth, time should be minimized. A centralized Personnel who are infected with a disease should not materials handling unit is one method for reducing the be working in the foodservice (14). Bryan (8) reported time that food is at ambient temperature by decreasing that infected persons practicing poor personal hygiene the time that cooks spend searching for, collecting, and were major contributors to foodborne disease out­ transporting ingredients. breaks; this factor contributed to 151 of 725 outbreaks 2. Most entrees requiring heating should be cooked to reported from 1961-1972. Health consciousness should heat all parts of the food to at least 60 C. Poultry, poultry 636 BOBENG AND DAVID

TABLE 3. Time-temperature critical control points at control points the conventional system should be at least 60 C; the during entree production in a conventional foodservice system storage facility for hot holding should be equipped with a Critical control point thermometer accurate to ± 1.6 C (14). This temperature Control point Time Temperature should prevent bacterial growth but may not be sufficient Preparation Minimal 7-60C to destroy bacteria. For entrees at 60 C or above, time of Heating _2 ;;.60 C3 hot holding was not a factor for microbiological control. Hot holding _2 ;;.60C Portioning, assembly, and Temperature of entrees during hot holding should be distribution Minimal ;;.60 c increased depending on the specific entree and Service Minimal ;;.60C foodservice system. Since the preferred eating tempera­ 'Internal temperature of entree at completion of control point activity. ture for hot entrees is 60-63 C, the cooling rate of the 2Time will vary with entree, equipment, and/or system. 3Minimum temperature; will vary with entree. entree and the time lapse between portioning and assembly and service should be considered (4). In TABLE 4. Time-temperature critical control points at control points addition, since hot holding equipment is designed to Downloaded from http://meridian.allenpress.com/jfp/article-pdf/40/9/632/1650019/0362-028x-40_9_632.pdf by guest on 01 October 2021 during entree production in a cook/freeze foodservice system maintain rather than increase temperature of food, Critical control point entree temperature should be higher than 60 C at the Control point Time Temperature onset of hot holding. Blaker and Ramsey (5) determined Preparation Minimal 7-60C that steam tables were able to maintain food at 60 C for Heating _2 ;;.60 c at least 1 h if food was 71 C or above when it was placed Chilling .;; 4 h4 ;;.7c in the steam table. Chilled storage .;; 20 h4 .;; 7C Portioning and assembly Minimal

considered in determining heating times. Downloaded from http://meridian.allenpress.com/jfp/article-pdf/40/9/632/1650019/0362-028x-40_9_632.pdf by guest on 01 October 2021 Longree an discussed on-premise freezing of cooked 10. During service in all three food service systems, the food and cautioned that bacteriological hazards could be temperature of hot entrees should be maintained at 60 C formidable if the total production process was not or above. Service should be supervised to minimize bacteriologically controlled. Recommendations included delays. freezing food in small, shallow batches so that food is solidly frozen within one-half hour of exposure to Monitors for Control freezing temperatures; the temperature of freezing equipment was not given. The effectiveness of control measures at critical Storage temperature of -18 C or below is specified for control points should be determined by establishing frozen food (14). Damage during frozen storage was monitors for control. HACCP control measures for attributed to recrystallization caused by fluctuating frozen food processing were evaluated for applicability to temperatures. Generally, below -15 C, the rate of foodservice systems. deterioration decreases as temperature is lowered an. Microbiological testing of ingredients, critical control Time of storage at -18 C or below has not been a points, and finished products is a key criterion for consideration for microbiological control because bac­ HACCP control in frozen food processing; results of terial growth is retarded at subfreezing temperatures. microbiological analyses are compared to established However, Glew (18) recommended a maximum shelf life microbiological limits (11). However, Peterson and of eight weeks. Gunnerson ~2) emphasized that results of microbio­ 6. Thawing frozen entrees in the cook/freeze system logical analyses are obtained too late to be useful for the should be accomplished in refrigerated units. The lot being tested. The importance of anticipating and temperature of potentially hazardous foods should not preventing microbiological problems in the HACCP exceed 7 C during refrigerated thawing (14). Bacterial system was stressed. Peterson and Gunnerson stated that growth was retarded at temperatures below -18 C; much of in-process control consists of maintaining however, growth is resumed when food is thawed. time-temperature standards and may involve continuous Bacteria can multiply when ice crystals are converted to surveillance. free water; therefore, food temperature should be Establishing time-temperature standards is a practical maintained at 7 C or below to control growth of method for monitoring entree production in foodservice microorganisms. Thawed entrees should be used systems; standards for conventional, cook/chill, and promptly' preferably refrigerated for only a day an. cook/freeze systems are in Tables 3, 4, and 5 (6). If 7. During portioning, assembly, and distribution in continuous surveillance of time-temperature is imple­ the conventional system, entree temperature should be at mented, immediate feedback is available for corrective least 60 C or above. Temperatures should be increased action. With experience in monitoring time-temperature, depending on the specific entree and foodservice system; critical control points, where the frequency of monitoring factors to consider in determining the optimal tempera­ may be decreased without decreasing control, can be ture were discussed for hot holding. identified. In the cook/chill and cook/freeze systems, the Monitors for control of equipment sanitation and temperature of "cold" hot entrees should be maintained personnel sanitation are necessary to measure adherence at 7 Cor below during portioning and assembly. to established policies and procedures for sanitation (6). 8. Cold holding and distribution in the cook/chill and cook/freeze systems is that period following portioning APPLICATION OF HACCP FOR QUALITY CONTROL IN and assembly. Meal trays are either stored in refrigerated FOODSERVICE SYSTEMS trucks for distribution to service units or placed on racks The goal of in-process control of entree production is which are distributed to service units and stored in to conserve the inherent quality of the ingredients. The refrigerators. Temperature of "cold" hot entrees should HACCP system is a preventative approach to quality be maintained at 7 C or below; holding time will vary control, emphasizing microbiological control and 638 BOB ENG AND DAVID

identifying process stages where loss of control could 11. Corlett, D. A., Jr. 1974. Frozen food processing technology. present a food safety risk. Conservation of nutritional Presented at the HACCP Inspector Training Courses, FDA, and sensory quality was incorporated in the HACCP September 18 and October 9, 37 pp. 12. Corlett, D. A., Jr. 1975. Personal communications to B. D. David models developed for the three foodservice systems. It January8. was postulated that adherence to the minimal tempera­ 13. Curtis, J. E., and G. E. Huskey. 1974. HACCP analysis in quality ture standards for heat processes would not only control assurance. Food Product Dev. 8(3):24-25. microbiological quality but would also conserve the 14. DREW. 1974. Food service sanitation. Proposed uniform nutritional and sensory quality of the entree (6). requirements. Federal Register 39(191):35438-35449. 15. Dorney, D. C., and G. Glew. 1974. Food freezing. Hospitals, Implementation of the HACCP system was recom­ J.A.H.A. 48(13):128, 130-131, 134. mended for foodservice systems. However, standards and 16. Dorney, D. C., J. Millross, and G. Glew.1974. Packaging, storage, monitors for control of critical control points must be and transport. Hospitals, J.A.H.A. 48(14):81-83. 17. Fennema, 0. R., W. D. Powrie, and E. H. Marth. 1973. Low­

established for the foodservice operation and should be Downloaded from http://meridian.allenpress.com/jfp/article-pdf/40/9/632/1650019/0362-028x-40_9_632.pdf by guest on 01 October 2021 based on system resources and constraints (6). Silverman temperature preservation of foods and living matter. Marcel Dekker, Inc., New York. 598 pp. (.34) indicated that the effectiveness of attempts at quality 18. Glew, G., ed. 1973. Cook/freeze catering: An introduction to control in food services are often negated by failure to its technology. Faber and Faber, London. 168 pp. establish written procedures and effective training and 19. Guthrie, R. K. 1972. Food sanitation. The Avi Publishing Co., supervision. Inc., Westport, Connecticut. 247 pp. Using the HACCP approach, inspection of critical 20. Hart, K. 1957. Tools for cost and quality control. J. Amer. Dietet. Assoc. 33:264,266,268,270. control points could and should be documented. In the 21. Hawthorn, J. 1967. The organization of quality control. Pages 1-31. future, the foodservice administrator may be required to In S. M. Herschdoerfer, Quality control in the . file reports of self-inspection with State or local Academic Press, New York. 385 pp. regulatory officials. Reports would be monitored by a 22. Hill, M. A., and G. Glew. 1974. Recipe development. Hospitals, regulatory official and periodically validated by inspec­ J.A. H.A. 48(12):124-126. 23. Ito, K. 1974. Microbiological critical control points in canned tion. The FDA is now in the process of developing a foods. Food Techno!. 28(9):46, 48. Model Food Service Ordinance that will be available and 24. Kauffman, F. L. 1974. How FDA uses HACCP. Food Techno!. promoted for State and local adoption to regulate and 28(9):51, 84. inspect foodservice establishments (7). 25. Kramer, A., and B. A. Twigg. 1970. Quality control for the food industry. Volume 1 - Fundamentals. The Avi Publishing Co., Inc., Westport, Connecticut. 556 pp. REFERENCES 26. Litsky, B. Y. 1973. Food service sanitation. Modem Hospital Press, 1. AHA 1972. Food service manual for health care institutions, 3rd Chicago. 230 pp. ed. American Hosptial Association, Chicago. 312 pp. 27. Longree, K. 1972. Quantity food sanitation, 2nd ed. Wiley­ 2. Angelotti, R. 1975. FDA regulations promote quality assurance. Interscience, New York. 422 pp. Food Techno!. 29(11): 60,62. 28. Longree, K., and G. G. Blaker. 1971. Sanitary techniques in 3. Bauman, H. E. 1974. The HACCP concept and microbiological food service. John Wiley and Sons, Inc., New York. 225 pp. hazard categories. Food Techno!. 28(9):30,32,34,74. 29. Miller, E. J. 1964. Quality- a magic formula? J. Amer. Dietet. 4. Blaker, G., J. L. Newcomer, and E. Ramsey. 1961. Holding Assoc. 45:347-350. temperatures needed to serve hot foods hot. J. Amer. Dietet. Assoc. 30. NAS. 1969. Classification of food products according to risk. An 38:455-45 7. evaluation of the problem. Pub. No. 1683. National 5. Blaker, G., and E. Ramsey. 1961. Holding temperatures and food Academy of Sciences, Washington, D. C. 207 pp. quality J. Amer. Dietet. Assoc. 38:450-454. 31. Pasch, J. A. 1974. Food and other sources of pathogenic micro­ 6. Bobeng, B. J. 1976. Hazard analysis critical control point models organisms in hospitals. A review. J. Milk Food Techno!. 37:487-493. for quality control of entrees in hospital foodservice systems. 32. Peterson, A. C., and R. E. Gunnerson. 1974. Microbiological Unpub. Ph. D. Thesis, Univ. of Wis., Madison. critical control points in frozen foods. Food Technol28(9):37-44. 7. Bower, W. F., and A. S. Davis. 1976. The federal food service 33. Richardson, T. M. 1969. Sanitation for food service workers. program. J. Milk Food Techno!. 39:128-131. Institutions Magazine, Chicago. 116 pp. 8. Bryan, F. L. 1974. Microbiological food hazards today- based 34. Silverman, G. 1976. Microbiology of mass feeding systems: an on epidemiological information. Food Techno!. 28(9):52,54,58,59- introduction. J. Milk Food Techno!. 39:196. 60,62,64,66,84. 35. Smith, C. A., Jr., and J.D. Smith. 1975. Quality assurance systems 9. Bunch, W. L., M. E. Matthews, and E. H. Marth. 1976. Hospital meet FDA regulations. Food Techno!. 29(11):64,66,68. chill foodservice systems: acceptability and microbiological 36. Stauffer, L. D. 1964. Safe food handling requires health-conscious characteristics of beef-soy loaves when processed according to food handlers. Hospitals, J.A.H.A. 38(18):88, 91-92, 94, 97. system procedures. J. Food Sci. 41:1273-1276. 37. Stauffer, L. D. 1971. Sanitation and the human ingredient. 10. Corlett. D. A .. Jr. 1973. Freeze processing: prepared foods, Hospitals. J .A.H.A. 45(13):62-65. seafood, onion. and potato products. Presented at the HACCP 38. West, B. B., L. Wood, V. F. Harger, and G. S. Shugart. 1977. Inspector Training Course, FDA, August 9. 19 pp. Food service in institutions, 5th ed. John Wiley, New York. 839 pp.