CONTROLLING MICROORGANISMS IN CONFECTIONERY PRODUCTS

Transcription

1 CONTROLLING MICROORGANISMS IN CONFECTIONERY PRODUCTS MARIO P. defigueired02 Farmland Food Services, Inc. A.M.F. O Hare, Illinois Received for Publication March 19, 1979 ABSTRACT The control of raw materials, processing and environment are critical factors in the prevention of microbial contamination in confectionery. Salmonella has been found to be the major hazard in confectionery. Testing for this organism at specific control points provides the best means of quality control. Constant surveillance and good manufacturing practice are the best methods for prevention of contamination. INTRODUCTION The microbiological quality of confectionery products is largely dependent upon the quality of ingredients used and the method of manufacture. Confectionery products are generally low-moisture products whose inherent nature restricts the growth and proliferation of microorganisms. Thus the incidence of microbial contamination in confections, though not completely non-existent is low when compared to that in foods such as meats or egg products. Bacteria have been known to survive in dry food products for long periods of time although they will not grow in them. Destruction of bacteria in confectionery products by heat is extremely slow as it might involve the blending of chocolate liquor with sugar, milk solids, and perhaps cocoa butter. It is therefore very important to control raw materials, the formulation, processing, and environmental and storage conditions. Presented at the Thirteenth Annual Symposium, Control of Microorganisms in Food Processing, Rochester, New York. Sponsored by Western NY Section Institute of Food Technologists and the Institute of Food Science, Cornell University, Ithaca, New York. Present address: Ralston Purina Co., Checkerboard Square, St. Louis, Missouri Journal of Food Quality 2 (1978) All Rights 1979 by Food & Nutrition Press, Znc., Westport, Connecticut 143

2 144 MARIO P. defigueired0 Water Activity (q) One of the most critical factors in candy production is water activity (a,) which is defined as the ratio of vapor pressure of water in a confectionery product to the vapor of free water at the same temperature. It is indicative of the available water to support chemical reactions and microbial growth. It has been pointed out that values less than 0.95 inhibit most pathogens whereas 0.90 prevents growth of most nonpathogens, even though staphylococci may grow at values as low as Yeasts are inhibited at 0.88 even though osmophilic yeasts may tolerate values as low as Molds will not grow at values less than 0.80 even though xerophilic molds will tolerate values as low as 0.65 (Hilker 1976). Composition of Confectionery The composition of the confection will have a definite influence on its spoilage traits. Although the bacterial effects of preservatives, essential oils and certain alcohols are important, these agents in themselves will not eliminate spoilage. Coated creams and soft-centered chocolates can explode when gases accumulate beneath the coating following alcoholic, butyric or lactic fermentations. Alcoholic fermentations could be caused by normal or osmophilic yeasts; butyric fermentations by certain species of Clostridium, Bacillus, Leuconostoc; Lactobacillus species might cause lactic fermentation; and yeasts and molds may cause spoilage in products such as marzipans, fondants and glace fruits (Hilker 1976). CONTROL OF CONTAMINATION From a public health viewpoint, the confectionery industry has an excellent record with only one documented outbreak of food poisoning attributable to ingestion of a confectionery product. However, recalls by the Food and Drug Administration have occurred, generally because of Salmonella contamination. In most foods, pathogenic organisms find their way into the packaged product through the following routes: ingredients, faulty processing, poor handling after processing or from the environment - that is, such sources as people, equipment or air. Raw Materials Raw materials inspection constitutes the first line of defense against contamination in confectionery manufacture. The control of raw

3 CONTROL OF MICROORGANISMS IN CONFECTIONERY PRODUCTS 145 materials must start at the source by ensuring that the ingredient supplier manufactures his product under good manufacturing practices with meaningful surveillance programs. Raw materials should be bought on specification which must include the method of testing and sampling based upon a positive lot identification system. This philosophy was taken into consideration by the Salmonella Committee of the National Academy of Sciences (1971) which provided guidelines based upon 5 categories of risk. The committee does not specify how a representative sample is obtained but only states that sampling must be random and representative. In most cases, the rule of thumb approach of sampling the square root of the number of packages in a lot is used. Most companies are faced with rising costs, hence, the need for the development of an efficient program at minimal cost. Most official procedures are complex and time consuming and too often, the analyst, burdened by the procedures, tends to do too few tests and thus fails to accomplish the purpose of the program. Methodology, theref ore, needs to remain flexible as is seen in sample size specifications. Various organizations have proposed various sample sizes : the Food Protection Committee of the National Academy of Sciences (1971): 25 g; the Food and Drug Administration (1968): 100 g; and the American Public Health Association (1976): 100 g. Research conducted by Gabis and Silliker (1974) under the auspices of the International Commission on Microbiological Specifications of Foods showed that large sample (500 g) composites can be analyzed with sensitivity equivalent to multiple analysis of smaller samples. Such an approach should be considered for better efficiency and lower costs. The type of process control used will depend on the type of product being processed, as well as the nature of the process. Indicator organisms may be used as indices of sanitation but their levels will not necessarily be related to Salmonella contamination. Since Salmonella is the major potential hazard in confectionery products, testing must be directed towards this organism at critical control points in the production process to ensure that this organism will not find its way into the finished product. The fact that negative Salmonella tests are indicated in raw materials does not mean that positive tests may not be obtained if these products are mishandled. Dried egg whites are an excellent example of this possibility. The incoming egg whites might be negative for Salmonella. Nevertheless, Salmonella could be present at levels so low that they could not be detected with the method used. The confectionery manufacturer should remember that negative results are not always definitive. Mishandling of egg whites, for example by reconstituting and holding them at high temperatures could result in a

4 146 MARIO P. defigueired0 previously undetectable low level of Salmonella reaching a detectable level, with concomitant contamination of the finished product. Environmental Factors Next to raw materials, environmental factors provide the next major contribution to the contamination of finished products. Microorganisms can find their way into the finished item through environmental routes such as salvage material, equipment, air or personnel, or through the more evident unsanitary conditions prevalent in the plant. Under conditions conducive to their growth, small numbers of microorganisms may multiply rapidly and enhance the potential spread of contamination in the plant. In confectionery production, in-process material or scrap generated during production is often reused. Obviously as such rework material is in contact with the environment for longer periods, it would more realistically reflect handling procedures and raw material quality than mere analysis of the finished product. It has been shown that a low level testing for Salmonella in the finished product revealed no problem, yet, positive results in the environmental samples led to more extensive testing of the finished product, and further tests revealed that the finished product was indeed contaminated. Regular sampling of salvage material is advisable. If tests carried out on such material prove positive for Salmonella, the source of entry probably resides somewhere in the environment and must be sought out. The finished product should also be exhaustively tested. Environmental samples located in more remote areas should be collected. Examples are air filters, floor samplings, and floor drain swabs. The air supply of a plant is an important consideration. Indiscriminate use of air can transfer contamination from one portion of the plant to another due to the generation of dust. Contaminated air currents can spread contamination to the environment and thus into the finished product. Examination of air filters would reflect the environment. Strict separation of facilities for processed and unprocessed product must always be observed to obviate contamination via air. Positive testing for Salmonella in remote samples must be viewed with alarm and steps taken for its elimination. Silliker and Gabis (1975) have used very successfully cellulose sponge sampling techniques for surfaces. In this technique the surface is flooded with sterile water containing 1% tergitol. The surface is rubbed with a sterile sponge and the latter then placed directly into the enrichment media and analyzed. Equipment must be scrupulously cleaned and protected from recontamination. Since confections are low-moisture products, wet clean up

5 CONTROL OF MICROORGANISMS IN CONFECTIONERY PRODUCTS 147 should be kept to a minimum. If low levels of Salmonella are established in the environment, moisture might be the only element needed to spread the organisms. Vacuum type equipment should be used wherever possible. The design of equipment for easy access to cleaning is important. Hard to clean spots could become focal points for bacterial growth. Any entry of moisture into the premises could contribute towards bacterial growth: examples are steam condensation and drips. People play a key role in the manufacturing process and the human carrier could be responsible for the presence of Salmonella in the processed product. The organism could enter the plant via the skin or clothing of the workman, hence the need for training at all levels to prevent the fostering of practices that could lead to the contamination of the finished packaged product with pathogens. CONCLUSIONS It is plainly evident that to be of ultimate use, any control program must be well-organized and enforced on a continuing basis. Problem situations have been known to arise without any prior indications. Thus, constant surveillance coupled with good manufacturing practices is the best prevention. A system of controls, no matter how sophisticated, would be useless without the continuing support of management. In the final analysis the responsibility of enforcing controls rests with management. REFERENCES GABIS, D. A. and SILLIKER, J. H ICMSF methods studies. 11. Comparison of analytical scheme for detection of Salmonella in high moisture foods. Canadian J. Microbiol. 20, No. 5, HILKER, J. S Confectionery products. In Compendium of Methods for the Microbiological Examination of Foods, (M. L. Speck, ed. ), American Public Health Association, Washington, D.C. National Academy of Sciences An Evaluation of the Salmonella Problem, Washington, D.C. National Academy of Sciences Reference Methods for the Microbiological Examination of Foods, Washington, D.C. SILLIKER, J. H. and GABIS, D. A A cellulose sponge sampling technique for surfaces - A research note. J. Milk Food Technol. 38, No. 9,504. SPECK, M. L. (ed) Compendium of Methods for the Microbiological Examination of Foods, American Public Health Association, Washington, D.C. US. Food and Drug Administration. Bacteriological Analytical Manual, Washington, D.C.