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M T Bartram

Bio: M T Bartram is an academic researcher from Food and Drug Administration. The author has contributed to research in topics: Organoleptic. The author has an hindex of 2, co-authored 2 publications receiving 14 citations.
Topics: Organoleptic


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Journal ArticleDOI
TL;DR: The usefulness of microbiological standards for frozen foods is now a controversy in the trade and scientific literature, and most reviewers have given arguments both for and against, and have concluded that they should be applied with great caution.
Abstract: The usefulness of microbiological standards for frozen foods is now a controversy in the trade and scientific literature. Most reviewers have given arguments both for and against, and have concluded that they should be applied with great caution. Such standards have the advantage of putting questions of safety on a convenient numerical basis. Canadian workers have reported that promulgation of standards has invariably raised the hygienic level of the products controlled. Bacteriological standards have often been associated with the question of safety to the consumer. Everyone recognizes that food poisoning bacteria are a potential danger in any food. But many have argued that the history of food poisoning outbreaks from frozen foods is excellent and that there is no need for standards; on the other hand, proponents of standards have pointed to the incomplete investigation and reporting of outbreaks, and have argued that there may be more outbreaks than we realize. They have pointed to laboratory studies that have shown grossly mishandled precooked frozen foods to be truly dangerous. Some have proposed that pathogens should be absent from foods; but others have questioned that a microbiological standard can accomplish this end. Some pathogens, such as Salmonella or Staphylococcus have been shown to be so ubiquitous that their presence in some commercial foods is unavoidable. Also, sampling and analytical methods have been described as inadequate to guarantee that pathogens present will be detected. Some have argued that control at the source is a better way-through inspections of the plant operation, by enforcement of handling codes, or by processing procedures such as pasteurization, which would be more certain to result in a pathogen-free food.A most important part of any of the proposed standards is a "total count" of viable aerobic bacteria. English workers have found that foods causing poisoning outbreaks usually had total viable counts above 10 million per gram. On the other hand, these same workers found Salmonella on meats with very low total viable count. The assumption by many that low total count indicates safety has been shown to be not always true. Furthermore, high counts of nonpathogenic organisms, such as psychrophilic saprophytes would have no public health significance. The relation between bacterial level and quality is open to less controversy. Some authorities have pointed to bacterial level as a measure of sanitation, adequacy of refrigeration, or speed of handling. Others have indicated that to determine which of these factors caused a high count would be impossible with only a total count on the product as a guide. Some investigators have said a high count affects flavor adversely before actual spoilage is evident, and this may be a factor in competition on today's market. It is well established that initial bacterial level will affect the shelf-life of a chilled product. Methods of analysis are more nearly adequate for counts than for pathogens, but they need improvement, and should be clearly specified as part of any bacteriological standard. Foods with high count could sometimes be brought into compliance merely by storing them for a sufficient period frozen, or by heating them slightly. This has been cited by some authors as a disadvantage of bacteriological standards. The enterococci and the coliform group (except Escherichia coli) have been shown to be ubiquitous and therefore should not be used alone to indicate fecal contamination. Although E. coli has greater significance, its source should be determined each time it is found. Various reviewers have expressed the need for caution in the application of standards. The principal precautionary arguments we have found are as follows:1) A single set of microbiological standards should not be applied to foods as a miscellaneous group, such as "frozen foods" or "precooked foods."2) Microbiological standards should be applied first to the more hazardous types of foods on an individual basis, after sufficient data are accumulated on expected bacterial levels, with consideration of variations in composition, processing procedures, and time of frozen storage.3) When standards are chosen, there should be a definite relation between the standard and the hazard against which it is meant to protect the public.4) Methods of sampling and analysis should be carefully studied for reliability and reproducibility among laboratories, and chosen methods should be specified in detail as part of the standard.5) Tolerances should be included in the standard to account for inaccuracies of sampling and analysis.6) At first, the standard should be applied on a tentative basis to allow for voluntary compliance before becoming a strictly enforced regulation.7) Microbiological standards will be expensive to enforce.8) If standards are unwisely chosen they will not stand in courts of law.

60 citations

Book ChapterDOI
TL;DR: In this article, the authors discuss the influence of freezing temperatures on microorganisms and the freezing rate on bacterial growth and the formation of ice crystals that has a more profound and disturbing influence on the bacterial growth.
Abstract: Publisher Summary This chapter is concerned mostly with frozen products with one important exception: ice cream, which has been excluded from this survey because it requires special consideration. It discusses the influence of freezing temperatures on microorganisms and the freezing rate. Temperature alone is not the decisive factor with respect to the degree of destruction. It is the formation of ice crystals that has a more profound and disturbing influence on bacterial growth. The freezing rate has a great influence on the number of bacteria developing before the temperature inhibits further growth. Only a brief summary of some of the most important publications on critical reviews on the death of bacteria at low temperatures has been given in the chapter. The factors influencing the bacterial content of prepackaged frozen foods have been summarized in the following manner: (1) the treatment of the raw product including the number of bacteria originally present in the raw product, the manner and rapidity of handling between harvesting and processing, the processing methods, and the hygienic conditions in factories with machines and equipment, (2) the freezing rate, (3) the amount of oxygen present in the package, (4) the microbiological conditions in packages for frozen foods, (5) the storage temperature, (6) the pH of the product, (7) the presence of osmotic substances in frozen foods, and (8) defrosting. The problem of how bacteria grow and multiply after defrosting a frozen food has been discussed briefly. The purpose of this survey was to collect as much material as possible for estimating the hygienic dangers connected with frozen foods, and to specify under what conditions safety may be considered to the same degree as with other foods in the market.

29 citations

Journal ArticleDOI
TL;DR: The production of frozen egg products has increased rapidly in recent years, due mainly to progress in refrigeration and because they are preferred to shell eggs by bakers and by salad, mayonnaise and candy manufacturers.

22 citations

Book ChapterDOI
TL;DR: This chapter discusses the background dominant spoilage flora, and chemical indicators of microbial spoilage of: chemical indicator of quality for foods with high protein content, chemical indicatorsOf quality for Foods with high fat content, andChemical indicators ofquality for foodsWith high carbohydrate content.
Abstract: Publisher Summary Food quality is largely the sum of the characteristics, which register favorably or adversely on an individual's senses. These characteristics include freshness, flavor, odor, texture, tenderness, consistency, color, size and shape, degree of ripeness, and presence or absence of defects. Nutritive value, chemical residues, and disease-producing organisms are also a part of food quality, although these are not measured by the senses of smell, taste, sight, or touch. When one visualizes a spectrum ranging from good to poor quality, the extremes are easily differentiated. This is not true for the central part of the spectrum, however, especially for products in which the manufacturing process tends to mask differences, as with comminuted foods. When foods become more abundant, standards of quality are likely to be higher and more clearly defined. Quality, which is acceptable in one society may not be in another. Chemical indicators may be the only means of evaluating quality in some foods, as processing methods, such as filtration, preclude the use of conventional methods, such as plate counts. In some foods, indicator compounds may supplement microbiological methods of analyzing food quality, including plate counts, mold counts, rot fragment counts, and direct microscopic counts. The use of chemical indicators assists the manufacturer in producing and maintaining high-quality foods. This chapter discusses the background dominant spoilage flora, and chemical indicators of microbial spoilage of: chemical indicators of quality for foods with high protein content, chemical indicators of quality for foods with high fat content, and chemical indicators of quality for foods with high carbohydrate content.

19 citations