bluuebunny/crossref_metadata_2025 huggingface dataset:
EFFECTS OF TIME AND TEMPERATURE OF GRADE-A RAW MILK SAMPLE STORAGE ON BACTERIAL TEST RESULTS1
Authors: Hartley J. C. , Vedamuthu E. R. , Reinbold G. W. , Clark W. S.
Published: December 2016

Milk produced on 30 grade-A farms was analyzed bacteriologically after the following storage treatments: less than 2 hr; 3.3 and 7.2 C for 1, 2, and 3 days, and 3.3 C for 54 hr followed by preliminary incubation at 12.8 C for 18 hr. The effects of these storage treatments were determined with the following bacterial tests: Standard Plate, thermoduric, coliform, total, psychrophilic, and enterococcus counts.

The Standard Plate and total counts showed essentially the same response to sample storage. Preincubation and storage at 7.2 C for 3 days were the only storage treatments that caused a marked change in the counts; with these treatments, the numbers more than doubled. The coliform count response to storage was similar to that of the Standard Plate and total counts, except coliforms decreased when the sample was stored at 3.3 C. The psychrophilic count showed the most marked increase, of any of the tests, to sample treatments. After storage for 1 day, the psychrophiles increased, especially at 7.2 C; there was more than a 10-fold increase during storage at 7.2 C for 3 days and during preliminary incubation. The thermoduric and enterococcus counts did not change a statistically significant amount during sample storage.

These results emphasize the importance of maintaining milk at temperatures of 3.3 C or below and not attempting to hold milk too long. The potential spoilage problem that psychrophiles may present is shown.
DETECTION OF LEAKS IN THE REGENERATION SECTION OF EGG PASTEURIZERS
Authors: Kaufman Vern F.
Published: December 2016

A method is proposed for the detection of leaks in the heat transfer surface of the regeneration section of an egg pasteurizer. When the unit is not in use, the raw side of this section is pressurized with a fluorocarbon refrigerant gas and air on the pasteurized side is then checked with a halogen leak detector for the presence of fluorocarbon. Laboratory tests indicate that presence of a hole too small for any flow of egg white under normal conditions can be detected. Some information is given on the flow of egg whites, air, and fluorocarbon gas through small holes. The problem of assuring that holes will not be plugged when tests are made was extensively investigated. Conditions required to use the method, based on laboratory tests, are indicated. The test method appears to offer a positive and practical means to determine presence of leaks in the regeneration section that might permit flow of raw to pasteurized product.
MICROTITER METHOD FOR ENUMERATING VIABLE BACTERIA IN MILK
Authors: Fung Daniel Y. C. , LaGrange William S.
Published: December 2016

A rapid microtiter method was investigated as a means of evaluating viable bacterial cells in milk samples, using the conventional Standard Plate Count method as a comparison. Statistical analyses showed high correlation between the two methods. The advantages of this new method are: (a) the ability to analyze many samples simultaneously and (b) savings of time, space, material, and labor. The practical application of this new method in dairy products was shown by a study of bacterial growth during refrigerated storage of milk.
IMPROVED PROCEDURES FOR MEASUREMENT OF AFLATOXINS WITH THIN LAYER CHROMATOGRAPHY AND FLUOROMETRY1
Authors: Shih C. N. , Marth E. H.
Published: December 2016

Optimal resolution of aflatoxins B1, B2, G1, and G2 was obtained when thin layer Chromatoplates equipped with a 0.25 mm layer of silica gel (Adsorbosil-5) were used within 2 hr after heat activation and when plates were developed in an unlined unequilibrated tank containing methanol and chloroform (1:99 v/v). Plates were further improved for fluorometric scanning by extending the distance of the solvent front from 15 to 18 cm and by scoring the Adsorbosil-5 to provide narrow bands prior to spotting the sample. Chromatoplates treated as described were accurately scanned with a fluorometer (not a modified densitometer) and concentrations of aflatoxins were indicated by areas under peaks as drawn by an attached recorder. A satisfactory linear relationship was obtained between the emitted fluorescences expresed as the area under peaks and concentration of the four aflatoxins.
A MICROBIOLOGICAL EXAMINATION OF MUSCLE TISSUE OF BEEF, PORK, AND LAMB CARCASSES1
Authors: Vanderzant C. , Nickelson R.
Published: December 2016

A microbial examination was made of muscle tissue of beef, pork, and lamb carcasses. Samples were taken shortly after death and after 3 days of storage at 1 C. A majority of the samples did not yield isolates on blood agar plates. The following microbial types were isolated: Staphylococcus, Micrococcus, Sarcina, Streptococcus, coryneforms, Bacillus, Clostridium, Flavobacterium, Pseudomonas, Moraxella, Alcaligenes, Acinetobacter anitratum (Herellea), and yeasts and molds. Staphylococci were predominant among the isolates obtained from the three species. A large percentage of the staphylococci were coagulase-positive. Coryneforms also predominated in the lamb and beef samples. Warm muscle samples yielded a greater number of bacterial isolates than chilled Samples. No psychrophilic bacteria were recovered from the samples.
SHELF LIFE AND CULINARY PROPERTIES OF THAWED FROZEN PASTEURIZED WHOLE EGG
Authors: Vadehra D. V. , Steele F. R. , Baker R. C.
Published: December 2016

Commercially pasteurized whole egg had a shelf life (total viable count slightly in excess of 106 bacteria per gram) of approximately 15, 9, 2, and 1 days at 2, 7, 13, and 23 C, respectively. The thawed frozen pasteurized product has a maximum shelf life of 9 days at 2 C and 3 days at 13 C. The thawing temperature of the frozen product did not influence its shelf life to any great extent. Culinary properties of the fresh, pasteurized and thawed frozen pasteurized egg were very similar.
SOURCES OF SALMONELLA CONTAMINATION OF MEAT FOLLOWING APPROVED LIVESTOCK SLAUGHTERING PROCEDURES1
Authors: Childers A. B. , Keahey E. E.
Published: December 2016

Tissues from animals slaughtered at the university abattoir were sampled to determine the spread of bacterial contamination during slaughter. Salmonellae and coliform organisms were cultured from swabs taken of the equipment before and during slaughter and from various viscera sites during slaughter.

Since salmonellae isolations were expected to be low, coliforms were used as an index of contamination. The study indicated that equipment was satisfactorily sanitized before slaughter and minimal contamination occurred during slaughter except for the viscera pans. Contamination of the viscera and carcass of cattle, swine, and sheep was very high. It was found that the bung-dropping operation is less of a contaminating factor than is generally thought and that washing the carcass after evisceration is probably responsible for the greatest spread of contamination.

Salmonellae were isolated from only two swine. The patter of contamination spread was similar to that of coliforms.
NITRATES IN PLANTS AND WATERS1,2
Authors: Keeney D. R.
Published: December 2016

High concentrations of nitrates in waters have been linked to methemoglobinemia in infants, and nitrates in waters and roughage have long been recognized as one cause of animal health problems. The reactions and sources of nitrogen in the environment are reviewed, and factors affecting the nitrate content of edible foods examined. The impact of changed fertilization practices and waste disposal methods on the nitrate levels in ground water requires intensive investigation. The effect of high nitrates in vegetables on infant health, and methods to minimize the nitrate content of fresh and processed vegetable products should be examined.
NON-LETHAL INJURY AND LIMITATIONS OF RECOVERY OF COLIFORM ORGANISMS ON SELECTIVE MEDIA1
Authors: Maxcy R. B.
Published: December 2016

Cell injury as a factor in the enumeration of coliform bacteria with selective media was evaluated. Non-lethal injury reduced the ability of cells to produce outgrowth. Escherichia coli and Aerobacter aerogenes were equally sensitive. Brilliant green lactose bile broth, desoxycholate lactose agar, and violet red bile agar were similar in inhibitory effect.

Cell injury occurred with sub-lethal heat treatments, exposure to chlorine, exposure to sodium chloride, and freezing and thawing cycles. Circumstances to inflict injury are found in common environmental conditions of the food industry. Presence of injured cells may provide a count with a selective medium that is only 10% of the total count obtained with standard plate count agar. The limiting factor for recovery in selective media was associated with the surfactant.

An understanding of these limitations in the use of selective media in quality control and public health applications of the tests should contribute to proper interpretation of results.
NUTRIENT REQUIREMENTS AND GROWTH CONDITIONS FOR PRODUCTION OF LACTASE ENZYME BY SACCHAROMYCES FRAGILIS1
Authors: Wendorff W. L. , Amundson C. H. , Olson N. F.
Published: December 2016

Lactase enzyme was produced by Saccharomyces fragilis NRRL Y-1109 grown in deproteinized Cheddar cheese whey. Nutrients and growth conditions required for maximum lactase production were determined. Lactose concentration, sources of growth factors; temperature of incubation, and pH of the whey were the primary factors affecting lactase production. Increased levels of lactose in whey stimulated the yeast to produce higher levels of lactase activity per gram of dried yeast. Corn steep liquor was the best source of added growth factors. Yeast grown under optimum conditions, pH 4.0 to 4.7 and 28 C, yielded 175 units per gram of yeast and 1300 units per liter of whey.
EFFECT OF MAGNESIUM CARBONATE AND SODIUM PHOSPHATE ON THE EXTRACTION OF CHLOROPHYLL-LIKE PIGMENTS AFTER THERMAL PROCESSING OF SPINACH PUREE
Authors: Fleischman D. L. , Clydesdale F. M. , Francis F. J.
Published: December 2016

Because buffers are important in maintaining green color in vegetable purees, a study was undertaken to determine if sodium phosphate and/or magnesium carbonate would effect extraction of some or all of the chlorophyll-like pigments in spinach puree and thus interfere with their analysis. Samples were prepared with and without addition of the above additives and pigment analyses were carried out for chlorophylls, chlorophyllides, pheophytins, and pheophorbides. It was found that addition of sodium phosphate and/or magnesium carbonate prior to blanching and processing caused chlorophyll b, pheophytin a, pheophorbide a, and pheophorbide b to be bound to some extent. Pheophytin b was unaffected Chlorophyll a, chlorophyllide a, and chlorophyllide b were present in such small quantities that no conclusions could be drawn about their extractability.

This phenomenon is an important consideration in the analysis of chlorophyll-like pigments in buffered systems and also might supply a suitable means for removal of chlorophyll-like pigments from foods and beverages where the color they impart is undesirable.
BACTERIAL CONTAMINATION IN PROCESSING RABBIT FRYERS1
Authors: Hagen Karl W.
Published: December 2016

Bacterial examinations were made of skin surfaces of rabbit carcasses following several methods of processing. There was a correlation between high bacterial counts and shelf life. Prolonged pre-chilling shortened shelf life. The value of adding ice to chill water was not indicated but 15 ppm chlorine lowered bacterial counts and extended shelf life one day. The types of organisms encountered were micrococci, coliforms, gram-positive bacilli, and pasteurellae.
THE IDENTIFICATION OF CYANIDIN-3-2G GLUCOSYL-RUTINOSIDE IN MONTMORENCY CHERRIES1
Authors: Fischer R. R. , von Elbe J. H.
Published: December 2016

One of the major anthocyanins in Montmorency cherries has been identified as mecocyanin (cyanidin-3-sophoroside). Evidence is presented to show that this anthocyanin is not mecocyanin but rather cyanidin-3-glucosyl-rutinoside. The identification is based on Rf values; partial and complete hydrolysis with strong acid; and infra-red, visible, and ultraviolet spectra.
AFLATOXINS: PRODUCTION ON BEANS AS AFFECTED BY TEMPERATURE AND MOISTURE CONTENT
Authors: Beuchat L. R. , Lechowich R. V.
Published: December 2016

The suitability of dried navy, pinto, and kidney beans as substrates for the support of growth and aflatoxin production by Aspergillus parasiticus was investigated. Inoculated beans adjusted to 20, 25, or 30% moisture were incubated at 21, 28, or 35 C for 1, 3, or 5 weeks. Aflatoxins were produced on all substrates having 25 or 30% moisture when incubation was at 21, 28, or 35 C. Substrates containing 30% moisture and incubated at 28 C supported maximum aflatoxin production. There was a decrease in aflatoxin concentrations after these maxima were reached.
EFFECT OF SOLUTE CONCENTRATION AND PRE-SOIL INTERACTION ON THE MICROFLORA OF DAIRY ORIGIN ON STAINLESS STEEL SURFACES1
Authors: Barnhart H. M. , Maxcy R. B. , Georgi C. E.
Published: December 2016

Use of modern dairy food processing equipment creates a complex microenvironment. Closed systems reduce air drying. The rate and extent of drying are dependent on temperature and humidity of the environment. These factors were studied to determine their impact on the microflora of films of milk on stainless steel surfaces. An ecosystem was established to simulate dairy food equipment by using 1cm2 pieces of stainless steel in controlled humidity chambers. Presoiling water loss from a film of milk, and solute concentration were studied to determine their influence on the fate of the microflora. Temperature and humidity of the atmosphere influenced the rate of moisture loss from films. Pre-soiling reduced the rate of water loss from films of milk sufficiently to allow bacterial growth at 12–80% relative humidity (RH). Results indicate bacteria can grow in a film placed in humidities well below the 95% RH limit previously projected. Apparently the substrate is influenced by interaction of the milk film and the stainless steel surface.
FIELD EVALUATION OF AN OPTICAL SOMATIC CELL COUNTER FOR MILK
Authors: Schultze W. D.
Published: December 2016

The Technicon Optical Somatic Cell Counter (OSCC) was studied for its utility in determining the somatic cell concentration in raw milk. Over the range of 30,000 to 1,600,000 cells per milliliter, dilutions of a milk sample or a stabilized turkey erythrocyte standard elicited a smooth but slightly curvilinear instrument response. Thirty milk samples of cell concentration clustering closely around 1,500,000 cells per milliliter were analyzed in triplicate. From an analysis of variance of the uncorrected instrument readout we computed an LSD.01 of 1.48 major chart scale divisions, which is a sensitivity of 2.0% at 1,500,000 cells per milliliter.

Determinations were made on bulk tank milks ranging from 100,000 to 1,600,000 cells per milliliter. Chart peak values and Direct Microscopic Somatic Cell Counts (DMSCC) were highly correlated (0.96) when operating at either 30 or 60 samples per hour. Apparent inadequacies of the turkey erythrocyte calibration system may account for the discrepancy between the slope of the calibration curve and the regression lines. The discrepancy was much greater at the faster sampling rate. In a comparison of split samples of milk by both OSCC and DMSCC in three laboratories, the OSCC averaged 20% higher than the DMSCC counts but yielded a much lower standard deviation.
EXAMINATION OF FROZEN VEGETABLES FOR SALMONELLAE1
Authors: Splittstoesser D. F. , Segen Barbara
Published: December 2016

Salmonellae detection methods developed for other foods were not entirely satisfactory for frozen vegetables because of the presence of slow lactose-fermenting organisms that resembled the pathogens on various differential media. The problem was solved by raising the incubation temperature of brilliant green agar to 42 C. Examination of a number of frozen vegetables, many collected in processing line surveys, failed to uncover salmonellae. Data were obtained that suggested the organisms were inhibited by the normal microflora of frozen vegetables.
MICROBIOLOGICAL CRITERIA IN USDA REGULATORY PROGRAMS FOR MEAT AND POULTRY1
Authors: Elliott R. Paul
Published: December 2016

Whereas food agencies must consider the consumer first, the expertise in microbiology lies instead in the universities, the government, and the industry. Scientists should make a point of showing businessmen many of the aspects of microbiological control that would show an economic advantage. Control of contamination and time-temperature abuse can be related indirectly to health hazard. Control of microbial level maintains natural food flavors. Low microbial level increases the shelf life of chilled products to a marked degree.

The Consumer Protection Programs of the Consumer and Marketing Service (C&MS) have many microbiological control procedures built into them: General sanitation, separation of cooked from raw products, requirement for a midshift clean-up (with a bacteriological monitoring system as an alternative), cooking requirements, and labeling requirements. A recent development is the decision to extend microbiological control to the use of microbiological criteria.

Microbiological criteria can be applied in three ways: first, by picking a figure out of the air. This is, of course, the bad way; second, by determining the general microbiological level in foods in commerce without regard to the effect of processing (this is a better way) and, third, (the best) by determining what is good manufacturing practice and then determining the microbial levels associated therewith. When a microbiological criterion is established, methods for sampling and analysis should be specified. The data both for establishment of microbiological criteria and for establishment of acceptability of given lots should be statistically significant; therefore, it is necessary to know the natural variation of levels of microbial groups within various commodities. As technology improves, it may often be necessary to re-evaluate any criteria in use. If microbiological criteria require drastic changes in an entire industry, they should be applied with great discretion to avoid seriously damaging the industry. On the other hand, those that require changes in the less satisfactory segments of an otherwise satisfactory industry could be applied more promptly.

Consumer and Marketing Service policy on microbiology criteria was reported in detail in the December 20, 1968, issue of the Federal Register. Our group has recently published the Microbiology Laboratory Guidebook, which is available on request.

Heating, adding a chemical, canning, or even freezing could be used to reduce microbial levels to meet a microbiological standard, but this is not satisfactory to the Consumer and Marketing Service.
MICROORGANISMS FROM ARMS AND HANDS OF DAIRY PLANT WORKERS2
Authors: Sunga Fe C. A. , Heldman D. R. , Hedrick T. I.
Published: December 2016

Microorganisms shed into decontaminated air from arms and hands of four dairy plant workers were collected on plates of various selective media using a Casella sampler. Microorganisms selected for identification were representative of the types encountered. Of 256 microorganisms isolated, 55.5% were cocci, 41.4% were rods, and only 3.1% were yeasts. Thirteen species of cocci were identified. Those occurring most frequently were Sarcina flava, Peptococcus prevotii, Sarcina aurantiaca, Sarcina hansenii, and Staphylococcus epidermidis, in decreasing order, of frequency. Eighteen species of rods were observed. Those identified most frequently, in decreasing order, were: Alcaligenes marshallii, Alcaligenes bookeri, Pseudomonas synxantha, Pseudomonas iodinum, Pseudomonas aeruginosa, and Corynebacterium striatum.
BEHAVIOR OF SALMONELLA DURING THE MANUFACTURE AND STORAGE OF A FERMENTED SAUSAGE PRODUCT1
Authors: Goepfert J. M. , Chung K. C.
Published: December 2016

The behavior of salmonellae during the manufacture and storage of Thuringer sausage was studied. Five serotypes of salmonellae behaved in a similar fashion during the fermentation period regardless of whether a Pediococcus sp. or Lactobacillus sp. starter culture was used. The number of salmonellae per gram of sausage emulsion decreased by 0.75 – 2.5 logs during the 18–24 hr of fermentation. Initial experiments indicated that a combination of the acidity that developed and the NaCl present was responsible for the demise of the salmonellae. Sodium nitrite, sodium nitrate, and ascorbic acid had little or no effect on the fate of salmonellae in the fermenting material. When the level of sucrose in the curing salt mixture was reduced to 0.25%, a product with a final pH of 5.2–5.4 resulted. Salmonellae were able to multiply in this sausage emulsion during the course of fermentation.

Heat treatments employing three temperatures (46, 49, 52 C) were evaluated as to their efficiency in destroying salmonellae in Thuringer sausage. The effect of these heat treatments on both ‘normal’ and ‘low acid’ sausage was examined. As expected, the highest temperature was most effective in both instances. Salmonellae were able to multiply in the low acid product while it was being heated at 46 C.

The number of viable salmonellae in finished Thuringer sausage declined during refrigerated storage of the product. The rate of decline was not sufficient to ensure complete destruction of even low levels of contamination.
HEAT RESISTANCE OF ENTEROCOCCI1,2
Authors: Shannon E. L. , Reinbold G. W. , Clark W. S.
Published: December 2016

Fifty enterococcus cultures were exposed to temperatures of 62.8 and 71.1 C for 30 min and 71.7 C for 15 sec in skimmilk containing approximately 10 million cells/mi. Streptococcus durans was most heat resistant, although no culture survived 71.1 C for 30 min. Additional milk solids and fat did not provide protection from destruction by heat. In skimmilk, at population levels of approximately 100/ml, the cultures survived heat treatments of 71.7, 76.7, and 82.2 C for 16 sec by 55.2, 46.4., and 32.5%, respectively.

After pasteurization at 62.8 C for 30 min, only 8 of 426 commercial milk samples had detectable enterococci. These 8 samples contained from 1 to 30 enterococci/ml. When 55 of these more heat-resistant cultures were again laboratory pasteurized, 32 remained viable. Only 8 of these 32 cultures showed numerical increase when stored at 5 to 8 C for 7 days after laboratory pasteurization.

Before enterococci can be used as indices of bacterial quality in dairy products, their presence or absence must be related to the specific heat treatments given dairy products.
EFFECT OF 5′-RIBONUCLEOTIDES ON HEAT-INDUCED OFF-FLAVOR OF HYDROLYZED VEGETABLE PROTEIN
Authors: Sawyer F. M. , Laus Mary Jane
Published: December 2016

The effect of an added mixture of IMP:GMP (1:1) on heat-induced off-flavor in solutions of commercial samples of hydrolyzed vegetable protein (HVP) was evaluated with a trained sensory testing panel using a standard paired comparison method. Samples were prepared with and without addition of nucleotide, vacuum sealed in cans, and heat processed at 250 F for 35 min. In every comparison, the panel was able to detect differences between samples at a very high level of significance, statistically, and indicated that IMP:GMP at 0.005% or 0.01% definitely suppressed apparent intensity of the typical off-flavor of heated solutions of HVP.
A CRITICAL LOOK AT OUR CONSERVATIVE DAIRY INDUSTRY1
Authors: Lane C. Bronson
Published: December 2016

Many feel that the dairy industry is far too conservative, meaning it is reluctant to adapt or change when the need arises. Seven conservative conditions, designated “sacred cows” of the dairy industry, need a major overhaul. These are: outdated recruiting methods and industry image; a reluctance to adopt new testing procedures which could increase milk volume and producer returns, especially for the manufacturing milk industry; conservatism in adopting new testing procedures, with particular reference to the electronic fat-testing devices; segmentation and isolation of industry components; producer thefts by fieldmen functioning as procurement personnel rather than trouble-shooters for farm problems; duplication and non-uniformity of inspections; a low priority for promotion and new product development.

Elimination of the sacred cows could be accomplished by: tearing down prohibitive and conflicting legislative standards; ceasing to push for restrictive and discriminatory legislation which prohibits the manufacture of wholesome food products adopting the Interstate Milk Shipments Agreements; placing more emphasis on market orientation and product promotion; encouraging producers to enroll in herd-testing programs; recruiting industry personnel with zeal and a new image; and accepting and utilizing new testing procedures which can save time and money.
EFFECT OF DILUTION BOTTLE MIXING METHODS ON PLATE COUNTS OF RAW-MILK BACTERIA1
Authors: Huhtanen C. N. , Brazis A. R. , Arledge W. L. , Cook E. W. , Donnelly C. B. , Ginn R. E. , Murphy J. N. , Randolph H. E. , Sing E. L. , Thompson D. I.
Published: December 2016

Forty-six raw milk samples were analyzed for plate counts at 32 C by eight different laboratories; each using three mixing procedures for the initial dilution. These were: five inversions in a 5 sec period, 15 inversions in a 15 sec period, and the “standard” method of twenty-five, 1 ft long, vertical cycles in a 7 sec period. The standard method gave the highest bacterial counts (71.1 × 103/ml average) the 15-15 method was second highest (60.4 × 103/ml average) and the 5-5 method was lowest (57.8 × 103/ml average). The standard method gave significantly higher (P<0.01) bacterial counts than the other two. The inversion methods were not significantly different from each other.

Tests of reproducibility (pooled average variances for each method) did not show any significant differences between mixing methods. There were significant differences in reproducibility between laboratories. There was evidence of interaction between mixing methods by samples and mixing methods by investigators.
THE REFUSE DISPOSAL PROBLEM: PREVENTION COULD BE THE CURE
Authors: Embree Caroline , Schachtmeister Sydney C.
Published: December 2016

Production of solid waste in the United States is beginning to outrun disposal capacity. Solid waste production must be sharply curtailed; eventually there will be no adequate alternative. Means to achieve reduction include: reinstating returnable bottles and creating returnable cans, recycling metals, paper, plastics and cans, banning heavy newspaper advertising and advertising by mail, giving up large paper grocery bags, regulating packaging to reduce waste, developing biodegradable containers for frozen and convenience foods, and returning from “planned obsolescence” to easily available parts and repairs. Financial incentives built into the reduction measures and sophisticated advertising techniques will be needed to gain the cooperation of the public.
ELECTROMETRIC pH DETERMINATIONS OF DIFFERENT AGAR MEDIA AT 25 AND 45 C
Authors: Walter William G. , Kuehn Karen , Boughton Alice
Published: December 2016

In all tests performed using antibiotic test medium No. 1, APHA standard reference, BBL standard methods, violet red bile, and desoxycholate lactose agars, the overall mean values of pH readings were significantly higher (p<0.01) when determined at 25 C than at 45 C. This difference varied between 0.14 and 0.38 pH unit. Whether this difference has practical significance in routine laboratory use of these media was not determined.
MICROBIAL FLORA OF GULF OF MEXICO AND POND SHRIMP1,2
Authors: Vanderzant Carl , Mroz Eva , Nickelson R.
Published: December 2016

Bacterial counts of shrimp delivered by fishing vessels to processing plants varied greatly. Aerobic plate counts at 28 C ranged from 870–1,300,000 per gram. Either natural seawater or distilled water could be used in media preparation. The use of artificial seawater usually resulted in lower counts. The microbial flora of Gulf shrimp was dominated by coryneforms and species of Pseudomonas, Moraxella, and Micrococcus. Refrigerated storage usually caused an increase in Pseudomonas species. Bacterial counts of pond shrimp were much lower than those of Gulf shrimp. In some samples of pond shrimp Bacillus and Lactobacillus species were pre-dominant.
POLYMYXIN-COAGULASE-MANNITOL-AGAR
Authors: Lee J. S. , Orth D. S. , Anderson A. W.
Published: December 2016

Polymyxin-Coagulase-Mannitol-Agar (PCMA) was compared with three other selective media for the ability to rapidly isolate coagulase-positive staphylococci from frozen shrimp. When spread plating was used, PCMA recovered higher numbers of coagulase-positive staphylococci than did Vogel and Johnson Agar, Staphylococcus Medium No. 110 with 0.75 mM sodium azide, and Trypticase Soy Agar with 10% NaCl. PCMA allowed identification of coagulase-positive staphylococci within 24 hr; whereas, the other selective media required 48 hr for growth plus 24 hr for confirmation of identity of the coagulase-positive staphylococci.

Cross-replica-plating was used to compare the effectiveness of the four selective media studied. In general, PCMA allowed fewer total number of colonies to develop than did the other selective media, but a greater percentage of the colonies that developed on PCMA were coagulase-positive staphylococci.
THE PROBLEM OF RODENTS IN OUR MODERN ENVIRONMENT1
Authors: Penn L. A.
Published: December 2016

Although two species of rats have become thoroughly domesticated and have lived parasitically in man's environment for several centuries, organized urban rat control programs are of comparatively recent origin. A brief history of commensal rats and their relationship to man is presented. Some early urban control programs are summarized. Recent social developments in cities have focused attention on rat control programs and have intensified efforts to free urban areas of rats, particularly in proverty-stricken neighborhoods. An effective community rat control program depends upon motivation and education of citizens as well as enforcement of wisely written rat control ordinances and related solid waste disposal rules. A good rat control ordinance should require rat-proofing of buildings, elimination of rat harborages and sources of food for rats, as well as rat extermination on all premises. For the future, not only will more sophisticated means of citizen motivation be needed, but further studies of the role of sewers and other heretofore neglected areas of rat control in the urban environment.
THE RELATIVE EFFECTIVENESS OF 8-HYDROXYQUINOLINE SULFATE AND ALKYL DIMETHYL BENZYL AMMONIUM CHLORIDE IN THE THE STABILIZATION OF AEROSPACE FOOD WASTE1
Authors: Bourland C. T. , Huber C. S. , Heidelbaugh N. D.
Published: December 2016

The relative effectiveness of 8-hydroxyquinoline sulfate and alkyl dimethyl benzyl ammonium chloride (a quaternary ammonium compound) were compared for their ability to prevent growth of microorganisms in aerospace food waste. Alkyl dimethyl benzyl ammonium chloride and 8-hydroxyquinoline sulfate were added to samples of banana pudding, chicken salad, cocoa, orange drink, and non-fat milk at concentrations ranging from 0.1 to 4%. The rehydrated foods containing the microstatic agents were incubated at 23 C for 60 days.

Microbiological analyses were performed on aliquots which were withdrawn at various intervals. Aliquots were analyzed for total aerobic count, coliforms, yeasts, and molds. No growth was observed in samples containing 8-hydroxyquinoline sulfate in concentrations >1% and stored at 23 C. Coliforms, yeasts, and molds were not detected in the initial food or during the storage period. Research toward a food waste stabilization system which would prevent growth by decreasing the water activity is recommended.
PLASTIC PACKAGES AND THE ENVIRONMENT
Authors: Thomka L. M.
Published: December 2016

Contrary to popular belief and current publicity, most plastics do make good ecological packaging materials. Scientific evidence exists which dispels the stigma of non-disposability and deleterious environmental effects of plastics. Thermoplastics are by nature remeltable and therefore can be recycled by existing conversion methods to other plastic products. Their high energy content and organic composition of mainly carbon and hydrogen make them especially suitable for use in municipal incinerators for drying trash and generating power. Although they are not biodegradable, they do degrade when exposed to outdoor weathering, and they are a suitable and stable landfill material. These benefits must be weighed along with the consumer appeal, sanitary nature, safety, light weight, and protection afforded by plastics when evaluating packaging materials.
BACTERIAL FLORA OF PREFROZEN DRY-CURED HAM AT THREE PROCESSING TIME PERIODS AND ITS RELATIONSHIP TO QUALITY
Authors: Graham P. P. , Blumer T. N.
Published: December 2016

Hams frozen, stored, thawed, and dry-cured were sampled microbiologically after thawing, after curing, and after 30 days aging at about 34.5 C and about 62.5% relative humidity. Selective isolation techniques were made on samples from the surface of the butt, shank, and cushion surfaces and internally from the butt, shank, cushion, knuckle, semitendinosus, and biceps femoris of each ham. Surface samples and intra-muscular shank samples contained the greatest total number of microorganisms. Coagulase-negative Staphylococcus aureus were present in highest numbers at each ham location and at each processing time. The number of microbial cells per gram increased after curing above that in the fresh hams and then decreased generally after aging. No adverse effects on quality were observed and quality appeared unaffected as bacterial numbers changed. Lancefield D group streptococci, Staphylococcus epidermidis, and species of Micrococcus, Proteus, and Bacillus were present in low numbers within the hams. Moisture content appeared to be the limiting factor of bacterial growth; however, salt tolerant microorganisms were the predominant flora. Variations in pH did not appear to influence the microbiology of the hams. Bacteria of public health significance were not isolated on or within the ham tissues.
A NEW TEST TO DETECT LEAD POISONING IN CHILDREN–A SERIOUS ENVIRONMENTAL PROBLEM IN THE INNER CITY1
Authors: Hankin Lester
Published: December 2016

Lead poisoning among children is a serious environmental and public health problem, especially in the inner city. Some children eat paint chips containing lead and thus become poisoned. A rapid screening test based on urinary delta-aminolevulinic acid and using a dipstick to collect samples was devised so that the mother could take the sample herself. The dipstick is composed of a piece of ion exchange paper stapled to a plastic handle. The research leading to the development of this test is discussed relative to overall environmental problems.
CLOSTRIDIUM PERFRINGENS ENTEROTOXIN1
Authors: Hauschild A. H. W.
Published: December 2016

Clostridium perfringens type A food poisoning is caused by ingestion of food contaminated with large numbers of C. perfringens cells. The cells multiply and sporulate in the intestine and produce an enterotoxin in situ. The enterotoxin is released upon cell lysis and causes increased capillary permeability, vasodilation, and excess fluid movement into the intestinal lumen resulting in diarrhea.

Purified C. perfringens enterotoxin has a UV absorption spectrum characteristic for proteins, and is essentially free of nucleic acids, lipids, and reducing sugars. Its apparent molecular weight is 36,000 ± 4,000, its Stokes radius 2.6 nm, and its isoelectric point pH 4.3. Its specific toxicity is about 2,000 mouse MLD/mg N.
III. LIPOLYTIC ACTIVITY1
Authors: Angeles Antonieta Gaddi , Marth E. H.
Published: December 2016

The following lactic acid bacteria, when tested with the agar-well method, were able to hydrolyze tributyrin and triolein, but not soybean oil: Streptococcus lactis, Streptococcus cremoris, Streptococcus diacetilactis, Streptococcus thermophilus, Leuconostoc mesenteroides, Pediococcus cerevisiae, Lactobacillus delbrueckii, Lactobacillus casei, Lactobacillus pentosus, and Lactobacillus brevis. Tributyrin only was hydrolyzed by Lactobacillus helveticus. Some free fatty acids were liberated by L. casei, L. delbrueckii, and S. thermophilus in soymilk (1.9% soybean lipids) and in MRS broth fortified with 2.0% soybean oil during a 14-day period of incubation. Although L. casei and L. delbrueckii were more active in soymilk than was S. thermophilus, they released about 10% of the amount of free fatty acids liberated by Candida lipolytica during a similar incubation period.
THE DIRECT MICROSCOPIC SOMATIC CELL COUNT AS A SCREENING TEST FOR CONTROL OF ABNORMAL MILK1
Authors: Schultze W. D. , Smith J. W. , Jasper D. E. , Klastrup O. , Newbould F. H. S. , Postle D. S. , Ullmann W. W.
Published: December 2016

The Direct Microscopic Somatic Cell Count can be used advantageously in control of abnormal milk to perform simultaneously screening and confirmation of milk samples. Confidence limits computed according to the individual microscope Strip Factor are used to interpret the count made on a single strip of one of the two milk films. The sample is assigned on the basis of the interpreted count to one of three categories: (a) less than the legal cell concentration maximum ( P <0.05); (b) in the region of the cell concentration maximum and thus subject to confirmation; or (c) greater than the legal cell concentration maximum (P <0.05). For samples in categories (a) or (c) no further counting is required to accept or reject the milk. For samples in category (b), the four-strip confirmatory count may be completed immediately.
CHANGING PATTERNS IN FOOD PRODUCTION AND PROCESSING
Authors: Calbert Harold E.
Published: December 2016

With the exception of meat packing plants the trend is to fewer but larger production and processing units. Meat packing plants are becoming smaller but more specialized. The broiler industry is producing about 3 billion birds per year. Ten percent of this production is marketed as the ready-to-eat product.

Per capita consumption of most dairy products except cheese and fluid nonfat and low-fat milks is declining. Milk cow numbers will drop to about 11.5 million by 1975 when the nation's annual milk production will be about 114 billion lb. Milk production per cow will continue to increase. There are about 400,000 dairy farms in the U.S. at present compared to 2 million 20 years ago. Large regional milk marketing associations are being organized. Within a few years they will market about 80% of the nation's milk supply. Imitations will continue to plague the dairy industry, but new uses will be found for milk constituents as ingredients in other foods.

Consumption of fresh fruits and vegetables is declining with an increase in per capita consumption of frozen and processed products. Winter production of fresh products for the U.S. market is shifting to Mexico. Unless production of a fruit or vegetable can be completely mechanized, the variety will disappear from the retail market.

High lysine corn has not had good acceptance as a human food. New rice varieties offer hopes for increasing human food supplies. However, their production requires liberal amounts of fertilizer and different farming practices.

New foods will be developed using a combination of plant and animal ingredients. The food industry must find new methods to reduce and handle liquid and solid wastes and must exercise greater control and discretion in the use of agricultural chemicals.
IV. PROTEOLYTIC ACTIVITY1
Authors: Angeles Antonieta Gaddi , Marth E. H.
Published: December 2016

Three methods were examined for their suitability to measure proteolysis brought about by microbial activity in soymilk. The Anson (or Hull) method, a colorimetric measurement of tyrosine and tryptophan, was not able to measure changes detectable by other methods and hence did not appear applicable for this work. Determination of non-protein nitrogen (NPN) to follow proteolytic changes in soymilk was feasible but was time- and labor-consuming. Dye-binding methods were found most workable.

Lactobacillus delbrueckii and Streptococcus thermophilus exhibited proteolytic activity in soymilk but Lactobacillus casei did not. Two other microorganisms, Bacillus cereus and Micrococcus conglomeratus, and rennet were comparatively more proteolytic in soymilk than the lactic cultures.
RELATIONSHIPS BETWEEN WEATHER FACTORS, SOURCE OF SAMPLE, COMPOSITION OF MILK, AND FREEZING POINT DEPRESSION
Authors: Demott B. J.
Published: December 2016

Changes in composition of milks from individual cows did not always respond to differences in atmospheric conditions to the same extent as did herd milk. Milk from individual cows tended to have a lower chloride concentration because of conditions related to wet bulb temperature than did herd milk. Caution should be used in translating results from individual cow's milk to herd milk.
FECAL CONTAMINATION OF FRUITS AND VEGETABLES DURING CULTIVATION AND PROCESSING FOR MARKET. A REVIEW1
Authors: Geldreich Edwin E. , Bordner Robert H.
Published: December 2016

Bacteriological data collected from various field studies involving irrigation water, field crops, and soils were studied with respect to sources and magnitude of fecal contamination associated with cultivation, harvesting, and marketing of fruits and vegetables. Other reports concerned with contamination during agricultural activities were reviewed. Fecal coliform densities proved to be a better measurement of the probable occurrence of waterborne pathogens than any single test for a specific pathogenic group. When the fecal coliform density per 100 ml was above 1,000 organisms in various stream waters, Salmonella occurrence reached almost 100 per cent frequency. These data support the establishment of the proposed limit of 1,000 fecal coliforms per 100 ml of irrigation water, but approved sanitation practices must accompany (or supplement) use of this bacteriological standard. A concept of multiple safeguards to limit the public health hazard associated with poor quality irrigration water, irrigation farming practices, and market preparation of produce is discussed from the microbiological viewpoint.
EFFECT OF PASTEURIZATION ON THE DIRECT MICROSCOPIC COUNT OF EGGS
Authors: Hall H. E. , Brown D. F. , Read R. B.
Published: December 2016

When pasteurized whole eggs from breakers were examined by the Direct Microscopic Count (DMC) procedure, the bacterial count frequently appeared to be too low to correlate with the observed state of decomposition. The DMC of whole egg was found to decrease during pasteurization. To determine why, DMC's were done using the North Aniline Oil - Methylene Blue Stain and the Levowitz-Weber modification of the Newman-Lampert stain. Total bacterial counts also were made using the Petroff-Hausser counting chamber. Results indicated that the reduction in count resulted from lysis of some of the bacterial cells in egg rather than to loss of stainability. Crystalline lysozyme at the concentration found in egg and whole egg preparations produced similar reductions in the DMC of bacteria isolated from egg.
COLLABORATIVE STUDY OF CONFIRMATORY TESTING PROCEDURES FOR SOMATIC CELLS IN MILK
Authors: Read R. B. , Bradshaw J. G. , Peeler J. T.
Published: December 2016

Collaborative studies were done to establish the experimental error (replicate variance) and the among-analyst variance of three modifications of the Direct Microscopic Somatic Cell Count and the Electronic Somatic Cell Count when used in laboratories that test milk routinely. The lowest total variance of logarithms of 0.00639 was obtained with the electronic procedure, followed by 0.00964 for the field counting modification of the Direct Microscopic Somatic Cell Count. The strip-reticle modification of the latter procedure had a total variance of 0.01251, and the Direct Microscopic Somatic Cell Count modification that involves counting all somatic cells on one strip without the use of a reticle had a variance of 0.03041. The coefficients of variation for the experimental error for the Electronic Somatic Cell Count and for the field counting, strip count with reticle, and strip count without reticle modifications of the Direct Microscopic Somatic Cell Count were 8, 17, 14, and 17%, respectively.
USE OF YEAST BETA-GALACTOSIDASE IN MILK AND MILK PRODUCTS1
Authors: Wendorff W. L. , Amundson C. H. , Olson N. F. , Garver J. C.
Published: December 2016

Experiments were carried out to study factors affecting the enzyme activity of β-galactosidase of Saccharomyces fragilis NRRL Y-1109 in milk products. Both the type of lactose-containing substrates and their method of preparation greatly affected β-galactosidase activity. Lactose in an aqueous solution was hydrolyzed more easily than it was in milk products. Of milk products tested, whey was the best substrate for the enzyme. Milk solids, other than lactose, exhibited some inhibitory effect on hydrolysis of lactose by the S. fragilis β-galactosidase. The maximum rate of hydrolysis in milk products was obtained when milk or whey was fortified with 0.1 M potassium sulfate and 10−4 M manganese chloride.

Nonfat dry milk and whey powders, in which portions of the lactose were hydrolyzed to simple sugars, were prepared. These products were of good flavor, appearance, and stability.
CHARACTERIZATION OF BETA-GALACTOSIDASE FROM SACCHAROMYCES FRAGILIS1
Authors: Wendorff W. L. , Amundson C. H.
Published: December 2016

Studies were made on physical and chemical characteristics of β-galactosidase in cell-free extracts of Saccharomyces fragilis Y-1109. The enzyme was stable at pH 6.0–7.0. When frozen in buffer solution, it was stable for more than 3 months but at 51 C, it lost 96% of the activity in 10 min. The optimum pH for lactose hydrolysis at 37 C was 6.5.

The enzyme was activated by K+ while Mn++ served as the cofactor for the enzyme. Manganese appeared to be important in maintaining the integrity of the secondary and tertiary structure of the enzyme molecule. Inactivation of the enzyme by urea indicated the importance of secondary and tertiary structure in the enzymatic function of the yeast β-galactosidase.

Beta-galactosidase appeared to be a sulfhydryl enzyme since heavy metals, p-chloromercuribenzoate, and iodoacetate inhibited the enzyme. Cysteine and galactose were competitive inhibitors of the enzyme, whereas glucose and various amines were non-competitive inhibitors.
EFFECT OF POTASSIUM SORBATE ON YOGURT CULTURES1
Authors: Hamdan I. Y. , Deane D. D. , Kunsman J. E.
Published: December 2016

The effect of 0.05 and 0.10% potassium sorbate on acid and acetaldehyde production and growth of three commercial yogurt cultures was studied. Either amount of potassium sorbate retarded growth of both Lactobacillus bulgaricus and Streptococcus thermophilus strains in the commercial cultures and also decreased the rate of acid production of cultures incubated at 45 C. Acetaldehyde in these cultures decreased during storage and decreased more in samples containing potassium sorbate. In all trials 0.1% potassium sorbate had a greater effect than 0.05% on the above characteristics of the yogurt cultures.
PRODUCTION OF AFLATOXIN IN PRE-PACKAGED LUNCHEON MEAT AND CHEESE AT REFRIGERATOR TEMPERATURES1
Authors: Oldham L. S. , Oehme F. W. , Kelley D. C.
Published: December 2016

Information is lacking on the ability of the common mold contaminant, Aspergillus flavus, to grow and produce aflatoxin in perishable foods at normal refrigerator temperatures. Because of public health interests we investigated the possibility of certain perishable foods contaminated with the mold developing an aflatoxin concentration under conditions of refrigeration.

Cheddar cheese and luncheon-meat samples were inoculated with A. flavus ATCC 15517 and were refrigerated for 12 days at 4.4 or 7.2 C or incubated at 25 C for 12 days, Uninoculated cheese and meat samples were handled in the same manner. All samples were quantitatively analyzed by thin-layer chromatography for presence of aflatoxin.

All samples; except those inoculated and incubated at 25 C, were negative for aflatoxin production. This indicated the mold would, not produce detectable aflatoxin in the tested foods when kept at normal refrigeration temperatures for 12 days.