bluuebunny/crossref_metadata_2025_split huggingface dataset:
METHODS FOR THE QUALITATIVE AND QUANTITATIVE DETERMINATION OF AFLATOXINS1
Authors: Marth E. H. 
Published: December 2016

Summary
Qualitative and quantitative measurements of aflatoxins are most often routinely made by means of thin-layer chromatography. The accuracy of the quantitative determination by this procedure can be improved by substituting a densitometric “reading” of the thin-layer plates for visual examination. Examination of small samples (down to 0.3 mg) can be accomplished by a modified thin-layer chromatography procedure which employs an acetone-water extraction technique. Confirmation of toxicity is most often done with the duckling bioassay although embryonated chicken eggs have been used successfully for this purpose. Other methods which, under certain circumstances, may find application in the measurement of aflatoxins include: paper chromatography, microbiological assay, spectrophotometry, and a tissue culture assay.
THE FATE OF SALMONELLAE IN THE MANUFACTURE OF COTTAGE CHEESE
Authors: McDonough F. E. , Hargrove R. E. , Tittsler R. P. 
Published: December 2016

Summary
The effects of cooking temperatures ranging from 110 to 130 F on the fate of salmonellae during the manufacture of Cottage cheese were determined. Seven test species noted for heat resistance and occurrence in dairy products were used to inoculate cheese milk. Salmonellae determinations were made on the milk, whey, curd and cheese at varying stages of manufacture. Salmonellae survived at 110 and 115 F in all trials, and at 120 F in 1 of 5 trials. None survived at 125 F. Creamed Cottage cheese was inoculated with salmonellae, stored at 40 F and analyzed periodically. No marked decrease in numbers was observed during storage.
USE OF A MODIFIED MILK QUALITY TEST ON REFRIGERATED MILK AND COMPARISON WITH OTHER MASTITIS TESTS1
Authors: Elliott L. P. 
Published: December 2016

Summary
The milk quality test (MQT) was found to be inadequately sensitive for testing milk after overnight refrigeration. It was adapted, however, so it could be used on refrigerated milk. It proved to be a fast, simple and accurate indirect test for mastitis that compared quite well with other known mastitis tests.
QUALITY CONTROL PROGRAMS OF MILK MARKETING COOPERATIVES IN THE UNITED STATES1
Authors: Freeman T. R. , Randolph H. E. 
Published: December 2016

Summary
Replies were received from 63 of 123 cooperatives surveyed. The smallest cooperatives were located in the Western region and the largest in the North Atlantic region. There was no relationship between the size of the organization and the number of fieldmen employed per 100 members or per million pounds of milk produced. Of the 57 cooperatives employing fieldmen, 45 reported that 50% or more of their fieldmen's time was devoted to raw milk quality problems. Opinion was divided about equally as to whether raw milk quality problems should be the responsibility of the cooperative, or jointly of the plant, the cooperative, and the regulatory agency. A great diversity was found in the frequency and method of evaluating raw milk quality by the cooperatives. Eighteen basic types of tests were used, with tests for inhibitors and total bacteria counts being the most popular.
THE USE OF THE 0.01 ML LOOP IN THE PLATE LOOP METHOD FOR MAKING VIABLE COUNTS OF MILK1
Authors: Thompson D. I. , Black L. A. 
Published: December 2016

Summary
A-plate loop count method for determining viable counts of pasteurized milk products is described. The technique uses a 0.01 ml calibrated platinum alloy loop attached to a continuous pipetting syringe for rinsing the 0.01 ml of sample into a petri dish with 1 ml of sterile buffered dilution water prior to pouring with agar. Results with this method indicate that accuracy within ± 15 percent is attainable on samples of skim, 2 percent, homogenized, whole milk, and half and half. Measurements of chocolate milk were not accurate.
IMPROVING THE BACTERIOLOGICAL QUALITY OF CHICKEN FRYERS1,2
Authors: Keel J. E. , Parmelee C. E. 
Published: December 2016

Two commercial fryer processing operations were investigated to determine the bacteriological quality of the fryers during and after evisceration. Alterations of washing, rinsing, and chilling methods were made to reduce bacterial numbers on skin surfaces of fryers. Swab samples were collected from fryer skin surfaces at various points in the processes and from table surfaces. Total plate counts, psychrophile counts, and coliform counts were determined.
Total plate counts provided the greatest amount of useful information. Coliform counts were not suitable indicators of bacteriological conditions in the evisceration process.
The major sources of bacteria on the skin surface of chilled fryers were the skin of freshly picked fryers and contamination added during the transfer of carcasses from the picker to the evisceration line. Evisceration of the fryers did not add significant numbers of bacteria to the skin surface. Bacteria on the skin of freshly picked fryers were firmly affixed to the surface. They could be removed in increased numbers by combining increased volumes of wash water with the scrubbing action of flexible rubber fingers in the washer.
FLOW CHARACTERISTICS IN HOLDING TUBES OF COMMERCIAL EGG PASTEURIZERS
Authors: Kaufman V. F. , Ijichi K. , Putnam G. W. 
Published: December 2016

Fluid flow theory, as related to the holding of egg products in continuous pasteurization operation, is discussed. The conditions for laminar, turbulent and transitional types of flow; the specific factors in holding tubes that may cause deviations from the anticipated type of flow; and the effects of the viscosities of egg products are outlined. Retention times for laminar flow and the effects on survival of microorganisms are evaluated.
Determination of minimum holding times in 10 commercial holding tube arrangements with varying egg products were made. All minimum holding times were appreciably less than average holding times but more than would be predicted from simple laminar flow theory. Holding tube efficiencies varied roughly from 60 to 80%. They increased slightly with increased Reynolds numbers over the range of the latter that is found in commercial holding tubes.
CORRELATION OF FOUR MASTITIS DETECTION TESTS WITH RESPECT TO THE LEUCOCYTE COUNT
Authors: Jensen Christen , Beck Lyle D. 
Published: December 2016

A descending order of correlation with respect to the Microscopic Leucocyte Count was obtained as follows: Feulgen-DNA &gt; California Mastitis Test &gt; Modified Whiteside Mastitis Test &gt; Strip Tray Test.
The average overall sample per cow and the composite sample correlations were statistically significant at the 1% level of significance, but many individual composite relationships were not significant. The bulk tank correlations, which represent the entire herd, were not significant. Results indicate that intermixing of raw milk from different sources lowered the concentration of reactive nuclear material to such a level that it was not measurable by the mastitis screening tests employed in these trials.
A COMPARISON OF DIRECT PLATING AND ENRICHMENT METHODS FOR DETECTION AND ENUMERATION OF COAGULASE-POSITIVE STAPHYLOCOCCI IN FROZEN FEEDS OF ANIMAL ORIGIN1
Authors: Chou C. C. , Marth E. H. 
Published: December 2016

Direct surface plating on five selective and differential agar media and enrichment prior to plating were compared for detection and enumeration of coagulase-positive staphylococci in frozen feeds. The enrichment medium was trypticasc soy broth (TSB) fortified with 8, 10, and 12% sodium chloride. In general, direct plating on mannitol salt (MS) and staphylococcus 110 (S110) agars was accompanied by a higher recovery of coagulase-positive staphylococci than was obtained with tellurite polymyxin egg yolk (TPEY), Vogel-Johnson (VJ), and tellurite glycine (TG) agars. Suspected colonies picked from TPEY agar were most likely, and from TG agar were least likely, to be coagulase-positive staphylococci.
Enrichment for 24 hr in TSB containing 8 or 10% sodium chloride yielded more staphylococci than did direct plating on TPEY or TG agars. Numbers obtained by the two procedures usually were more nearly equal when MS or S110 agars were used for direct plating. Enrichment in TSB containing 12% sodium chloride or incubation of broths for 48 instead of 24 hr, even if they contained 8 or 10% sodium chloride, were detrimental to the recovery of coagulase-positive staphylococci. Of the plating media tested, MS, TG, and VJ agars regularly and uniformly recovered coagulase-positive staphylococci from enrichment broths inoculated with highest dilutions of test samples. In contrast to this, erratic results were obtained when S110 and TPEY agars were used to recover these bacteria from the same broth cultures.
Tests on feed-grade frozen meat by-product revealed the presence of 103 to 104 coagulase-positive staphylococci per gram in two samples and 104 to 105 per gram in two other samples. Examination of feed-grade frozen liver indicated the presence of 103 to 104 coagulase-positive staphylococci in one sample and 104 to 105 per gram in two samples.
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.
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.
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.
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.
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.
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.
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.
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&lt;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.