Home About us Contact
|
Home About us Contact | ||
|
|
||
Raw Milk (raw + milk)
Terms modified by Raw Milk Selected AbstractsComparison of the sensitivity of manual and automated immunomagnetic separation methods for detection of Shiga toxin-producing Escherichia coli O157:H7 in milkJOURNAL OF APPLIED MICROBIOLOGY, Issue 6 2002R.D. Reinders Aim:,To determine the sensitivity of methods for detection of injured and uninjured Escherichia coli O157:H7 (E. coli O157) in raw and pasteurized milk. Methods and Results:,Raw milk, pasteurized milk with 1·5% fat content and pasteurized milk with 3·5% fat content were spiked with E. coli O157 at low levels. The samples were enriched in modified tryptone soya broth with novobiocin (mTSBn) at 37°C. Aliquots of the enriched culture were analysed either by manual immunomagnetic separation (MIMS) and culturing on sorbitol MacConkey agar with or without cefixime and potassium tellurite (SMACct or SMAC), or by automated immunomagnetic separation and integrated ELISA (EiaFossÔ). Uninjured E. coli O157 organisms were detected in milk by both methods at 1 cfu 10 ml,1 sample). Injured organisms were detected at levels of about 4 cfu 10 ml,1 sample. Direct enrichment in mTSBn (22 h incubation) showed better sensitivity for injured cells than enrichment in buffered peptone water (BPW, 22 h incubation), or in a two-step enrichment consisting of BPW (6 h, 37°C) and mTSBn (16 h, 37°C), successively. Conclusions:,The methods showed equal sensitivity in that they were both able to detect 1 cfu 10 ml,1 milk sample. Injured organisms can be detected and isolated at a level almost as low as this. A resuscitation step is not recommended for the detection and isolation of injured and non-injured E. coli O157 from milk. Significance and Impact of the Study:,Due to the dilution of contamination in the bulk tank, analysis of milk for the presence of E. coli O157 requires a very sensitive method. Both methods described here are useful for such analysis. [source] Inhibition of bacteriophage K proliferation on Staphylococcus aureus in raw bovine milkLETTERS IN APPLIED MICROBIOLOGY, Issue 3 2005S. O'Flaherty Abstract Aims:, To assess the ability of staphylococcal bacteriophage K to inhibit Staphylococcus aureus in raw milk. Methods and Results:, The ability of bacteriophage (phage) to replicate in milk is important in situations where phage might be used as a therapeutic for bovine mastitis. Phage K was able to replicate normally, leading to elimination of the host culture in milk, which had been previously heat-treated. When raw milk was used under identical conditions, the phages were unable to replicate. Phage adsorption assays were performed and these demonstrated that adsorption of phage was significantly reduced in the raw milk while it was restored in the heat-treated sample (86·50% compared with 99·96% adsorption respectively). When confocal microscopy with a Live/Dead Bac light staining system was employed, it was observed that in raw milk S. aureus formed clusters associated with fat globules, while in heat-treated milk, bacterial agglutination had not occurred. Conclusions:, Raw milk inhibits staphylococcal phage K proliferation. Significance and Impact of the Study:, This observation has implications for the exploitation of staphylococcal therapeutic phage in milk. [source] Comparative evaluation of four decontamination protocols for the isolation of Mycobacterium avium subsp. paratuberculosis from milkLETTERS IN APPLIED MICROBIOLOGY, Issue 3 2001L. Dundee Aims:,Four chemical decontamination protocols for milk were compared with respect to mean percentage recovery of spiked Mycobacterium avium subsp. paratuberculosis, minimum detection limit and ease of application. Methods and Results:,Raw milk spiked with 106 cfu M.a. paratuberculosis was decontaminated prior to culture by: (1) treatment with 0·75% (w/v) hexadecylpyridinium chloride (HPC) for 5 h; (2) and (3) Cornell methods employing brain heart infusion broth containing 0·75% (w/v) and 0·9% (w/v) HPC, respectively; and (4) a C18 -carboxypropylbetaine (CB-18Ô) method. The 0·75% HPC method yielded the highest mean percentage recovery of M.a. paratuberculosis (28·7%) and was capable of detecting the lowest number of cells (30 cfu/40 ml). Conclusions:,Treatment of milk with 0·75% HPC for 5 h was shown to be superior to the other methods for decontaminating milk prior to culture for M.a. paratuberculosis. Significance and Impact of Study:,Certain chemical decontamination protocols are too harsh for application to milk. The ,best' decontamination protocol only recovered a fraction of the M.a. paratuberculosis cells present in a milk sample. [source] Application of real-time PCR for quantitative detection of Campylobacter jejuni in poultry, milk and environmental waterFEMS IMMUNOLOGY & MEDICAL MICROBIOLOGY, Issue 3 2003Chengbo Yang Abstract Campylobacter jejuni is a leading human food-borne pathogen. The rapid and sensitive detection of C. jejuni is necessary for the maintenance of a safe food/water supply. In this article, we present a real-time polymerase chain reaction (PCR) assay for quantitative detection of C. jejuni in naturally contaminated poultry, milk and environmental samples without an enrichment step. The whole assay can be completed in 60 min with a detection limit of approximately 1 CFU. The standard curve correlation coefficient for the threshold cycle versus the copy number of initial C. jejuni cells was 0.988. To test the PCR system, a set of 300 frozen chicken meat samples, 300 milk samples and 300 water samples were screened for the presence of C. jejuni. 30.6% (92/300) of chicken meat samples, 27.3% (82/300) of milk samples, and 13.6% (41/300) of water samples tested positive for C. jejuni. This result indicated that the real-time PCR assay provides a specific, sensitive and rapid method for quantitative detection of C. jejuni. Moreover, it is concluded that retail chicken meat, raw milk and environmental water are commonly contaminated with C. jejuni and could serve as a potential risk for consumers in eastern China, especially if proper hygienic and cooking conditions are not maintained. [source] Milk yields, physico-chemical properties and composition of milk from indigenous Malawi goats and their Saanen half-bredsINTERNATIONAL JOURNAL OF CONSUMER STUDIES, Issue 3 2003P.P. Mumba Abstract A study to compare milk yield, some physico-chemical properties and the chemical composition of milk from 23 indigenous Malawi goats and 10 Malawi local × Saanen crosses was carried out from January to March 2000. The results showed that the average milk yield from the crosses (102.0 ± 11.21 kg) was higher (P < 0.01) than that from the indigenous goats (37.1 ± 4.79 kg). However, the pH and specific gravity of both milk samples did not differ significantly from each other. The latter was attributed to the fat and total solids contents, which did not differ significantly in the two milk samples. Although the crude protein content was not significantly different, lactose and minerals, namely calcium, sodium, magnesium, potassium and chloride, were higher (P < 0.01) in milk from the crosses than in milk from the indigenous goat. The results have shown that the levels of nutrients in goat milk are high, and this is indicative of its potential to improve the diets of rural Malawians. Also, as smallholder farmers sell raw unheated milk to the processing plants, such milk should not be kept for> 33 h in the cool dry season and for not> 20 h in the hot dry season. Farmers can also adopt a charcoal cooler to save the milk for an even longer time than they can at room temperature. In this case, the raw milk can only be stored for not> 20 h in the cool dry season and not> 16 h in the hot dry season. [source] The effects of starter culture on chemical composition, microbiological and sensory characteristics of Turkish Ka,ar Cheese during ripeningINTERNATIONAL JOURNAL OF DAIRY TECHNOLOGY, Issue 4 2007DURMU Ka,ar cheese samples were produced from raw milk and starter culture-added pasteurized milk. Chemical, microbiological and organoleptic properties of ka,ar cheeses were analysed at certain times during the ripening periods (on the 1st, 7th, 15th, 30th, 60th, 90th days). Generally, chemical parameters were not affected by starter culture. The pH, ripening index, water-soluble nitrogen and non-protein nitrogen did not show significant differences between the cheese samples. The addition of starter affected the microbiological quality of the cheeses. Starter culture-added ka,ar cheeses contained low levels of total aerobic mesophilic bacteria, moulds and yeasts, and coliforms, and achieved higher organoleptic scores than those of cheeses made from raw milk. The starter cultures contributed to acidity and microbial quality of the cheese. [source] Ripening of traditional Örgü cheese manufactured with raw or pasteurized milk: Composition and biochemical propertiesINTERNATIONAL JOURNAL OF DAIRY TECHNOLOGY, Issue 4 2007SERAFETTIN CELIK The changes in composition and some biochemical properties of Örgü cheeses made from raw (RMC) and pasteurized (PMC) cow milk were investigated during a 90-day ripening period. The average contents of total solids (TS), protein, water soluble nitrogen (WSN), trichloro-acetic acid soluble nitrogen (TCA-SN) and acid degree value (ADV) were lower, while salt and salt in TS were found to be statistically higher in PMC than RMC (P < 0.05). In addition, in both RMC and PMC, the TS and protein contents were decreased as compared to an increase in salt, salt in TS, WSN and TCA-SN contents, and ADV, during ripening (P < 0.05). The evaluation of WSN, TCA-SN and ADV shows that these two experimental Örgü cheese types undergo little proteolysis and lipolysis. On the other hand, acidity development was observed to be high in both before curdling and in cheese made from raw milk during ripening. [source] Mexican Queso Chihuahua: rheology of fresh cheese,INTERNATIONAL JOURNAL OF DAIRY TECHNOLOGY, Issue 1 2007DIANE L VAN HEKKEN Rheological properties of fresh Queso Chihuahua made from raw milk (RM) or pasteurized milk (PM) were characterized using texture profile, torsion and small amplitude oscillatory shear analyses. Although the rheological properties varied significantly among the different brands with overlapping ranges for the individual RM and PM cheese brands, overall the PM cheeses were harder, chewier and more cohesive but had lower viscoelastic values than the RM cheeses. Establishing the rheological properties of Mexican Queso Chihuahua increases our understanding of the quality traits of Hispanic-style cheeses and provides a foundation for maintaining the traditional texture of the cheese. [source] Queso Chihuahua: effects of seasonality of cheesemilk on rheology,INTERNATIONAL JOURNAL OF DAIRY TECHNOLOGY, Issue 1 2007MICHAEL H TUNICK Fresh semihard raw milk (RM) and pasteurized milk (PM) cheeses made by Mennonite communities in Chihuahua, Mexico were sampled in early winter, mid-spring and late summer and evaluated during storage to determine if rheological properties were affected by the season the cheese was produced. Seasonal effects were observed in the rheology of the RM cheeses, which underwent more extensive proteolysis than the PM cheeses. The rheological properties of the PM cheeses and the composition of all cheeses were consistent throughout the year. The texture of the RM cheese is affected by season, whereas the variability in texture and composition of PM cheese is minimal, allowing for the manufacture of a uniform product. [source] Investigation of the impact of simulated commercial centrifugation and microfiltration conditions on levels of Mycobacterium avium ssp. paratuberculosis in milkINTERNATIONAL JOURNAL OF DAIRY TECHNOLOGY, Issue 3 2005IRENE R GRANT The potential for physical removal of Mycobacterium avium ssp. paratuberculosis (M. paratuberculosis) from milk by centrifugation and microfiltration was investigated by simulating commercial processing conditions in the laboratory by means of a microcentrifuge and syringe filters, respectively. Results indicated that both centrifugation of preheated milk (60°C) at 7000 × g for 10 s, and microfiltration through a filter of pore size 1.2 µm, were capable of removing up to 95,99.9% of M. paratuberculosis cells from spiked whole milk and Middlebrook 7H9 broth suspensions, respectively. Centrifugation and microfiltration may therefore have potential application within the dairy industry as pretreatments to reduce M. paratuberculosis contamination of raw milk. [source] Mycobacterium avium ssp. paratuberculosis: its incidence, heat resistance and detection in milk and dairy productsINTERNATIONAL JOURNAL OF DAIRY TECHNOLOGY, Issue 1 2001Irene R Grant Mycobacterium avium ssp. paratuberculosis (MAP) causes Johne's disease in cattle and other ruminants and has been implicated as a possible cause of Crohn's disease in humans. The organism gains access to raw milk directly through excretion into the milk within the udder, and indirectly through faecal contamination during milking. MAP has been shown to survive commercial pasteurization in naturally infected milk, even at the extended holding time of 25 s. Pasteurized milk must therefore be considered a vehicle of transmission of MAP to humans. Isolation methods for MAP from milk are problematical, chiefly because of the absence of a suitable selective medium. This makes food surveillance programs and research on this topic difficult. The MAP problem can be addressed in two main ways: by devising a milk-processing strategy that ensures the death of the organism; and/or strategies at farm level to prevent access of the organism into raw milk. Much of the research to date has been devoted to determining if a problem exists and, if so, the extent of the problem. Little has been directed at possible solutions. Given the current state of information on this topic and the potential consequences for the dairy industry, research is urgently needed so that a better understanding of the risks and the efficacy of possible processing solutions can be determined. [source] smcL as a novel diagnostic marker for quantitative detection of Listeria ivanovii in biological samplesJOURNAL OF APPLIED MICROBIOLOGY, Issue 3 2010D. Rodríguez-Lázaro Abstract Aims:, To develop a novel molecular tool for the quantitative detection of the ruminant pathogen Listeria ivanovii in different biological matrices. Methods and Results:, A real-time PCR (RTi-PCR) for the quantitative and species-specific identification of L. ivanovii was designed to target the region of the smcL gene. The assay includes an internal amplification control (IAC) to avoid false-negative results. The smcL -IAC RTi-PCR assay was 100% selective and allowed the detection of as little as one genome equivalent in 45% of reactions. The quantification accuracy was excellent, as demonstrated by its high linearity (R2 > 0·9989) and PCR efficiency (E > 0·984) over a 6-log dynamic range, down to 10 genome equivalents. Finally, the applicability of this assay was evaluated with artificially contaminated biological matrices implicated in the transmission of this bacterium such as sheep raw milk, blood and amniotic fluid. The smcL -IAC RTi-PCR assay allowed the detection of as few as 50 colony forming unit numbers (CFUs) per 25 ml of raw milk, 43 CFUs per 1 ml of blood or 50 CFUs per 1 ml of amniotic fluid. Conclusions:, This method can be an adequate alternative for the identification of L. ivanovii and for complete diagnosis of animal and human listeriosis. Significance and Impact of the Study:, We present an alternative for the detection of another pathogenic member of Listeria genus, which can help to distinguish from Listeria monocytogenes and therefore facilitates the establishment of preventive and prophylactic measures in food and farm environments. [source] Inactivation of Staphylococcus aureus in raw milk cheese by combinations of high-pressure treatments and bacteriocin-producing lactic acid bacteriaJOURNAL OF APPLIED MICROBIOLOGY, Issue 2 2005J.L. Arqués Abstract Aims:, To investigate the combined effect of high-pressure treatments (HPT) and milk inoculation with bacteriocin-producing lactic acid bacteria (BP-LAB) on the survival of Staphylococcus aureus during ripening of raw milk cheese. Methods and Results:, Cheeses were manufactured from raw milk artificially contaminated with S. aureus at ca 5 log CFU ml,1, a commercial starter culture and one of seven strains of BP-LAB, added as adjuncts at 0·1%. HPT of cheeses were performed on days 2 or 50 at 300 MPa (10°C, 10 min) or 500 MPa (10°C, 5 min). On day 3, S. aureus counts were 6·46 log CFU g,1 in control cheese. Milk inoculation with different BP-LAB lowered S. aureus counts on day 3 when compared with control cheese by up to 0·46 log CFU g,1, HPT at 300 MPa on day 2 by 0·45 log CFU g,1 and HPT at 500 MPa on day 2 by 2·43 log CFU g,1. Combinations of BP-LAB with HPT at 300 and 500 MPa on day 2 lowered S. aureus counts on day 3 by up to 1·02 and 4·00 log CFU g,1 respectively. Conclusions:, The combined effect of milk inoculation with some of the BP-LAB tested and HPT of cheese on S. aureus inactivation was synergistic. Significance and Impact of the Study:, The combination of HPT at lower pressures with BP-LAB inoculation is a feasible system to improve cheese safety in case of deleterious effects on cheese quality caused by HPT at higher pressures. [source] Isolation and characterization of a protease from Pseudomonas fluorescens RO98JOURNAL OF APPLIED MICROBIOLOGY, Issue 2 2000R. Koka Pseudomonas fluorescens RO98, a raw milk isolate, was inoculated into McKellar's minimal salts medium and incubated at 25 °C for 48 h to allow production of protease. A zinc-metalloacid protease was purified from the cell-free concentrate by anion exchange and gel filtration chromatography. The purified protease was active between 15 and 55 °C, and pH 4·5 and 9·0, and was stable to pasteurization. The enzyme had pH and temperature optima for activity of 5·0 and 35 °C, respectively. It was heat stable with a D55 of 41 min and a D62·5 of 18 h. Molecular weight of the enzyme was estimated to be 52 kDa by SDS PAGE and size exclusion chromatography. Values for kM of 144·28, 18·73, 110·20 and 35·23 µmol were obtained for whole, ,-, ,- and ,-casein, with a Vmax of 8·26, 0·09, 0·42 and 0·70 µmol mg,1 min,1, respectively. The enzyme hydrolysed ,-casein preferentially when incubated with artificial casein micelles. [source] THERMAL INACTIVATION KINETICS OF ALKALINE PHOSPHATASE IN BUFFER AND MILKJOURNAL OF FOOD PROCESSING AND PRESERVATION, Issue 3 2006S. FADILO ABSTRACT A detailed kinetic study on the thermal inactivation of alkaline phosphatase (ALP) added into buffer and pasteurized milk and for ALP naturally present in raw cow's milk has been performed. Kinetic parameters (rate constant, k; decimal reduction time, D; activation energy, Ea; and z value) were evaluated based on the first-order rate model at 50,80C. The temperature sensitivity of the kinetic parameters was evaluated considering the Arrhenius-type Ea model. All kinetic behaviors were well described by the first-order model (r2 > 0.91). The D values increased with increasing temperature. Higher temperatures resulted in higher rates of enzyme inactivation as indicated by lower D values and higher k values. There are significant differences (P < 0.01) among the D values for ALP in buffer and milk at treated temperatures. The rate of enzyme inactivation was much more rapid in buffer than in pasteurized milk. The evaluated Ea values for ALP added into the buffer and pasteurized milk, and for ALP naturally present in raw milk were 97.2, 149.9 and 207.8 kJ/mol, respectively. The inactivation kinetics of ALP during heat treatment was found to be dependent on the composition of the medium, and the time and temperature of the heat treatment. [source] RHEOLOGY AND TEXTURE OF COMMERCIAL QUESO FRESCO CHEESES MADE FROM RAW AND PASTEURIZED MILKJOURNAL OF FOOD QUALITY, Issue 2010MICHAEL H. TUNICK ABSTRACT Queso Frescos made in Mexico from raw milk (RM) were compared with cheeses made in Mexico and the U.S.A. from pasteurized milk (PM) to determine textural and rheological differences. RM cheese, considered the ideal Queso Fresco, contained more moisture than PM cheeses, displayed higher cohesiveness and shear strain and exhibited lower hardness and shear stress. The U.S.-made cheeses were harder and more brittle and crumbly than the Mexican cheeses. The shear stress decreased as fat content increased in all samples, and the shear strain decreased as the pH increased in the Mexican cheeses. An understanding of the differences between the RM and PM versions should allow cheese makers to adjust manufacturing procedures so that PM Queso Fresco cheeses will meet consumer expectations. PRACTICAL APPLICATIONS Hispanic cheeses such as Queso Fresco are gaining in popularity in the U.S.A. The milk for making Queso Fresco in the U.S.A. must be pasteurized, and the resulting cheese is perceived by some consumers to be inferior in flavor and texture to the traditional variety made from raw milk. Queso Fresco samples made in Mexico from both kinds of milk and made in the U.S.A. from pasteurized milk were analyzed to see if there were differences in texture, structure, and the ability to twist and break pieces of the cheese. The cheeses made in the U.S.A. contained less moisture and were too hard, crumbly, and brittle when compared to the raw milk cheeses. The differences observed should enable U.S. companies to make Queso Fresco with properties close to those of the raw milk variety. [source] EFFECT OF MILK PASTEURIZATION ON FLAVOR PROPERTIES OF SEVEN COMMERCIALLY AVAILABLE FRENCH CHEESE TYPESJOURNAL OF SENSORY STUDIES, Issue 4 2010DELORES H. CHAMBERS ABSTRACT Previous research on matched pairs of experimental cheese showed that heat treatment of milk affected flavor properties. However, whether pasteurization has a generalized effect or whether the effect is specific to certain cheese varieties is not known. Experienced, highly trained sensory panelists developed flavor profiles for seven commercially available French cheeses (Brie, Coulommier, Camembert, Saint Nectaire, Muenster, Chèvre and Bleu) for which versions made from pasteurized or unpasteurized milk were commercially available. Raw-milk cheese had stronger odor properties. Soft cheeses with white rind (Brie, Coulommier, Camembert and Saint Nectaire) as well as Chèvre and Bleu were affected similarly by heat treatment of milk, but the sensory characteristics of Muenster cheese did not follow the pattern of other cheeses. These results suggest that many, but not all, cheese types show similar changes in sensory attributes as a result of using pasteurized rather than raw milk. PRACTICAL APPLICATIONS This study gives manufacturers and researchers information on flavor differences that exist between similar cheese types made from raw or pasteurized milk. Researchers and manufacturers can use that information in order to develop pasteurized-milk cheese that has the traditional full-flavored characteristics of its raw-milk counterpart. [source] Detection of Staphylococcus aureus and enterotoxin genotype diversity in Monte Veronese, a Protected Designation of Origin Italian cheeseLETTERS IN APPLIED MICROBIOLOGY, Issue 5 2007A. Poli Abstract Aims:, To evaluate the risk associated with the load and enterotoxigenicity of Staphylococcus aureus in Monte Veronese, a PDO (Protected Designation of Origin) cheese of the Lessinia area (Verona, Italy). Methods and Results:,Staphylococcus aureus was quantified by a conventional culture method and by a nucA targeted real-time PCR assay developed in this study. Staphylococcus aureus numbers in cheese were higher than the limit tolerated by the Italian food legislation in 78% instances, according to both detection methods. Multiplex PCR tests for 17 Staph. aureus enterotoxin (SE) genes were applied to nucleic acids extracted from curds, cheeses and Staph. aureus isolates. The SE gene diversity appeared reduced after ripening. The gene encoding SED was found most frequently in dairy samples and the enterotoxin genes ser, sed, seg and sem predominated in the isolates. Conclusions:, The occurrence of enterotoxigenic Staph. aureus strains with complex SE genotypes in this PDO cheese at numbers often exceeding the Italian tolerance threshold represents an important risk factor. Significance and Impact of the Study:, The high frequency of contamination of Monte Veronese PDO cheese and, expectedly, similar typical productions from raw milk, by enterotoxigenic Staph. aureus imposes a tighter hygienic control in the earlier manufacturing phases. [source] Inhibition of bacteriophage K proliferation on Staphylococcus aureus in raw bovine milkLETTERS IN APPLIED MICROBIOLOGY, Issue 3 2005S. O'Flaherty Abstract Aims:, To assess the ability of staphylococcal bacteriophage K to inhibit Staphylococcus aureus in raw milk. Methods and Results:, The ability of bacteriophage (phage) to replicate in milk is important in situations where phage might be used as a therapeutic for bovine mastitis. Phage K was able to replicate normally, leading to elimination of the host culture in milk, which had been previously heat-treated. When raw milk was used under identical conditions, the phages were unable to replicate. Phage adsorption assays were performed and these demonstrated that adsorption of phage was significantly reduced in the raw milk while it was restored in the heat-treated sample (86·50% compared with 99·96% adsorption respectively). When confocal microscopy with a Live/Dead Bac light staining system was employed, it was observed that in raw milk S. aureus formed clusters associated with fat globules, while in heat-treated milk, bacterial agglutination had not occurred. Conclusions:, Raw milk inhibits staphylococcal phage K proliferation. Significance and Impact of the Study:, This observation has implications for the exploitation of staphylococcal therapeutic phage in milk. [source] The evaluation of the curd forming ability of milk replacersANIMAL SCIENCE JOURNAL, Issue 1 2009Keiji OKADA ABSTRACT Inadequate milk curd formation in the abomasum of newborn calves causes malnutrition and diarrhea. In order to define the factors of inadequate curd formation, we compared the curd forming ability among 9 kinds of milk replacers, bulk milk (raw milk), and skim milk both in vitro and in vivo. When rennet was added, the raw milk and one milk replacer formed firm curds. The rest of the milk replacers and skim milk did not form any curd. When a solution of HCl was added, raw milk, three milk replacers and skim milk formed the curd at pH 4.5, but the other milk replacers did not. When HCl was added following the rennet, raw milk, one milk replacer and skim milk formed the curd. In vivo, raw milk, two milk replacers and skim milk showed good curd formation whereas the other milk replacers showed poor curd formation inside the abomasums of the calves. This study showed that most of the milk replacers sold in Japan could not form the curd with rennet. [source] Inter-laboratory comparison of radiometric culture for Mycobacterium avium subsp. paratuberculosis using raw milk from known infected herds and individual dairy cattle in VictoriaAUSTRALIAN VETERINARY JOURNAL, Issue 7 2010SE Ridge Objective To compare the results of radiometric culture conducted in three Australian laboratories for Mycobacterium avium subsp. paratuberculosis (Mptb) using bulk vat and individual animal milk samples. Procedure Milk samples were collected from 15 cows exhibiting clinical signs of Johne's disease, and subsequently confirmed as infected with Mptb, and from the bulk milk vats on 91 farms running herds known to be infected with Mptb. Each milk sample was divided into three equivalent samples and one of each of the replicates was forwarded to the three participating laboratories. The identity and nature of the samples was protected from the study collaborators. The laboratories processed the samples and undertook radiometric culture for Mptb using their standard method. Results of testing were provided to the principal investigator for collation and analysis. Results In total, 2 (2.2%) of 91 vat-milk samples and 8 (53.3%) of 15 individual cows' milk samples returned positive radiometric milk culture results. Only one sample, from a clinical case of Johne's disease, was identified as positive by more than one laboratory. There were differences in the absolute frequency with which Mptb was identified in the milk samples by the collaborating laboratories. Conclusions Mptb was cultured from a very small percentage of Australian raw bulk milk samples sourced from known infected herds. By contrast, Mptb was successfully cultured from half of the milk samples collected from clinically affected cows. There was no statistical difference between laboratories in the proportion of vat samples or individual animal milk samples in which Mptb was detected. [source] | ||||||||||||||||