Detection of Chromobacterium Violaceum in Pasteurized Milk Samples From an Organized Dairy Plant in Thrissur, Kerala

2011 ◽  
Vol 4 (3) ◽  
pp. 420-421 ◽  
Author(s):  
Ambily R Ambily R ◽  
◽  
Beena A.K. Beena A.K. ◽  
Krishna, S. V. Krishna, S. V.
Keyword(s):  
Chromobacterium Violaceum ◽  
Pasteurized Milk ◽  
Milk Samples ◽  
Dairy Plant

Prevalence of Staphylococcus aureus in Raw and Pasteurized Milk Used for Commercial Manufacturing of Brazilian Minas Cheese

1981 ◽  
Vol 44 (3) ◽  
pp. 172-176 ◽  
Author(s):  
EDSON CLEMENTE dos SANTOS ◽  
CONSTANTIN GENIGEORGIS ◽  
THOMAS B. FARVER
Keyword(s):  
Agar Plate ◽  
Raw Milk ◽  
Plate Count ◽  
Pasteurized Milk ◽  
Milk Samples ◽  
Plate Count Agar ◽  
Three Samples ◽  
Dairy Plant ◽  
Cap Method ◽  
Ml Detection

Raw and pasteurized milks used for cheesemaking were surveyed in a dairy plant, Juiz de Fora, MG, Brazil from 1978 to 1979. Raw milk samples were collected from 78 of 127 milk producers supplying 12,000–15,000 liters of milk daily to the plant. The TPC ranged from (log10) 4 CFU/ml to 7.17 CFU/ml with a (log10) mean of 5.59 CFU/ml. S. aureus cells were present in 46.9% of the samples. Mean number of S. aureus was (log10) 4.69 ± 0.54 CFU/ml; the highest number was (log10) 5.99 CFU/ml. Counts based on isolation on TPEY medium and confirmation on coagulase agar plate (CAP) did not differ significantly (P >0.05) from counts based on isolation on Plate Count Agar/DNA agar and confirmation of nuclease-positive colonies on CAP. Fifty bulk pasteurized milk samples were collected from five milk collection systems. TPC had a mean (log10) of 4.02 ± 0.62 CFU/ml with the highest count being (log10) 5.6 CFU/ml. The pH of the milk ranged from 6.55 to 6.89. Type of collection system did not affect the pH of the milk or the TPC (P >0.05). Three samples contained S. aureus at levels of (log10) 3, 2.3 and 4.43 CFU/ml. Detection of S. aureus was based on methods used for raw milk plus use of Baird-Parker/CAP method.

Characterization of Serratia species and qualitative detection of Serratia marcescens in raw and pasteurized milk by an analytical method based on polymerase chain reaction

2021 ◽  
Vol 67 (2) ◽  
pp. 3453-3464
Author(s):  
Evelin Korcz ◽  
László Varga ◽  
Zoltán Kerényi
Keyword(s):  
Serratia Marcescens ◽  
Bacterial Species ◽  
Relevant Literature ◽  
Inhibitory Effect ◽  
Test Methods ◽  
In Vitro Assays ◽  
Pasteurized Milk ◽  
Milk Samples ◽  
Microbiological Methods

Serratia species are opportunistic pathogenic microorganisms primarily known as nosocomial infectious agents, which can also cause food quality problems. The appearance of the extracellular pigment-producing Serratia marcescens in cow’s milk causes its red discoloration, posing a challenge to the dairy industry and food certification laboratories. The detection of the bacterium by conventional procedures based on microbiological methods is time-consuming and labor-intensive, and in many cases does not lead to satisfactory results due to the competitive inhibitory effect of the accompanying microflora. Following the analysis of the relevant literature, the published endpoint PCR methods and the primers used for the detection of S. marcescens were evaluated in in silico and in vitro assays, and then the procedure was tested on farm milk samples. Using the method, a total of 60 raw and pasteurized milk samples were analyzed, more than half of which (i.e., 32) were identified as S. marcescens positive. The significance of our work is mainly represented by the application of the published test methods in food industry practice. Our results highlight to the importance of detecting this bacterial species.

Heat-Resistant Psychrotrophic Bacteria Isolated from Pasteurized Milk1

1977 ◽  
Vol 40 (2) ◽  
pp. 101-108 ◽  
Author(s):  
C. J. WASHAM ◽  
H. C. OLSON ◽  
E. R. VEDAMUTHU
Keyword(s):  
Thermal Resistance ◽  
Shelf Life ◽  
Detailed Examination ◽  
Genus Bacillus ◽  
Pasteurized Milk ◽  
Psychrotrophic Bacteria ◽  
Milk Samples ◽  
Heat Resistant ◽  
Different Types

Psychrotrophic bacteria were isolated from 227 pasteurized milk samples which had a shelf life in excess of 20 days at 7.2 C. Of 700 cultures isolated, 135 were resistant to heating at 72 C for 16 sec and were able to re-establish growth at 7.2 C. Thirty-five cultures, representing 15 different types were subjected to detailed examination to determine their actions on refrigerated milk, growth temperatures, thermal resistance at various temperatures, and their identities. The spore-forming genus Bacillus occured most frequently. The non-sporing types were assigned to the genera Arthrobacter, Microbacterium, Streptococcus, and Corynebacterium.

Low Incidence of Foodborne Pathogens of Concern in Raw Milk Utilized for Farmstead Cheese Production

2008 ◽  
Vol 71 (8) ◽  
pp. 1580-1589 ◽  
Author(s):  
DENNIS J. D'AMICO ◽  
ERROL GROVES ◽  
CATHERINE W. DONNELLY
Keyword(s):  
Foodborne Pathogens ◽  
Microbiological Quality ◽  
Goat Milk ◽  
Raw Milk ◽  
Pasteurized Milk ◽  
Milk Samples ◽  
Cell Counts ◽  
Standard Plate ◽  
Low Incidence ◽  
Raw Milk Cheese

Overall milk quality and prevalence of four target pathogens in raw milk destined for farmstead cheesemaking was examined. Raw milk samples were collected weekly from June to September 2006 from 11 farmstead cheese operations manufacturing raw milk cheese from cow's, goat's, and sheep's milk. Samples were screened for Listeria monocytogenes, Staphylococcus aureus, Salmonella, and Escherichia coli O157:H7 both quantitatively (direct plating) and qualitatively (PCR). Overall, 96.8% of samples had standard plate counts of <100,000 CFU/ml, 42.7% of which were <1,000 CFU/ml. Although no federal standards exist for coliforms in raw milk, 61% of samples tested conformed to pasteurized milk standards under the U.S. Pasteurized Milk Ordinance (PMO) at <10 CFU/ml. All cow and sheep milk samples and 93.8% of goat milk samples were within the limits dictated by the PMO for somatic cell counts. Of the 11 farms, 8 (73%) produced samples that were positive for S. aureus, which was detected in 34.6% (46 of 133) of milk samples. L. monocytogenes was isolated from three milk samples (2.3%), two of which were from the same farm. E. coli O157:H7 was recovered from one sample of goat's milk for an overall incidence of 0.75%. Salmonella was not recovered from any of the 133 samples. The findings of this study suggest that most raw milk intended for farmstead cheesemaking is of high microbiological quality with a low incidence of pathogens. These data will help inform risk assessments associated with the microbiological safety of farmstead cheeses, particularly those manufactured from raw milk.

Detection of Bacillus cereus Diarrheal Enterotoxin in Raw and Pasteurized Milk

1997 ◽  
Vol 60 (11) ◽  
pp. 1391-1394 ◽  
Author(s):  
JOSEPH A. ODUMERU ◽  
ANN K. TONER ◽  
C. ANNE MUCKLE ◽  
MANSEL W. GRIFFITHS ◽  
JOHN A. LYNCH
Keyword(s):  
Bacillus Cereus ◽  
Raw Milk ◽  
Latex Agglutination ◽  
Moderate Temperature ◽  
Quality Analysis ◽  
Pasteurized Milk ◽  
Milk Samples ◽  
Enterotoxin B ◽  
Culture Supernatants

Raw and pasteurized milk samples submitted for routine quality analysis were screened for the presence of Bacillus cereus diarrheal enterotoxin (BDE) using the TECRA BDE Visual Immunoassay (VIA) kit. BDE was not detected in 298 raw milk samples tested by the TECRA VIA. B. cereus was isolated from 2 of 298 (0.7%) raw milk samples cultured. Culture supernatants from these isolates were positive for BDE in the TECRA VIA but negative in the Reverse Passive Latex Agglutination (RPLA) test for BDE. Forty-three of 112 (38.4%) pasteurized milk samples incubated at 10°C until their expiry dates were positive for BDE by the TECRA VIA. The same number of samples incubated at 4°C had no detectable levels of enterotoxin. B. cereus in the range of 103 to 106 CFU/ml was isolated from all BDE-positive pasteurized milk samples. BDE was detected in the culture supernatants of all the 43 isolates by TECRA VIA and in 30 of these isolates by RPLA. These results demonstrate that moderate temperature abuse of pasteurized milk may allow the growth of B. cereus and BDE production.

Evaluation of an 18°C/45-Hour Plate Count Technique for the Enumeration of Psychrotrophic Bacteria in Raw and Pasteurized Milk

1983 ◽  
Vol 46 (6) ◽  
pp. 528-529 ◽  
Author(s):  
HARRY K. OEHLRICH ◽  
ROBIN C. MCKELLAR
Keyword(s):  
Plate Count ◽  
Reliable Estimate ◽  
Additional Test ◽  
Bacterial Counts ◽  
Pasteurized Milk ◽  
Psychrotrophic Bacteria ◽  
Milk Samples

Bacterial counts were done at 7°C for 10 d and at 18°C for 45 h on 93 samples of raw and 185 samples of pasteurized milk. As an additional test, catalase-positive microorganisms were enumerated at 18°C/45 h. Close correlations were obtained between the numbers of microorganisms following 18°C/45-h and 7°C/10-d incubations in raw (r2=0.866) and pasteurized (r2=0.936) milk samples. Similar correlations (r2=0.860 and 0.946) were noted for the 18°C/45-h-catalase and the 7°C/10-d methods for raw and pasteurized milk, respectively. Results suggest that incubation at 18°C for 45 h provides a reliable estimate of the numbers of psychrotrophs in raw and pasteurized milk and that the use of catalase does not improve sensitivity of the test significantly.

scholarly journals Influence of the microbiological quality of raw milk on the shelf life of pasteurized milk

2019 ◽  
Vol 40 (4) ◽  
pp. 1469
Author(s):  
José Carlos Ribeiro Júnior ◽  
Aline Marangon de Oliveira ◽  
Fernando Godoi Silva ◽  
Lorena Natalino Haber Garcia ◽  
Cátia Maria de Oliveira Lobo ◽  
...  
Keyword(s):  
Shelf Life ◽  
Microbiological Quality ◽  
Raw Milk ◽  
Poor Quality ◽  
Pasteurized Milk ◽  
Microbial Counts ◽  
Legal Standards ◽  
Milk Samples ◽  
Brazilian Standard

The dairy industry strives to produce high quality products with high nutritional value as well as to meet the legal standards for longer shelf life. However, these goals are made unfeasible by the poor quality of raw milk produced in some regions of Brazil. Others Brazilian dairy regions, however, already succeed in producing milk with low microbial counts, such as the municipality of Castro, Paraná state, designated as the ‘Brazilian dairy capital’. In order to evaluate the effect of raw milk quality on microbial counts during the shelf life of pasteurized milk, samples were collected from two dairy regions of Paraná: the northern and Castro region, characterized by milk production with high and low microbiological counts, respectively. Samples were experimentally pasteurized and the total microorganism counts were analyzed for 18 days at 7°C, using the Brazilian standard microbiological count limit for pasteurized milk (8 x 104 CFU/mL) as the end of the shelf life. Low microbiological counts in raw milk (Castro) resulted in significantly lower counts shortly after pasteurization and over the entire shelf life, meeting the pasteurized milk standard for 18 days. The temporal evolution in the counts over 18 days for the milks of high and low microbiological count was similar; however, the disparity between the absolute counts between the regions was significant (p < 0.05). Of the milk samples from northern Paraná, four (44.4%) already had counts higher than that of the legislative limit for pasteurized milk immediately after pasteurization. The others (five) reached the maximum microbiological count limit for pasteurized milk on the 6th day after pasteurization. In contrast, the milk from the Castro region remained below the limit throughout the analysis period. Thus, it can be stated that the microbiological quality of raw milk is directly related to the initial count of microorganisms after pasteurization, and that pasteurized milk produced from raw milk with low microbiological counts complies with the Brazilian legislation for 18 days following thermal processing.

Involvement of a pasteurizer in the contamination of milk by Bacillus cereus in a commercial dairy plant

2000 ◽  
Vol 67 (3) ◽  
pp. 455-460 ◽  
Author(s):  
BIRGITTA SVENSSON ◽  
ÅSA ENEROTH ◽  
JOHANNE BRENDEHAUG ◽  
GÖRAN MOLIN ◽  
ANDERS CHRISTIANSSON
Keyword(s):  
Bacillus Cereus ◽  
Raw Milk ◽  
Pasteurized Milk ◽  
Rapd Pcr ◽  
Random Amplification ◽  
Dairy Plant ◽  
Heat Activation ◽  
Contamination Routes ◽  
Microbiological Analyses

Bacillus cereus is a common contaminant in raw milk. The spores survive pasteurization and psychrotrophic strains of B. cereus often limit the keeping quality of pasteurized milk stored at > 6 °C (Griffiths, 1992). High numbers of B. cereus in pasteurized milk are most frequent when the cows are grazing (Slaghuis et al. 1997), mainly owing to increased levels of spores in raw milk resulting from teat contamination by soil (Christiansson et al. 1999). However, high numbers can also be found in pasteurized milk while the cows are housed indoors, and this is probably caused by additional contamination at the dairy plant (te Giffel et al. 1996; Larsen & Jørgensen, 1997; Lin et al. 1998). There is little information available about the sites of recontamination in the dairy. The use of typing techniques capable of discrimination below the species level, such as fatty acid profiles and random amplification of polymorphic DNA–polymerase chain reaction (RAPD–PCR), could be helpful in demonstrating contamination routes (Lin et al. 1998; Nilsson et al. 1998).Spores of B. cereus are very hydrophobic and readily adhere to surfaces of steel, glass and rubber (Rönner et al. 1990), and short cleaning-in-place programmes do not always eliminate all the spores (Rönner & Husmark, 1992). Spores adhering to surfaces are more difficult to eliminate by disinfectants than spores in solution (te Giffel et al. 1995). Many B. cereus spores germinate rapidly in milk upon heat activation and, if allowed to propagate undisturbed on surfaces, may form biofilms that are extremely difficult to eliminate (Mosteller & Bishop, 1993; Wirtanen et al. 1996; Kumar & Anand, 1998).This paper describes how we demonstrated the involvement of a pasteurizer in the contamination of pasteurized milk by B. cereus in a commercial dairy plant using a combination of classic microbiological analyses and typing of strains by RAPD–PCR.

Occurrence of aflatoxin M1 in commercial pasteurized milk samples in Sari, Mazandaran province, Iran

2016 ◽  
Vol 32 (2) ◽  
pp. 85-87 ◽  
Author(s):  
Hamidreza Mohammadi ◽  
Mohammad Shokrzadeh ◽  
Zahra Aliabadi ◽  
Bamdad Riahi-Zanjani
Keyword(s):  
Aflatoxin M1 ◽  
Mazandaran Province ◽  
Pasteurized Milk ◽  
Milk Samples

Molecular Analysis of Spoilage-Related Bacteria in Pasteurized Milk during Refrigeration by PCR and Denaturing Gradient Gel Electrophoresis

2009 ◽  
Vol 72 (3) ◽  
pp. 572-577 ◽  
Author(s):  
HONGFEI HE ◽  
JIN DONG ◽  
CHIN NYEAN LEE ◽  
YONG LI
Keyword(s):  
Shelf Life ◽  
Gel Electrophoresis ◽  
Denaturing Gradient Gel Electrophoresis ◽  
Plate Count ◽  
Pasteurized Milk ◽  
Milk Samples ◽  
Gradient Gel Electrophoresis ◽  
Aerobic Plate Count ◽  
Species Specific

Bacterial diversity in fluid milk products has been extensively studied in order to improve milk quality. Here, we illustrate the utility of viable counts and PCR–denaturing gradient gel electrophoresis (DGGE) for monitoring the microbial spoilage of pasteurized milk during shelf life. Five pasteurized milk samples stored at 4°C were examined at 10 and 5 days before expiration and on the expiration day. With bacterial DNA extracted directly from the samples, PCR-DGGE analysis indicated that Pseudomonas became dominant in four samples. Meanwhile, the aerobic plate count of these four samples exceeded the regulatory limit of 20,000 CFU/ml at 5 days before expiration, and the rapid psychrotrophic count markedly surpassed the aerobic plate count on the expiration day. Streptococcus and Buttiauxella spp. were detected in several samples. Sequence analysis of DGGE fragments revealed high diversity among Pseudomonas spp. in the milk samples. P. putida and P. migulae grew to high numbers during refrigerated storage. Further identification of Pseudomonas at the species level was facilitated by PCR and multiplex PCR using species-specific primers; consequently, P. fluorescens and P. fragi were observed. These results highlight an important role of Pseudomonas in the shelf life of pasteurized milk.

Sign in / Sign up

Export Citation Format

Share Document