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.

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.

Preliminary Incubation Count as an Index of Raw Milk Microbiological Quality During Storage

1984 ◽  
Vol 47 (3) ◽  
pp. 206-208 ◽  
Author(s):  
J. J. RYAN ◽  
R. H. GOUGH ◽  
C. H. WHITE
Keyword(s):  
Microbiological Quality ◽  
Storage Period ◽  
Raw Milk ◽  
Plate Count ◽  
Bacterial Counts ◽  
Sample Group ◽  
Psychrotrophic Bacteria ◽  
Standard Plate Count ◽  
Milk Samples ◽  
Standard Plate

During a 5-month period, 200 raw milk samples were collected from two Louisiana milk plants. Standard Plate Count (SPC), Psychrotrophic Bacteria Count (PBC), and Proteolytic Count (PC) of each sample were initially determined, then monitored daily during a 5-d storage period at 2.2°C. As hypothesized, all bacterial counts increased during the storage period. The magnitude of the increase in bacterial numbers during storage was further investigated by dividing the milk samples into bacteriologically acceptable and unacceptable groups based on SPC or Preliminary Incubation (PI) count. An SPC of 1.0 × 105/ml and PI counts of 1.0 × 105/ml, 1.5 × 105/ml, 2.3 × 105/ml, and 3.0 × 105/ml were used to repeatedly dichotomize the 200 raw milk samples into two groups. Median SPC, PBC, and PC for each acceptable and unacceptable group were then calculated. Dichotomization based on PI counts yielded acceptable sample groups having consistently lower bacterial counts during storage than did the acceptable sample group, which resulted from the dichotomization based on a SPC of 1.0 × 105/ml. The results of this study indicated that the PI count is of considerable value for raw milk quality control.

scholarly journals MICROBIOLOGICAL QUALITY OF GOAT MILK PRODUCED ON ALAGOAS STATE, BRAZIL

2019 ◽  
Vol 11 (2) ◽  
pp. 47-56
Author(s):  
Erica Guedes Celestino ◽  
Micheline Thaís Santos ◽  
Sybelle Georgia Silva ◽  
Tania Marta Carvalho dos Santos ◽  
Elizabeth Simões do Amaral Alves ◽  
...  
Keyword(s):  
Microbiological Quality ◽  
Goat Milk ◽  
Raw Milk ◽  
Most Probable Number ◽  
Probable Number ◽  
Pasteurized Milk ◽  
Total Coliforms ◽  
Specific Medium

The objective of this study was to verify the microbiological quality of raw and pasteurized goat milk and produced in Alagoas state, Brazil. Was carried out three interval collect of pasteurized and raw milk and the samples taken to the laboratory. All samples were subjected to aerobic mesophilic microorganisms counting, psychrotrophic microorganisms, determination of the most probable number (MPN) of total coliforms and thermotolerant microorganisms. For analysis, samples were plated on specific medium (Baird-Parker Agar Base himedia M043) and incubated at 37 °C for 24h. To Salmonella sp. detection was used plating the medium Salmonella Shigella agar. The presence of coliforms at 35 °C was detected in all samples as well as 45 °C except to first sample. To the pasteurized milk was found to coliforms at 35 °C and 45 °C in the second and third samples. Only in the second test was checked the presence of mesofilic bacteria. We have not found samples contaminated with microorganisms psychrotrophic, Salmonella sp. and Staphylococcus sp. According to the obtained results the quality of collected milk has unacceptable conditions of consumption compared to coliform counts, according to the parameters established by law.

scholarly journals Assessment of the Microbiological Quality and Biochemical Parameters of Traditional Hard Xinotyri Cheese Made from Raw or Pasteurized Goat Milk

Fermentation ◽  
2022 ◽  
Vol 8 (1) ◽  
pp. 20
Author(s):  
Eleni C. Pappa ◽  
Thomas G. Bontinis ◽  
John Samelis ◽  
Kyriaki Sotirakoglou
Keyword(s):  
Microbiological Quality ◽  
Goat Milk ◽  
Raw Milk ◽  
Starter Cultures ◽  
Water Soluble ◽  
Biochemical Characteristics ◽  
Pasteurized Milk ◽  
Hydrophobic Peptides ◽  
Milk Pasteurization ◽  
Total Free Amino Acids

Traditional hard Xinotyri cheese was manufactured using raw or pasteurized goat milk, without starter cultures, and the changes in microbiological and biochemical characteristics were studied during ripening and storage. Mesophilic lactic acid bacteria (LAB) predominated (>8.5 log CFU/g) in freshly fermented Xinotyri cheeses (pH 4.5–4.6), regardless of milk pasteurization. Enterobacteria, pseudomonads and staphylococci were suppressed below 6 and 4–5 log CFU/g in fresh cheeses from raw and pasteurized milk, respectively. Salmonella and Listeria spp. were absent in 25 g cheese samples. Coagulase-positive staphylococci exceeded the 5-log safety threshold in fresh raw milk cheeses, which also had 10-fold higher levels of enterococci than pasteurized milk cheeses. Non-LAB groups declined <100 CFU/g, whereas yeasts increased to 5–6 log CFU/g in both cheeses during ripening. Milk pasteurization affected the protein, fat, ash, moisture, nitrogen fractions, total free fatty acids and total free amino acids content of cheeses. Primary proteolysis, detectable by urea-PAGE, was more intense in raw milk cheeses than in pasteurized milk cheeses. However, the hydrophilic and hydrophobic peptides and their ratio in the water-soluble fraction were similar in both cheeses. Cheeses discriminated clearly according to the milk kind (raw, pasteurized) and the stage of ripening, based on the examined biochemical characteristics.

scholarly journals Effect of HTST Thermal Treatments on End-Use Quality Characteristics of Goat Milk

2019 ◽  
Vol 2019 ◽  
pp. 1-9 ◽  
Author(s):  
B. D. Rohitha Prasantha ◽  
K. M. S. Wimalasiri
Keyword(s):  
Protein Denaturation ◽  
Goat Milk ◽  
Storage Period ◽  
Raw Milk ◽  
Heat Treatments ◽  
Thermal Treatments ◽  
Nonprotein Nitrogen ◽  
Pasteurized Milk ◽  
Milk Samples ◽  
End Use

Goat milk samples were pasteurized at high-temperature (72°C, 75°C, and 81°C) and in short-time (15 s and 25 s) combinations. Physical, chemical and microbial qualities of the pasteurized milk samples were evaluated 0, 2, 3, and 4 weeks of storage at 4°C. Despite the different thermal treatments, specific-gravity and viscosity were comparatively stable immediately after pasteurization (IAP). The viscosity of pasteurized milk at 81°C showed significant increase (P<0.05) from 1.58 ± 0.18 to 2.30 ± 0.15 mPa s during four weeks of storage. Relative lightness “L” value decreased by about 10% during the storage period of 81°C pasteurization samples. Acidity increased with heat treatment irrespective of holding time, but in 81°C pasteurized sample higher acidity was developed at end of the storage. Fat oxidation 2-3 times higher at 81°C than 72°C pasteurized samples. Total protein (TP%) and nonprotein nitrogen contents were stable IAP but TP reduced significantly (P<0.05) at two weeks storage. The whey protein denaturation increased with pasteurization treatments and storage time. Antioxidant activity of raw goat milk was 34.8 ± 5.01 μmol l−1 and was decreased by 20–43% IAP compared to raw milk samples, but gradually increased during storage. IAP, mesophilic counts were in the range of 980–110 cfu ml−1 (72°C/15–81°C/25 s) and increased from 2236 to 680 cfu ml−1 samples stored at 4 weeks. Results showed that best quality stability of pasteurized goat milk achieved by heat treatments between 72°C/25 s and 75°C/25 s heat treatments up to 3 weeks of storage under 4°C.

scholarly journals Microbiological Quality Assessment and Identification of Antibiotic Resistant Bacteria at Different Stages of the Milk Supply Chain in Dhaka City of Bangladesh

2021 ◽  
pp. 67-76
Author(s):  
Abira Nowar ◽  
Ila Ismail ◽  
Raisa Binte Iqbal ◽  
Sharmin Rumi Alim
Keyword(s):  
Supply Chain ◽  
Microbiological Quality ◽  
Raw Milk ◽  
Resistant Bacteria ◽  
Microbiological Analysis ◽  
Milk Supply ◽  
Pasteurized Milk ◽  
Milk Samples ◽  
Processing Plants ◽  
Virulent Gene

Aims: Milk works as an excellent medium for bacterial growth and can turn into a fatal source of food borne diseases when consumed without pasteurization. This study was carried out to examine the microbiological quality of milk from three different points of milk supply chain to investigate whether the dairy stakeholders are maintaining the consumer safety or not. Study Design: A cross sectional study Place and Duration: The study took place at the Food Microbiology lab of Institute of Nutrition and Food Science, University of Dhaka from November 2019 to February 2020. Methodology: A total of 60 samples were studied including raw milk from collection centers, unpackaged pasteurized milk from processing plants and packaged pasteurized milks from retail shops. After carrying out the microbiological analysis the samples were examined for determining the total bacterial count (TBC) and total coliform count (TCC). Antibiotic susceptibility test was done using disk diffusion assay and detection of virulent gene in Salmonella spp. was done by Polymerase Chain Reaction (PCR) using specific invA primer. Results: The results revealed that all raw milk samples were substandard in terms of TBC and TCC and pasteurized milks from processing plants maintained the standard quality. Importantly, packaged pasteurized milk samples from retail shops had high TBC (>4.0× 104 CFU/mL) and TCC (1.2×103 CFU/mL) containing Pseudomonas, Micrococcus, Streptococcus, Salmonella, Proteus, Staphylococcus, Bacillus and E. coli. Bacteria like Salmonella (75%), Proteus (62.5%) and Vibrio (62.5%) possessed high Multiple Antibiotic Resistance (MAR) index and showed resistance towards antibiotics namely Ampicillin, Amoxicillin, Erythromycin and Colistin. Through further molecular analysis we detected invA virulent gene one of the Salmonella isolates which was collected from the pasteurized milk samples of the retail shops. Conclusion: High bacterial load in raw milk and packaged pasteurized milk indicate that the milk we consume is substandard in microbiological quality. Precautionary measurements and careful processing of milk may reduce the prevalence of microbiological contamination in the milk supply chain.

scholarly journals Microbiological quality analysis of raw, pasteurized, UHT milk samples collected from different locations in Bangladesh

2015 ◽  
Vol 4 (1) ◽  
pp. 5-8 ◽  
Author(s):  
Sourav Kumar Banik ◽  
Kamal Kanta Das ◽  
Md Aftab Uddin
Keyword(s):  
Microbiological Quality ◽  
Bacterial Count ◽  
Raw Milk ◽  
Total Coliform ◽  
Point Of View ◽  
Quality Analysis ◽  
Expiry Date ◽  
Pasteurized Milk ◽  
Milk Samples

Present study attempted to determine the microbiological quality of raw, pasteurized and UHT (Ultra High Temperature-processed) milk samples collected from different locations in Bangladesh. A total of 46 samples were studied including 22 raw milk samples from the local dairy markets and 24 different brands of pasteurized and ultrahigh temperature (UHT) treated milk manufactured in different beverage industries. The samples were examined for determining the total viable bacterial count (TVBC) and total coliform count (TCC). Results revealed that the raw milk samples were substandard in terms of TVBC and TCC. The range of TVBC and TCC in raw milk samples was 5.2×108 to 1.3×107 cfu/ml and 4.2×104 to 1.0×104 cfu/ml, respectively. On the contrary, the quality of pasteurized and UHT-treated milks was excellent. The TVBC range in pasteurized milk samples was from 1.8×103 to 1.1×102 cfu/ml, slightly lower than that recommended by the Bangladesh Standards and Testing Institution (BSTI). Interestingly sample numbers P-6, P-10 and P-12 of pasteurized milk samples had no growth at all both in terms of TVBC and TCC and none of the UHT processed milk contained any bacteria. So from the consumer point of view, both types of processed milk can be considered safe for consumption within the mentioned expiry date. DOI: http://dx.doi.org/10.3329/sjm.v4i1.22753 Stamford Journal of Microbiology, Vol.4(1) 2014: 5-8

Comparison of Methods for Isolation of Listeria from Raw Milk

1991 ◽  
Vol 54 (8) ◽  
pp. 602-606 ◽  
Author(s):  
A. M. LUND ◽  
E. A. ZOTTOLA ◽  
D. J. PUSCH
Keyword(s):  
Raw Milk ◽  
Enrichment Broth ◽  
Cell Counts ◽  
Listeria Ivanovii ◽  
Time Period ◽  
Secondary Enrichment ◽  
Standard Plate ◽  
Plate Counts ◽  
Low Incidence ◽  
Listeria Welshimeri

Methods used to isolate Listeria spp. from raw milk were compared during a 13-month period (April 1989–April 1990). Raw milk was obtained bimonthly from 12 dairy farms during this time period. Three enrichments were compared: Listeria enrichment broth (LEB); University of Vermont medium (UVM), followed by a secondary enrichment with Fraser broth; and LPALCAMY. Four selective plating media, including Listeria selective agar-Oxford formulation; Modified McBride Listeria agar (MMLA); Lithium chloride-phenylethanol-moxalactam (LPM) agar; and L-PALCAM agar, were compared. L-PALCAMY enrichment broth enhanced isolation of L. monocytogenes and other Listeria spp. The greatest numbers of positive Listeria samples were obtained on Oxford and PALCAM agars, while the poorest isolation was obtained using the combination of LEB with MMLA. L. monocytogenes was found to be present in 3.0% (9/300) of the samples analyzed. The incidence of Listeria spp. was 28.0%; Listeria innocua, 26.7%; and Listeria welshimeri, 1.7%. Listeria ivanovii was not isolated. The incidence of Listeria was highest during the warmer months of April–July, while the lowest incidences occurred in December and February. Somatic cell counts (SCC) and standard plate counts (SPC) were determined by the cooperative that supplied the raw milk. In general, a producer's milk with high SPC corresponded to a high incidence of Listeria spp., while low SPC corresponded to a low incidence. A particular producer's milk with the highest incidence of Listeria spp. also had the highest SCC.

Effect of Phage on Survival of Salmonella Enteritidis during Manufacture and Storage of Cheddar Cheese Made from Raw and Pasteurized Milk

2001 ◽  
Vol 64 (7) ◽  
pp. 927-933 ◽  
Author(s):  
RAJESH MODI ◽  
Y. HIRVI ◽  
A. HILL ◽  
M. W. GRIFFITHS
Keyword(s):  
Lactic Acid ◽  
Salmonella Enteritidis ◽  
Cheddar Cheese ◽  
Raw Milk ◽  
Final Concentration ◽  
Pasteurized Milk ◽  
Ph Values ◽  
Standard Procedures ◽  
Raw Milk Cheese ◽  
And Storage

The ability of Salmonella Enteritidis to survive in the presence of phage, SJ2, during manufacture, ripening, and storage of Cheddar cheese produced from raw and pasteurized milk was investigated. Raw milk and pasteurized milk were inoculated to contain 104 CFU/ml of a luminescent strain of Salmonella Enteritidis (lux) and 108 PFU/ml SJ2 phage. The milks were processed into Cheddar cheese following standard procedures. Cheese samples were examined for Salmonella Enteritidis (lux), lactic acid bacteria, molds and yeasts, coliforms, and total counts, while moisture, fat, salt, and pH values were also measured. Salmonella Enteritidis (lux) was enumerated in duplicate samples by surface plating on MacConkey novobiocin agar. Bioluminescent colonies of Salmonella Enteritidis were identified in the NightOwl molecular imager. Samples were taken over a period of 99 days. Counts of Salmonella Enteritidis (lux) decreased by 1 to 2 log cycles in raw and pasteurized milk cheeses made from milk containing phage. In cheeses made from milks to which phage was not added, there was an increase in Salmonella counts of about 1 log cycle. Lower counts of Salmonella Enteritidis (lux) were observed after 24 h in pasteurized milk cheese containing phage compared to Salmonella counts in raw milk cheese with phage. Salmonella Enteritidis (lux) survived in raw milk and pasteurized milk cheese without phage, reaching a final concentration of 103 CFU/g after 99 days of storage at 8°C. Salmonella did not survive in pasteurized milk cheese after 89 days in the presence of phage. However, Salmonella counts of approximately 50 CFU/g were observed in raw milk cheese containing phage even after 99 days of storage. In conclusion, this study demonstrates that the addition of phage may be a useful adjunct to reduce the ability of Salmonella to survive in Cheddar cheese made from both raw and pasteurized milk.

scholarly journals Biochemical characteristics of reduced-fat cheese made from high-heat treated goat’s milk supplemented with Penicillium candidum

2019 ◽  
Vol 70 (3) ◽  
pp. 1669
Author(s):  
S. KAMINARIES ◽  
A. SCORDOBEKI ◽  
E. ZOIDOU ◽  
G. MOATSOU
Keyword(s):  
Goat Milk ◽  
Raw Milk ◽  
High Heat ◽  
Water Soluble ◽  
Soluble Nitrogen ◽  
Pasteurized Milk ◽  
Reduced Fat ◽  
Goat Cheese ◽  
Protected Designation Of Origin ◽  
Penicillium Candidum

Novel reduced-fat goat-cheese (R) was produced from high-pasteurized milk using Penicillium candidum as an adjunct. A full-fat goat-cheese (F) from pasteurized milk without mold addition was produced for comparison reasons. Physicochemical analyses of the two cheeses were performed through the 14-d period of ripening. The effect of P.candidum on proteolysis of goat-cheese caseins and the production of hydrophilic and hydrophobic peptides during cheese ripening were investigated. To our knowledge, similar results for reduced-fat, mold-ripened, goat-milk cheeses have not been previously reported before. R-cheese exhibited a higher organoleptic score and developed properties similar to Kopanisti, which is a Protected Designation of Origin Greek soft cheese with specific intense flavour manufactured from raw milk without the use of starters. Moreover, R-cheese had significantly higher moisture, protein in dry matter and water soluble nitrogen contents than F-cheese and was less adhesive. The high-pasteurization improved the texture and cheese yield, while the use of P. candidum as an adjunct improved the flavour, increased and accelerated proteolysis in R-cheese. According to the results, the technology for R-cheese employed in the present study can be easily adopted and could be used to produce a reduced-fat goat-cheese.

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