scholarly journals Influence of storage temperature on the population of microorganisms in raw sheep milk and its physical-chemical profile

2020 ◽  
Vol 9 (12) ◽  
pp. e27691210796
Author(s):  
Samera Rafaela Bruzaroski ◽  
Raquel Pinheiro de Souza ◽  
Pamela da Silva Pasquim ◽  
Rafael Fagnani ◽  
Elsa Helena Walter de Santana
Keyword(s):  
Storage Time ◽  
Storage Temperature ◽  
Titratable Acidity ◽  
Raw Milk ◽  
Plate Count ◽  
Chemical Profile ◽  
Pseudomonas Spp ◽  
Psychrotrophic Bacteria ◽  
Sheep Milk ◽  
Physical Chemical

The aim of the present study was to evaluate the physical-chemical profile of raw sheep milk and the influence of storage temperature on the population of microorganisms. Sheep milk samples were collected from the milk cans (500 mL/sample) and were evaluated the physical-chemical composition: fat, protein, lactose, ash content, total dry matter (TDM), cryoscopy index (°H), titratable acidity, and somatic cell count (SCC). After the samples were stored at 4°C and 9°C (72 h) and the titratable acidity, the population of the deteriorating microorganisms and quality indicators were determined. PetrifilmTM (3M do Brasil Ltda) were used for the mesophilic aerobic count (37°C/48 h), total coliforms (37°C/24 h), Escherichia coli (37°C/48 h), and enterobacteria (37°C/24 h). For psychrotrophic bacteria, was used Plate Count Agar (7ºC/10 days) and for Pseudomonas spp., CFC-supplemented Pseudomonas agar base (25ºC/48 h). Average values for raw milk were 6.28% fat, 83.46% moisture, 16.52% TDM, 0.92% ash, 5.30% protein, 4.43% lactose, a cryoscopy index of -0.575°H, and SCC of 3.38 x 106 cells/mL. Milk acidity values were higher (0.24 g lactic acid/100 ml) with 72 hours of storage. The higher the temperature and/or storage time, the higher the counts of psychrotrophic, Pseudomonas spp., and enterobacteria, for mesophilic aerobic only the storage time. Refrigeration at 4ºC and a reduction of storage time are important to control the microorganism’s population that compromise the quality, shelf life, and food safety of sheep milk and dairy products.

scholarly journals Incidence of psychrotrophic lipolytic bacteria in cow’s raw milk

2009 ◽  
Vol 54 (No. 2) ◽  
pp. 65-73 ◽  
Author(s):  
R. Cempírková ◽  
M. Mikulová
Keyword(s):  
Storage Time ◽  
Storage Temperature ◽  
Raw Milk ◽  
Culture Methods ◽  
Mean Values ◽  
Psychrotrophic Bacteria ◽  
Milk Samples ◽  
Limit Value ◽  
Significant Difference ◽  
Medium Level

The contamination of bulk samples of cow’s raw milk (<I>n</I> = 491) by psychrotrophic lipolytic bacteria (PLiBC), total count of psychrotrophic bacteria (PBC) and mesophilic bacteria (TBC) was monitored for two years on eight dairy farms and the correlations among these groups of bacteria were analysed. An increase in TBC, PBC and PLiBC and in the values of free fatty acids (FFA) was tested experimentally in three milk samples in relation to time (analyses were done in 24-hour intervals until 96 hours) and storage temperature of milk samples (4; 6.5 and 10°C). Bacterial contamination of milk was determined by culture methods in accordance with IDF standards, the values of FFA were determined by an extraction-titration method. These mean values were determined in the set of samples (<I>n</I> = 491): PLiBC 659 CFU/ml, PBC 2 932 CFU/ml and TBC 18 932 CFU/ml. A high correlation was proved between values of PBC and PLiBC (<I>r</I> = 0.87; <I>P</I> < 0.001) while the correlation between TBC and PBC (<I>r</I> = 0.65; <I>P</I> < 0.001) and between PLiBC and TBC (<I>r</I> = 0.59; <I>P</I> < 0.001) was on a medium level. The proportional index <I>p<sub>I</sub></I> for PLiBC/PBC was 0.20, for PLiBC/TBC 0.03 and for PBC/TBC 0.16. In seasonal dynamics a statistically significant difference (<I>P</I> < 0.001; <I>P</I> < 0.05) between the increased values of TBC in the summer season was proved compared to the winter and spring season. The differences in the seasonal variation of PBC and PLiBC values were not significant. Experimental investigation of an increase in the values of tested parameters showed that at temperatures of milk sample storage 4 and 6.5°C TBC did not exceed the permissible hygienic value (100 000 CFU/ml) even after 96 hours while at 10°C it amounted to 90 000 CFU/ml after 48 hours and the limit for TBC was exceeded several times after 96 hours. PBC, which is not inhibited by cold storage to such a large extent, did not exceed the hygienic limit value for PBC (50 000 CFU/ml) even after 96 hours when milk samples were stored at 4°C, but at 6.5°C after 72 hours and at 10°C already after 48 hours the values 6 and 20 times higher, respectively, than the hygienic limit were recorded. A similar trend was observed in PLiBC, which exceeded the hazardous limit (43 000 CFU/ml) at 6.5°C after 96 hours and at 10°C already after 48 hours whereas at 4°C the limit value was not exceeded even after 96 hours. The content of FFA also increased in relation to the storage time and temperature of milk samples but in comparison with the increase in the tested groups of microorganisms the increase in FFA showed a higher correlation with storage time compared to storage temperature. A medium correlation was calculated between PLiBC and/or PBC and FFA content (<I>r</I> = 0.52; <I>r</I> = 0.57; <I>P</I> < 0.001).

scholarly journals Proteolytic behavior of isolated Pseudomonas spp. from refrigerated raw milk in different concentrations and storage temperatures

2018 ◽  
Vol 39 (1) ◽  
pp. 419
Author(s):  
Ana Cristina Pinesso Ribeiro ◽  
Samera Rafaela Bruzaroski ◽  
Flavia De Almeida Bergonse Pereira ◽  
Fernanda Gonzales Paião ◽  
Regina Celia Poli-Frederico ◽  
...  
Keyword(s):  
Storage Time ◽  
Storage Temperature ◽  
Population Control ◽  
Milk Powder ◽  
Raw Milk ◽  
Initial Population ◽  
Initial Inoculum ◽  
Pseudomonas Spp ◽  
Cell Counts ◽  
Significant Difference

The objective of the work was to evaluate the multiplication capacity and proteolytic activity of different Pseudomonas spp. cell counts inoculated in milk and storaged under different temperature. Strains isolated from refrigerated raw milk (RRM) were confirmed at genus level by Polymerase Chain Reaction (PCR). The Pseudomonas spp. was cultured in cephalothin-sodium fusidate-cetrimide (CFC) agar-base (30?C for 48 h) until it reached 2 log and 6 log CFU mL-1. Three of eight strains confirmed as Pseudomonas spp were inoculated in sterile reconstituted whole milk powder and incubated at 2°C, 4°C, and 8°C for 96 h. Primary proteolysis indices was determined by the Kjeldahl method. When taking into account the effect of storage time in Pseudomonas spp. population, it was found that the initial population (2 log CFU mL-1) showed significant difference in growth rates only from 0 h to 24 h, keeping at the same levels along 96 h. When a higher initial population was incubated (6 log CFU mL-1), it was not observed a significant difference for times tested. Related to the effect of storage time in proteolysis index, it was not observed a significant difference in samples inoculated with 2 and 6 log CFU mL-1 Pseudomonas spp. When we analyzed the influence of storage temperature on the bacterial multiplication, there was a significant difference in the Pseudomonas spp. population only between 2°C and 8°C after 96 h of milk storage with 2 log CFU/mL of initial inoculum. If we consider the temperature effect in the primary proteolysis index, there were significant differences at the inoculum of 2 log CFU mL-1 where the primary proteolysis at 24 h was lower at 2°C than at 8ºC. Low temperatures or short storage time had no influence on Pseudomonas spp. enumeration or in the primary proteolysis index when high initial contaminations are observed. At lower Pseudomonas spp. initial population, the smaller storage time tested influenced the population control, and linked with the reduction in the storage temperature, lower proteolysis index were observed.

scholarly journals Pseudomonas spp. and P. fluorescens: population in refrigerated raw milk

2017 ◽  
Vol 47 (1) ◽  
Author(s):  
Kelly Molin de Almeida ◽  
Samera Rafaela Bruzaroski ◽  
Daniel Zanol ◽  
Marcela de Melo ◽  
Joice Sifuentes dos Santos ◽  
...  
Keyword(s):  
Titratable Acidity ◽  
Dairy Farms ◽  
Raw Milk ◽  
Quality Parameters ◽  
Pseudomonas Spp ◽  
Psychrotrophic Bacteria ◽  
Milk Samples ◽  
Bulk Milk ◽  
Colony Forming Units ◽  
Bulk Tank

ABSTRACT: Raw milk samples were collected from cooling tanks (after they cooled for 48 h) in five dairy farms and the corresponding bulk tank (bulk milk transportation, BMT) when they arrived to the industry. Routine physical chemical analyzes and quantification of psychrotrophic ( Pseudomonas spp. and P. fluorescens ) and aerobic mesophilic (AM) populations were performed. Only relative density and titratable acidity values for samples of milk from three farms were in agreement to the quality parameters required by law. In the BMT, only the protein content has not reached the minimum value established by law, and counting was performed for AM (>105 colony forming units (CFU) mL-1) and psychrotrophic bacteria (2.8x106CFU mL-1). Pseudomonas spp. counting corresponded to 17.9% of the psychrotrophic population, and P. fluorescens was 3.4% of Pseudomonas spp . count. In milk samples from dairy farms, counts were variable for AM (3.4x105 to 3.7 x107CFU mL-1), psychrotrophic (4.0x104 to 3.1x106CFU mL-1), Pseudomonas spp. (2.3x104 to 1.8x105CFU mL-1), and P. fluorescens (62 to 8.4x103CFU mL-1). For the populations studied, no statistical difference (P>0.05) was observed between counts reported in milk samples collected in dairy farms (cooling tanks) and BMT. Therefore, the genera Pseudomonas spp. and P. fluorescens were not the most frequent psychrotrophic bacteria in this studied milk transportation line.

scholarly journals CONFORMITY OF REFRIGERATED RAW MILK FROM FAMILY PRODUCTION UNITS OF SOUTHERN ESPÍRITO SANTO

2018 ◽  
Vol 19 (0) ◽  
Author(s):  
Leticia Ricieri Bastos ◽  
Thallis Abdalla de Oliveira Prata ◽  
Fabrizio Raggi Abdallah ◽  
Bevaldo Martins Pacheco ◽  
Patricia Campos Bernardes ◽  
...  
Keyword(s):  
Titratable Acidity ◽  
Raw Milk ◽  
Plate Count ◽  
Milk Analysis ◽  
Dry Extract ◽  
Espírito Santo ◽  
Psychrotrophic Bacteria ◽  
Legal Standards ◽  
Standard Values ◽  
Espirito Santo

Abstract Dairy farming is an important activity in Brazil and Espírito Santo state, with small properties accounting for 80% of production. Despite of this economic importance, data about quality of the milk produced and the hygienic-sanitary conditions are still scarce. Then, the objective of this study was to evaluate the characteristics of refrigerated raw milk produced in family production units in southern Espírito Santo to verify compliance with Brazilian legal standards. Three collections were carried out in 29 community expansion tanks, for a total of 87 samples of refrigerated raw milk. Analysis of standard plate count (SPC), psychrotrophic bacteria count (PBC), somatic cell count (SCC), titratable acidity, density, fat, total dry extract (TDE), non-fat dry extract (NFDE), residues of antibiotics (β-lactam and tetracycline), cadmium and lead levels were performed. Of the 87 samples, 66% presented non-standard values for SPC, and 38% had non-standard values for SCC. Eighty five percent of the samples presented non-standard results for NFDE, 10.3% for density and 2.3% for titratable acidity. All samples complied with the legislation regarding residues of antibiotics, Cd and Pb levels. These results indicated failures in the raw milk obtainment and storage chain from family production units of southern Espírito Santo, Brazil.

scholarly journals Bacteriological Properties Of Udder Surface And Milk Samples From Sheep Farms In Hungary

2020 ◽  
Author(s):  
Andualem Tonamo ◽  
István Komlósi ◽  
Ferenc Peles ◽  
Levente Czeglédi
Keyword(s):  
Raw Milk ◽  
Mean Value ◽  
Plate Count ◽  
Milk Product ◽  
High Quality ◽  
Psychrotrophic Bacteria ◽  
Sheep Milk ◽  
Significant Difference ◽  
The Mean ◽  
Bulk Tank

Abstract Background Ewe milk due to its beneficial composition and properties contributes to the growth of microorganisms. The primary prerequisite for making high-quality sheep milk product is the production of high-quality raw sheep milk by dairy farms. Thus, the aim of this study was to examine the bacteriological properties of the udder surface (US), individual ewe raw milk (IERM) and bulk tank milk (BTM) samples from sheep farms in Hungary. Methods Seventy-seven US, seventy-seven IERM, and ten BTM samples were examined from March 2018 to April 2019. Total plate count (TPC), Enterobacteriaceae count (EBC), Escherichia coli count (ECC), Staphylococcus aureus count (SAC), lactic acid bacteria count (LAB) and psychrotrophic bacteria count (PBC) of different ewe breeds were examined according to ISO standards in four Hungarian sheep farms. The differences in the microbiological status between the breed and farm were considered. Results High counts of TPC (3.2±1.1 lg cfu/cm 2 ) and EBC (2.4±0.7 lg cfu/cm 2 ) were found in Cigája breed of US samples in farm1. TPC of US sample of Lacaune (farm2), Lacaune (farm3) and British milk sheep was 2.7±0.8, 2.2±0.5 and 2.4±0.4 lg cfu/cm 2 , respectively. The mean value of TPC of IERM of Merino, Cigája and Dorper breeds in farm1 was 2.8±1.2, 3.5±1.2 and 3.3±0.7 lg cfu/ml, respectively. There was significant difference (p<0.05) between Merino and Cigája breeds for TPC. Although there was no significant difference (p<0.05) between breeds for EBC, the mean of EBC of IERM samples from Dorper breed was highest in farm1. Comparatively low TPC of IERM of British milk sheep breed was recorded. The mean of TPC of BTM was 7.4±0.6, 6.3±0.4 and 5.2±0.1 in farm2, 3 and 4, respectively. Both LAB and PBC were high in BTM of Lacaune breed. Except for BTM, SAC and ECC were not detected in most US and IERM samples. Conclusion The presence of microorganisms in BTM above the limit indicates high microbial contamination due to poor hygienic conditions during milking and milk handling. Practicing very good hygiene principles at the farms, in handling and transportation of milk, is a must.

Rapid Detection of Psychrotrophic Bacteria In Manufacturing Grade Raw Milks

1991 ◽  
Vol 54 (11) ◽  
pp. 861-867 ◽  
Author(s):  
S. R. TATINI ◽  
P. MEKALA ◽  
A. EL-HABAZ ◽  
M. W. GRIFFITHS
Keyword(s):  
Rapid Detection ◽  
Bacterial Count ◽  
Raw Milk ◽  
Plate Count ◽  
Psychrotrophic Bacteria ◽  
Milk Samples ◽  
Microscopic Count ◽  
Direct Epifluorescent Filter Technique ◽  
Native Microflora

Methods to rapidly assess the bacteriological quality of raw milk were investigated. Whereas direct microscopic count, modified psychrotrophic plate count, and direct epifluorescent filter technique (DEFT) did not correlate well with initial psychrotrophic bacterial count of raw milk, improvements were obtained after preincubation of the milk samples. The best preincubation conditions were identified as 30°C for 6 h, 21°C for 10 h, 13°C for 15 h, 13°C for 20 h, or 7°C for 37 h. The “square root” equation was applied to the data, and a model was produced for predicting growth of the native microflora of raw milk. Using this equation, a DEFT count after preincubation of the milk at 21°C for 10 h could accurately predict the initial psychrotroph count and the count after storage of the milk at 6°C for 48 h.

Incidence and Survival of Listeria monocytogenes in Ready-To-Eat Seafood Products

1997 ◽  
Vol 60 (4) ◽  
pp. 372-376 ◽  
Author(s):  
SUSAN A. MCCARTHY
Keyword(s):  
Listeria Monocytogenes ◽  
Storage Time ◽  
Storage Temperature ◽  
Storage Conditions ◽  
Plate Count ◽  
Standard Plate Count ◽  
Smoked Salmon ◽  
Standard Plate ◽  
Seafood Products ◽  
Survival And Growth

The effects of processing and postprocess storage conditions on the incidence and survival of Listeria monocytogenes on crawfish (Procambaris sp.), crabmeat (Callinectus sapidus), and smoked salmon (Salmo salar) were evaluated. L. monocytogenes was recovered from 3% of whole boiled market crawfish samples and 17% of frozen vacuum-packaged partially cooked crawfish tail meat, but not from boiled crabmeat or smoked salmon. Contamination was most likely due to postprocess handling as commonly used methods of cooking (5 min boil or 20 min steep) reduced L. monocytogenes to nondetectable levels in laboratory-contaminated crawfish. In postprocess storage temperature abuse studies, cooked whole crawfish were inoculated internally and externally with 3.0 log CFU of L. monocytogenes per g and incubated at 22 or 30°C for 6 h. The greatest increase in numbers of cells, 1.9 log CFU/g (determined by standard plate count), occurred at 30°C on externally contaminated crawfish. There was little change in numbers of L. monocytogenes during cold storage (6°C, 5 days; −20°C, 15 days). There was little change in cell numbers associated with products stored at 22 or −20°C. At 6°C, numbers of cells associated with crabmeat increased by 3.8 log MPN/g after 6 days; however, there was no increase in numbers of cells associated with salmon. The results show that the survival and growth characteristics of L. monocytogenes are dependent on storage time and temperature and the nature of the seafood product.

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.

Subpasteurization Heat Treatment to Inactivate Lipase and Control Bacterial Growth in Raw Milk

1982 ◽  
Vol 45 (6) ◽  
pp. 513-515 ◽  
Author(s):  
G. F. SENYK ◽  
R. R. ZALL ◽  
W. F. SHIPE
Keyword(s):  
Heat Treatment ◽  
Lipase Activity ◽  
Raw Milk ◽  
Heat Treatments ◽  
Plate Count ◽  
Psychrotrophic Bacteria ◽  
Standard Plate Count ◽  
Heat Treated ◽  
Standard Plate ◽  
And Control

Raw milk was heat-treated under subpasteurization and suprapasteurization conditions, cooled and stored for up to 72 h at 4.4 and 6.7°C. Milk lipase activity and bacteria counts were monitored in both unheated and heated milks. Inhibition of milk lipase activity ranged from 42 to 98% for treatments of 57.2°C for 10 sec to 73.9°C for 10 sec, respectively. The logs of Standard Plate Count after 72 h of storage at 6.7°C were 6.56, 4.86, 4.31, 4.00 and 2.82 for unheated and 10-sec heat treatments at 57.2, 65.6, 73.9 and 82.2°C, respectively. Psychrotrophic Bacteria Counts were also lower in the heated milks than in the unheated milk. The logs of Psychrotrophic Bacteria Counts after 72 h of storage at 6.7°C were 6.21, 2.45, 2.27, 1.33 and 1.00 for unheated and 10-sec heat treatments at 57.2, 65.6, 73.9 and 82.2°C, respectively. Heat treatment of raw milk supplies would result in limiting action of the milk lipase system and growth of bacteria.

Refrigerated storage of fresh-cut marolo (Annona crassiflora mart.)

2020 ◽  
Vol 10 (2) ◽  
pp. 44-54
Author(s):  
Flávia Della Lucia ◽  
Eric Batista Ferreira ◽  
Sandra Maria Oliveira Morais Veiga ◽  
Luciana Azevedo ◽  
Marcela Aparecida Miranda Moreira ◽  
...  
Keyword(s):  
Storage Time ◽  
Titratable Acidity ◽  
Soluble Solids ◽  
Physical Chemical ◽  
Significant Difference ◽  
Thermotolerant Coliforms ◽  
Fresh Cut ◽  
Annona Crassiflora ◽  
Storage Temperatures

Marolo is a fruit typical of the Brazilian Savanna that is highly appreciated for its exotic flavour, nutritional value and sensory attributes. This study aimed to assess the quality of fresh-cut marolo by checking for possible changes in physical, chemical, microbiological and sensorial characteristics during cold storage (12 days at 0°C, 5°C and 10°C). Firmness varied based on storage time; the fruit softened on the 8th day and then increased in hardness until the end of the study. The lowest storage temperatures reduced the darkening rate of this product. No variations in the levels of soluble solids (12.7 to 14.6°B) or total phenolics (741.06 to 1295.21 mg. GAE.100g-1) were observed. Fruits stored at 10 °C showed an increase in titratable acidity after the 5th day and an increase in pH on the 10th and 12th days. Increases in the soluble pectin (156 to 265.73 mg.100g-1) and total pectins (>1.000 mg.100g-1) were noted. No significant difference was observed in the count of the total and thermotolerant coliforms, and the growth of filamentous fungi and yeasts decreased after storage at 0°C and 5°C after the 5th day. Storage at 5 °C for 5 days was found to be the most efficient set of conditions for maintaining the physical, chemical, microbiological and sensory characteristics of marolo.

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