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

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.

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Proteolytic and lipolytic microbiota of refrigerated raw milk from northeast and southern regions of Brazil

Semina Ciências Agrárias ◽

10.5433/1679-0359.2015v36n6supl2p4289 ◽

2015 ◽

Vol 36 (6Supl2) ◽

pp. 4289 ◽

Cited By ~ 1

Author(s):

Jose Carlos Ribeiro Junior ◽

Joyce Bitencourt Atayde Lima ◽

Kleydejany Lima de Lemos ◽

Livia Cavaletti Corrêa da Silva ◽

Ronaldo Tamanini ◽

...

Keyword(s):

Shelf Life ◽

Microbiological Quality ◽

Raw Milk ◽

The State ◽

Advanced Technology ◽

Daily Production ◽

Pasteurized Milk ◽

Hygiene Practices ◽

Spoilage Microorganisms

<p>The shelf life of milk and milk derivatives is directly related to the microbiological quality of refrigerated raw milk. Spoilage microorganisms with proteolytic and/or lipolytic properties are primarily responsible for the decrease in the quality of milk, which is reflected in the shelf life of pasteurized milk and all derivatives. The aim of this study was to determine the spoilage microbial load of refrigerated raw milk from the northeast and southern regions of Brazil, which have different climatic and technological conditions of production. We evaluated 46 samples of milk from the state of Paraná in the southern region, and 10 samples of milk from the state of Maranhão in the northeast region, totaling 56 samples collected from November 2013 to November 2014. The producers of Paraná were divided into large (20) or small (26) according to the average daily production. All producers of Maranhão were considered small (<500L/day). The proteolytic and lipolytic microorganism counts were conducted in milk agar and tributyrin agar, respectively. Milk from the large producers of Paraná had average counts of 1.4 × 104 CFU/mL for proteolytic microorganisms and 1.2 × 103 CFU/mL for lipolytics microorganisms, significantly (p <0.05) lower than the small producers in the same state, and the producers of Maranhão. Producers of Maranhao had counts of 1.1 × 105 CFU/mL for proteolytic microorganisms and 2 × 105 CFU/mL for lipolytic microorganisms, with the proteolytic count significantly lower than that of small Paraná producers. The amount of proteolytic and lipolytic spoilage microorganisms in milk is influenced by the adaptation of the microorganisms to cold, promoted by the cooling of milk, which is practiced less frequently in the country’s northeastern region. The amount of spoilage microorganisms is also affected by the implementation of milking hygiene practices, which reduce contamination. Such practices are more frequently and efficiently implemented among large producers with more advanced technology, which can improve the microbiological quality of raw milk, thus increasing the shelf life of pasteurized milk, and reducing problems in UHT milk as well as milk derivatives. </p>

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Proteolytic and lipolytic microbiota of refrigerated raw milk from northeast and southern regions of Brazil

Semina Ciências Agrárias ◽

10.5433/1679-0359.2015v36n6sup2p4289 ◽

2015 ◽

Vol 36 (6Supl2) ◽

pp. 4289

Author(s):

Jose Carlos Ribeiro Junior ◽

Joyce Bitencourt Atayde Lima ◽

Kleydejany Lima de Lemos ◽

Livia Cavaletti Corrêa da Silva ◽

Ronaldo Tamanini ◽

...

Keyword(s):

Shelf Life ◽

Microbiological Quality ◽

Raw Milk ◽

The State ◽

Advanced Technology ◽

Daily Production ◽

Pasteurized Milk ◽

Hygiene Practices ◽

Spoilage Microorganisms

The shelf life of milk and milk derivatives is directly related to the microbiological quality of refrigerated raw milk. Spoilage microorganisms with proteolytic and/or lipolytic properties are primarily responsible for the decrease in the quality of milk, which is reflected in the shelf life of pasteurized milk and all derivatives. The aim of this study was to determine the spoilage microbial load of refrigerated raw milk from the northeast and southern regions of Brazil, which have different climatic and technological conditions of production. We evaluated 46 samples of milk from the state of Paraná in the southern region, and 10 samples of milk from the state of Maranhão in the northeast region, totaling 56 samples collected from November 2013 to November 2014. The producers of Paraná were divided into large (20) or small (26) according to the average daily production. All producers of Maranhão were considered small (<500L/day). The proteolytic and lipolytic microorganism counts were conducted in milk agar and tributyrin agar, respectively. Milk from the large producers of Paraná had average counts of 1.4 × 104 CFU/mL for proteolytic microorganisms and 1.2 × 103 CFU/mL for lipolytics microorganisms, significantly (p <0.05) lower than the small producers in the same state, and the producers of Maranhão. Producers of Maranhao had counts of 1.1 × 105 CFU/mL for proteolytic microorganisms and 2 × 105 CFU/mL for lipolytic microorganisms, with the proteolytic count significantly lower than that of small Paraná producers. The amount of proteolytic and lipolytic spoilage microorganisms in milk is influenced by the adaptation of the microorganisms to cold, promoted by the cooling of milk, which is practiced less frequently in the country’s northeastern region. The amount of spoilage microorganisms is also affected by the implementation of milking hygiene practices, which reduce contamination. Such practices are more frequently and efficiently implemented among large producers with more advanced technology, which can improve the microbiological quality of raw milk, thus increasing the shelf life of pasteurized milk, and reducing problems in UHT milk as well as milk derivatives.

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

Stamford Journal of Microbiology ◽

10.3329/sjm.v4i1.22753 ◽

2015 ◽

Vol 4 (1) ◽

pp. 5-8 ◽

Cited By ~ 5

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

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

Journal of Food Protection ◽

10.4315/0362-028x-71.8.1580 ◽

2008 ◽

Vol 71 (8) ◽

pp. 1580-1589 ◽

Cited By ~ 60

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.

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Physical and microbial qualities of raw milk collected from Bangladesh Agricultural University dairy farm and the surrounding villages

Bangladesh Journal of Veterinary Medicine ◽

10.3329/bjvm.v6i2.2339 ◽

1970 ◽

Vol 6 (2) ◽

pp. 217-221 ◽

Cited By ~ 3

Author(s):

MTG Khan ◽

MA Zinnah ◽

MP Siddique ◽

MHA Rashid ◽

MA Islam ◽

...

Keyword(s):

Microbiological Quality ◽

Dairy Farm ◽

Raw Milk ◽

Viable Count ◽

Physical Parameters ◽

Total Viable Count ◽

Coliform Count ◽

Milk Samples

The present study was undertaken with the aim of investigating the physical parameters (e.g. organoleptic and specific gravity of raw milk) and also to study the microbiological quality of raw milk (total viable count, Coliform count and Staphylococcal count) from different villages and Bangladesh Agricultural University (BAU) Dairy Farm of Mymensingh District of Bangladesh, during the period from July to November 2007. A total number of 100 raw milk samples were collected at morning and evening from BAU dairy farm and surrounding four villages of BAU campus. The organoleptic and bacteriological qualities of each sample were analyzed. The organoleptic examination included taste panel score to assess consumer's acceptance and the bacteriological analysis comprised enumeration of total viable count (TVC), total colifrom count (TCC) and total staphylococcal count (TSC) for the determination of sanitary quality. The organoleptic quality of the milk samples is more or less same except the Churkhai milk samples which had flat taste (in 16% milk sample). The average values of TVC/ml were log 5.920, 5.934, 6.007, 6.075 and 6.127 for BAU Dairy Farm, Boira, Shutiakhali, Churkahai and Paglabazar respectively; coliform count were log 2.501, 2.522, 2.550, 2.620 and 2.619 respectively; staphylococcal count were log 2.832, 2.812, 2.866, 2.931 and 2.988 respectively. So, it may be concluded that the raw milk samples of BAU Dairy Farm were superior to others collected from the selected villages which may be due to maintaining better hygienic condition. Key words: Raw milk, physical and microbial quality Â doi: 10.3329/bjvm.v6i2.2339 Bangl. J. Vet. Med. (2008). 6 (2): 217-221

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The effect of breed and stage of lactation on the microbiological status of raw milk

Acta Agraria Debreceniensis ◽

10.34101/actaagrar/1/2367 ◽

2019 ◽

pp. 37-45

Author(s):

Flóra Mária Petróczki ◽

Tema Andualem Tonamo ◽

Béla Béri ◽

Ferenc Peles

Keyword(s):

Microbiological Quality ◽

Raw Milk ◽

Coliform Count ◽

Milk Samples ◽

Stage Of Lactation ◽

Holstein Friesian ◽

Significant Difference ◽

Jersey Cows ◽

Friesian Cows

The microbiological quality of the milk is important not only for food safety, but it can also influence the quality of dairy products. The microbiological status of raw cow milk can be influenced by many factors. Our aim was to determine whether there was a difference between the microbiological quality of milk of two different cow breeds (Holstein Friesian and Jersey) kept and milked in the same conditions, and how the microbiological quality of the raw cow milk changed during lactation (beginning, mid, and end). Samples were taken and analysed in July, August and September in 2018 from two dairy farms in Hajdú-Bihar county. During the conducted studies, the total plate count (TPC), the coliform count, the Staphylococcus aureus count and the coagulase-negative Staphylococcus (CNS) count of raw milk samples were determined. There was no significant difference (P>0.05) between the milk of the Holstein Friesian and Jersey breeds in the case of TPC. However, the mean coliform count of milk samples taken from Holstein Friesian cows was significantly lower (P<0.05) than the mean coliform count of milk samples taken from Jersey cows. S. aureus was detected in one of the twelve milk samples taken from Holstein Friesian cows, and in two of the eleven milk samples taken from Jersey cows. CNS was found in larger amount in milk samples taken from Holstein Friesian cows, and the difference was significant (P<0.05). Both TPC and CNS count were significantly higher (P<0.05) in individual milk samples taken at the end stage of lactation, than in samples taken in the earlier stages of lactation from Farm “A”. However, in the case of Farm “B”, there was no significant difference (P>0.05) in colony counts at different stages of lactation. S. aureus was only present in milk samples that collected from cows, which were at the beginning and middle stages of lactation. Testimg the hemolysin production ability of S. aureus strains isolated from the raw milk samples, only weak hemolysis was observed on blood agar. In case of antibiotic resistance testing, it was found that all strains were susceptible to cefoxitin, chloramphenicol, clindamycin, erythromycin, gentamicin, penicillin G, tetracycline and trimethoprim/sulphamethoxazole. Based on the results of our studies, staphylococci were detected in a higher amount in the milk of Holstein Friesian cows, and coliform bacteria were detected in a higher number in the milk of Jersey cows. Summing up the results of the milk samples taken from the different stages of lactation in one of the farms, it can be concluded that higher TPC and CNS count could be detected at the end stage of lactation than in the samples taken from the earlier stages of lactation. The fact that at the end of lactation the microorganisms could be detected in a higher colony count may be related to the fact that teats could be damaged during lactation by the milking machine, which increased the chance of imvading the microorganisms into the udder.

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Rapid and Simple Estimation of Microbiological Quality of Raw Milk Using Chromogenic Limulus Amoebocyte Lysate Endpoint Assay

Journal of Food Protection ◽

10.4315/0362-028x-65.9.1447 ◽

2002 ◽

Vol 65 (9) ◽

pp. 1447-1451 ◽

Cited By ~ 7

Author(s):

MIN-SUK RHEE ◽

DONG-HYUN KANG

Keyword(s):

Microbiological Quality ◽

Free Water ◽

Raw Milk ◽

Microtiter Plate ◽

Data Set ◽

Milk Samples ◽

Limulus Amoebocyte Lysate ◽

Endpoint Assay ◽

Lal Assay

A rapid chromogenic Limulus amoebocyte lysate (LAL) endpoint assay for the enumeration of total mesophilic microbial loads and coliforms was investigated as a means to assess the microbiological quality of raw milk. For experiment 1, raw milk samples (n = 25) were stored in a refrigerator (2 ± 2°C) and then analyzed at regular intervals (1, 5, 10, and 15 days). For experiment 2, fresh raw milk samples (n = 50) were tested to determine the utility of the LAL assay for fresh raw milk. The sample was diluted threefold in a 96-well microtiter plate with pyrogen-free water and assayed with a chromogenic LAL kit to find a final reaction point. The LAL results were compared with standard plate counts (SPC) and coliform counts determined by conventional plating methods. The results of the LAL assay were strongly correlated to conventional SPC (r2 = 0.93; n = 100) and were highly correlated to coliforms (r2 = 0.74; n = 100). A highly significant linear relationship (r2 = 0.82; n = 50) was also observed between the predicted SPC based on the LAL value and the actual SPC. The results of LAL testing were classified into one of seven contamination groups. The data set for SPC was effectively differentiated using the LAL technique (P < 0.01). The chromogenic LAL assay was found to be a rapid (within 16 min) and simple (not requiring specific instruments) method for monitoring microbial levels in raw milk. This method may be successfully implemented to rapidly determine highly microbial contaminated raw milk (>3.0 log10 CFU/ml of SPC).

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Microbiological quality of refrigerated raw milk in the dairy farm and after transport to the processing dairy plant

Arquivos do Instituto Biológico ◽

10.1590/1808-1657000422016 ◽

2018 ◽

Vol 84 (0) ◽

Author(s):

Vivian Mörschbächer ◽

Claudete Rempel ◽

Mônica Maciel

Keyword(s):

Low Temperatures ◽

Microbiological Quality ◽

Dairy Farm ◽

Raw Milk ◽

Raw Material ◽

Processing Plant ◽

Milk Samples ◽

Dairy Plant ◽

The Mean

ABSTRACT: Transport of cooled raw milk in bulk has greatly improved the quality of the raw material collected by dairy plants as it reduces the proliferation of mesophilic microorganisms that cause milk acidity and hinder its processing. However, refrigeration has favored the growth of psychrotrophic microorganisms which are able to grow at low temperatures (below 10ºC) and that produce heat resistant enzymes which degrade some milk components, reducing milk shelf life and causing organoleptic changes. The aim of this paper was to evaluate the microbiological quality of raw milk in dairy farms and after its transport to the processing dairy plant, through plate counting of mesophilic and psychrotrophic microorganisms. Fourteen milk samples were collected from tanks of the dairy-farming properties, and one sample was collected from their milk transport tanker at the entrance of the processing plant. Our results showed that the mean number of mesophilic microorganisms was higher in samples collected straight from the dairy farm tanks than in the samples collected from the transportation tankers at the entrance of the plant. Of the 14 sampled tanks, 64.3% were non-compliant with legislation. The sample collected from the milk transportation tanker containing milk from all properties showed a higher mean number of psychrotrophic microorganisms than the dairy farm samples. We conclude that the milk from dairy properties showed a higher amount of mesophilic microorganisms, and after transportation, at the entrance of the processing plant, there is a higher amount of psychrotrophic microorganisms.

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MICROBIOLOGICAL QUALITY OF GOAT MILK PRODUCED ON ALAGOAS STATE, BRAZIL

Nucleus Animalium ◽

10.3738/21751463.3613 ◽

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.

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Bacteriological quality of raw milk marketed in and around Guwahati city, Assam, India

Veterinary World ◽

10.14202/vetworld.2021.656-660 ◽

2021 ◽

Vol 14 (3) ◽

pp. 656-660

Author(s):

Smita Kakati ◽

Archana Talukdar ◽

Razibuddin Ahmed Hazarika ◽

Masuk Raquib ◽

Saurabh Kumar Laskar ◽

...

Keyword(s):

Standard Procedure ◽

Raw Milk ◽

Poor Quality ◽

Plate Count ◽

Coliform Count ◽

Standard Plate Count ◽

Milk Samples ◽

Guwahati City ◽

Standard Plate

Background and Aim: Milk is a highly perishable commodity, which is subjected to various types of contamination right from the farm level to the consumers' table. This study aimed to assess the quality of raw milk sold in and around Guwahati city based on the microbial load. Materials and Methods: A total of 200 raw pooled milk samples collected from 25 different locations in and around Guwahati city were subjected to quality evaluation based on the methylene blue reduction test (MBRT), standard plate count, and coliform count as per the standard procedure. Results: Out of the 200 samples evaluated, more than 50% of them were graded as poor to very poor quality based on the MBRT results. None of the samples could be graded as excellent quality and only 14.5% were graded as good quality. The standard plate count and coliform count of all the raw milk samples were found to be significantly higher than the legal standard. A highly significant (p<0.01) difference was observed for standard plate count and coliform count among the different locations in and around Guwahati city. Conclusion: From the present study, it could be inferred that raw milk sold in most parts of Guwahati city do not confer to the legal microbiological standard and may pose a high risk of milk-borne illness among consumers of the city, which needs a systematic series of actions to be implemented properly.

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