Natural Microflora of Raw Cow Milk and their Enzymatic Spoilage Potential

Pukančíková, Lucia; Lipničanová, Sabina; Kačániová, Miroslava; Chmelová, Daniela; Ondrejovič, Miroslav

doi:10.1515/nbec-2016-0015

Cited by 14 publications

(12 citation statements)

References 30 publications

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“…In Figure 2, it is possible to observe that the isolate of the present study was grouped with the species Raoultella ornithinolytica and was also 100% compatible with this species in the identification by the identity matrix (Table 2). No previous reports of the production potential of AprX were found, but there is a description of a psychotrophic proteolytic agent of milk in Slovakia (Pukančíková et al 2016).…”

Section: Discussionmentioning

confidence: 99%

Pseudomonas spp. and other psychrotrophic microorganisms in inspected and non-inspected Brazilian Minas Frescal cheese: proteolytic, lipolytic and AprX production potential

et al. 2019

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The most consumed cheese in Brazil, Minas Frescal cheese (MFC) is highly susceptible to microbial contamination and clandestine production and commercialization can pose a risk to consumer health. The storage of this fresh product under refrigeration, although more appropriate, may favor the growth of spoilage psychrotrophic bacteria. The objective of this study was to quantify and compare Pseudomonas spp. and other psychrotrophic bacteria in inspected and non-inspected MFC samples, evaluate their lipolytic and proteolytic activities and their metalloprotease production potentials. Twenty MFC samples were evaluated: 10 inspected and 10 non-inspected. Counts of psychrotrophic bacteria and Pseudomonas spp., evaluation of the proteolytic and lipolytic potential of the isolates, and identification of potential producers of alkaline metalloprotease (AprX) were assessed. The mean total psychrotrophic counts were 1.07 (±2.18) × 109CFU/g in the inspected samples and 4.5 (±5.86) × 108CFU/g in the non-inspected, with no significant difference (p=0.37). The average score of Pseudomonas spp. was 6.86 (±18.6) × 105 and 2.08 (±3.65) × 106 CFU/g for the inspected and non-inspected MFC samples, respectively, with no significant difference (p=0.1). Pseudomonas spp. represented 0.06% and 0.004% of psychrotrophic bacteria found in inspected and non-inspected MFC samples, respectively. Collectively, 694 psychrotrophic strains and 47Pseudomonas spp. were isolated, of which 59.9% and 68.1% were simultaneously proteolytic and lipolytic, respectively. Of the 470 psychrotrophs isolated from inspected and 224 from non-inspected cheese samples, 5.74% and 2.23% contained aprX, respectively, while 100 and 86.96% of the Pseudomonas spp. isolates in inspected and non-inspected cheese samples contained the gene. The production potential of AprX did not, however, determine the proteolytic activity on plates of these isolates under the conditions evaluated in this study. Of total, 65.63% of the psychrotrophs that contained aprX gene were confirmed as Pseudomonas spp., using genus-specific PCR. Phylogenetic analysis of the 16S rRNA gene of the other psychrotrophs that were potential producers of AprX identified them as Serratia spp. (n=7), Raoultella ornithinolytica (n=1), and Acinetobacter schindleri (n=1) in the inspected samples and Psychrobacter sanguinis (n=1) and Leuconostoc mesenteroides (n=1) in the non-inspected samples. The production conditions of Brazilian MFC of these samples, while meeting the legal determinations, are not sufficient to control Pseudomonas and other spoilage-related psychrotrophs. Thus, stricter hygienic measures are required during the formal production of this type of cheese.

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Section: Discussionmentioning

confidence: 99%

Pseudomonas spp. and other psychrotrophic microorganisms in inspected and non-inspected Brazilian Minas Frescal cheese: proteolytic, lipolytic and AprX production potential

et al. 2019

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“…In pastures, raw milk is rapidly cooled after being collected and temporarily stored in milk tanks at 4-8 • C. After that, it is transferred to a milk tank truck and transported to the dairy processing plant in the cold chain. During this process, raw milk may be stored at a low temperature for 24-72 h. Psychrophilic bacteria in raw milk, including Pseudomonas and Acinetobacter, can proliferate in large quantities [133][134][135]. These Gramnegative bacteria can live in a low-temperature storage environment, release protease and lipase to reduce the quality of milk, and secrete extensive levels of endotoxin into dairy products during sterilization.…”

Section: Raw Milk Managementmentioning

confidence: 99%

Effect of Food Endotoxin on Infant Health

Wang

et al. 2021

Toxins

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Endotoxin is a complex molecule derived from the outer membrane of Gram-negative bacteria, and it has strong thermal stability. The processing of infant food can kill pathogenic bacteria but cannot remove endotoxin. Because the intestinal structure of infants is not fully developed, residual endotoxin poses a threat to their health by damaging the intestinal flora and inducing intestinal inflammation, obesity, and sepsis, among others. This paper discusses the sources and contents of endotoxin in infant food and methods for preventing endotoxin from harming infants. However, there is no clear evidence that endotoxin levels in infant food cause significant immune symptoms or even diseases in infants. However, in order to improve the safety level of infant food and reduce the endotoxin content, this issue should not be ignored. The purpose of this review is to provide a theoretical basis for manufacturers and consumers to understand the possible harm of endotoxin content in infant formula milk powder and to explore how to reduce its level in infant formula milk powder. Generally, producers should focus on cleaning the milk source, securing the cold chain, avoiding long-distance transportation, and shortening the storage time of raw milk to reduce the level of bacteria and endotoxin. After production and processing, the endotoxin content should be measured as an important index to test the quality of infant formula milk powder so as to provide high-quality infant products for the healthy growth of newborns.

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“…Porém, suas enzimas podem ser termoestáveis, permanecendo ativas mesmo após a destruição dos microrganismos a elas associados. É o caso de algumas proteases produzidas pelos microrganismos psicrotróficos, que podem estar presentes nos derivados lácteos e continuar o processo de degradação (BAUR et al, 2015;PUKANČÍKOVÁ et al, 2016;VON NEUBECK, et al, 2015;MARCHAND et al, 2017).…”

Section: Introductionunclassified

Avaliação das características físico-químicas de iogurtes naturais produzidos a partir de leite contaminado por bactérias psicrotróficas proteolíticas/ Physicochemical evaluation of plain yogurt produced by psychrotrophic and proteolytic bacteria contaminated milk

Goulart¹,

Barreto²,

Moraes³

et al. 2021

BJDV

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Cooling of milk in dairy favors the multiplication of psychrotrophicbacteria that can produce thermoresistant proteolytic enzymes and degrade milk components. To verify the effects of these enzymes in dairy products, this study aimed to evaluate the physicalchemical characteristics of plain yogurt produced from milk contaminated with proteolytic psychrotrophic bacteria. For this, psychrotrophicbacteria producing proteolytic enzymes were isolated from raw milk, having been identified like Pseudomonassp., Alcaligenes sp. and Butiauxella sp. These microorganisms were inoculated in pasteurized milk and stored for 48 and 72 hours at a temperature of 7°±1°C. After the storage, the milk was heated to 90°± 5°C for 10 min and immediately cooled to 43°C. The ingredients were added and plain yogurts were produced, and then evaluated for their protein, fat and acidity contents. The plain yogurts produced, in terms of fat and protein contents, were significantly higher in yogurts produced with control milk (not inoculated). In addition, the acidity of yogurt produced with milk stored for 72 hours at 7°±1°C was significantly higher on day zero, regardless of the microorganisms intentionally added. Thus, it can be concluded that the physical-chemical characteristics of plain yoghurts produced with contaminated milks were different from those obtained from yogurts produced with non-contaminated milks, being important to reflection of the cold storage periods due to the favoring of multiplication of proteolytic psychrotrophic microorganism.

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Natural Microflora of Raw Cow Milk and their Enzymatic Spoilage Potential

Cited by 14 publications

References 30 publications

Pseudomonas spp. and other psychrotrophic microorganisms in inspected and non-inspected Brazilian Minas Frescal cheese: proteolytic, lipolytic and AprX production potential

Pseudomonas spp. and other psychrotrophic microorganisms in inspected and non-inspected Brazilian Minas Frescal cheese: proteolytic, lipolytic and AprX production potential

Effect of Food Endotoxin on Infant Health

Avaliação das características físico-químicas de iogurtes naturais produzidos a partir de leite contaminado por bactérias psicrotróficas proteolíticas/ Physicochemical evaluation of plain yogurt produced by psychrotrophic and proteolytic bacteria contaminated milk

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