Analysis of Raw Milk Quality at Reception and During Cold Storage: Combined Effects of Somatic Cell Counts and Psychrotrophic Bacteria on Lipolysis

Gargouri, Ali; Hamed, Houda; Elfeki, Abdelfettah

doi:10.1111/1750-3841.12188

Cited by 26 publications

(34 citation statements)

References 59 publications

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“…In addition, milk supplied to the farm is not always immediately processed. In particular, the storage conditions and storage time before the processing can favor the growth and the development of minor microbiota which can become dominant, leading to unacceptable quality of the final dairy product (42,43).…”

Section: Discussionmentioning

confidence: 99%

Microbiota of an Italian Grana-Like Cheese during Manufacture and Ripening, Unraveled by 16S rRNA-Based Approaches

Alessandria

Ferrocino

Filippis

et al. 2016

Appl Environ Microbiol

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The microbial ecology of cheese involves a rich and complex interaction between starter lactic acid bacteria and nonstarter lactic acid bacteria (NSLAB), mainly originating from raw milk and/or from the environment, that can contribute to the final characteristics of cheese. The aim of the present research was the exploration of the active microbiota by RNA-based approaches during the manufacturing and ripening of a Grana-like cheese. Reverse transcriptase PCR (RT-PCR)-denaturing gradient gel electrophoresis (DGGE) and RNA-based high-throughput sequencing were applied to profile microbial populations, while the enumeration of active bacteria was carried out by using quantitative PCR (qPCR). Three different cheese productions (named D, E, and F) collected in the same month from the same dairy plant were analyzed. The application of the qPCR protocol revealed the presence of 7 log CFU/ml of bacterial load in raw milk, while, during ripening, active bacterial populations ranged from <4 to 8 log CFU/ml. The natural whey starters used in the three productions showed the same microbiota composition, characterized by the presence of Lactobacillus helveticus and Lactobacillus delbrueckii. Nevertheless, beta-diversity analysis of the 16S rRNA sequencing data and RT-PCR-DGGE showed a clear clustering of the samples according to the three productions, probably driven by the different milks used. Milk samples were found to be characterized by the presence of several contaminants, such as Propionibacterium acnes, Acidovorax, Acinetobacter, Pseudomonas, and NSLAB. The core genera of the starter tended to limit the development of the spoilage bacteria only in two of the three batches. This study underlines the influence of different factors that can affect the final microbiota composition of the artisanal cheese. IMPORTANCEThis study highlights the importance of the quality of the raw milk in the production of a hard cheese. Independent from the use of a starter culture, raw milk with low microbiological quality can negatively affect the populations of lactic acid bacteria and, as a consequence, impact the quality of the final product due to metabolic processes associated with spoilage bacteria. G rana-like hard cheese is a typical raw cow's milk cheese produced in the Piedmont region in northwest Italy. Curd fermentation is carried out by natural thermophilic whey cultures obtained from the manufacturing of the previous day, after heating at 53 to 55°C, and the ripening is commonly carried out for 12 months.Natural whey starters (NWS) are used for several protected designation of origin (PDO) cheeses. They are usually dominated by thermophilic lactic acid bacteria (LAB), but subdominant species, including mesophilic LAB, may also occur. NWS have a complex microbial association of various species as well as a large number of biotypes (1).Temperature is the main factor associated with the variability of the microbiota composition of the NWS. Cooking treatment and whey cooling lead to the selection of a characteristic mi...

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Section: Discussionmentioning

confidence: 99%

Microbiota of an Italian Grana-Like Cheese during Manufacture and Ripening, Unraveled by 16S rRNA-Based Approaches

Alessandria

Ferrocino

Filippis

et al. 2016

Appl Environ Microbiol

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“…Microbial diversity in raw milk has been targeted in several studies (Martins and others ; Delbès and others ; Ercolini and others ; Giannino and others ; Rasolofo and others ; Raats and others ) as well as the effect of cold storage on bacterial community and raw milk quality (Wiking and others ; Kumaresan and others ; De Jonghe and others ; Perin and others ; Gargouri and others ; Izidoro and others ). However, the goal of this study, contrary to the majority of the previous ones, was to assess the Brazilian raw milk quality and to identify the predominant psychrotrophic heat‐resistant proteolytic enzymes producers during cold storage using molecular methods in addition to miniaturized phenotypic kits.…”

Section: Discussionmentioning

confidence: 99%

Pseudomonas spp. and Serratia liquefaciens as Predominant Spoilers in Cold Raw Milk

Machado

Silva

Bazzolli

et al. 2015

Journal of Food Science

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The storage of fresh raw milk at low temperature does not prevent proliferation of psychrotrophic bacteria that can produce heat-resistant proteolytic enzymes contributing to the reduced shelf life of dairy products. This study aimed to identify the dominant psychrotrophic proteolytic enzyme-producing population of raw milk from Brazil. Raw milk samples collected in 3 different cooling tanks in Brazil were stored at optimal (45 h at 4 °C followed by 3 h at 7 °C) and suboptimal (45 h at 7 °C followed by 3 h at 10 °C) conditions to simulate farm storage and transportation allowed by Brazilian laws. The highly proteolytic enzyme-producing strains isolated from stored cold raw milk were characterized by repetitive sequence-based Polymerase Chain Reaction (PCR) analysis. This clustering resulted in 8 different clusters and 4 solitary fingerprints. The most proteolytic isolates from each rep-cluster were selected for identification using miniaturized kit, 16S rDNA and rpoB gene sequencing. Serratia liquefaciens (73.9%) and Pseudomonas spp. (26.1%) were identified as the dominant psychrotrophic microorganisms with high spoilage potential. The knowledge of milk spoilage microbiota will contribute to improved quality of milk and dairy products.

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“…As a result, the analysis of the Standard Plate Count (SPC) is a good indicator of the state of hygiene at the dairy farm level during the phases of milking, storage, and transportation (9) . The SPC analysis determines the concentration of microorganisms present in the milk and is a good tool for dairy hygiene quality inspectors to infer the likely adverse effect that a specific batch might have on a processing plant and the overall safety of the milk (10) . Higher milk hygiene at farm level provides the industry with better product to process resulting in products with longer shelf-life.…”

Section: Introductionmentioning

confidence: 99%

QUALITY OF REFRIGERATED RAW MILK FROM BUFFALO COWS (Bubalus bubalis bubalis) IN DIFFERENT FARMS AND SEASONS IN BRAZIL

et al. 2017

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The present research aimed to examine the chemical and microbiological characteristics of refrigerated raw milk collected from buffalo-only dairy herds from different farms and seasons. Samples were collected from twelve farms producing buffalo milk, located in the Mideast region of São Paulo state, in Brazil, once a month throughout the dairy calendar year from 2011 to 2014. The analysis of fat, protein, lactose, dry extract, and total solids contents were carried out using Infrared Absorption. Residues for antimicrobial analysis were carried out using Delvo Test Kit technique, and both somatic cell count and standard plate count analysis were carried out using Flow Cytometry. The analysis of the chemical components as well as for the microbiological analysis of SPC proved to be statistically significant throughout the period. No antibiotic residues were found in the totality of the sample, hence indicating that the farmers complied with the current sanitary legislation in that country, as well as SCC; however, higher values were found for the SPC. Significant results for all parameters analyzed were found among the farms, indicating that price incentives paid for the quality of raw milk could be an alternative to dairy processing companies, favoring yield and quality of the final product. Keywords: Brazil; chemical parameters; dairy; microbiological parameters; monitoring. ResumoO presente estudo objetivou examinar as características químicas e microbiológicas do leite cru refrigerado coletado em diferentes fazendas e estações. Amostras foram coletadas em doze fazendas 2 Cienc. anim. bras., Goiânia, v.18, 1-12, e-41815, 2017Quality of refrigerated raw milk from buffalo cows… produtoras de leite de búfala localizadas na região centro-leste do estado de São Paulo, Brasil, uma vez ao mês entre os anos de 2011 a 2014. Análises de gordura, proteína, lactose, extrato seco e sólidos totais foram realizadas utilizando-se técnica de Infra-vermelho. Análises de resíduos de antimicrobianos foram realizadas através do teste rápido Kit Delvo Test. Análises de contagem de células somáticas e contagem padrão em placas foram conduzidas através de Citometria de Fluxo. Resultados das análises dos componentes químicos, assim como da análise microbiológica de CPP, demonstraram diferenças estatísticas significativas através das estações para estes parâmetros. Em todas as amostras analisadas nenhum resíduo de antimicrobiano foi detectado, indicando que os produtores estão respeitando a legislação sanitária brasileira vigente, bem como para SCC; no entanto, valores acima do permitido foram encontrados para CPP. Diferenças significativas para todos os parâmetros analisados foram encontradas entre as fazendas investigadas, indicando que o incentivo de preço pago pela qualidade do leite cru poderia ser uma alternativa às empresas de processamento de lácteos, favorecendo o rendimento e a qualidade do produto final. Palavras-chave: Brasil; laticínio; monitoramento; parâmetros químicos; parâmetros microbiológicos.

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Analysis of Raw Milk Quality at Reception and During Cold Storage: Combined Effects of Somatic Cell Counts and Psychrotrophic Bacteria on Lipolysis

Cited by 26 publications

References 59 publications

Microbiota of an Italian Grana-Like Cheese during Manufacture and Ripening, Unraveled by 16S rRNA-Based Approaches

Microbiota of an Italian Grana-Like Cheese during Manufacture and Ripening, Unraveled by 16S rRNA-Based Approaches

Pseudomonas spp. and Serratia liquefaciens as Predominant Spoilers in Cold Raw Milk

QUALITY OF REFRIGERATED RAW MILK FROM BUFFALO COWS (Bubalus bubalis bubalis) IN DIFFERENT FARMS AND SEASONS IN BRAZIL

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