Raw milk from vending machines: Effects of boiling, microwave treatment, and refrigeration on microbiological quality

Tremonte, Patrizio; Tipaldi, Luca; Succi, Mariantonietta; Pannella, Gianfranco; Falasca, Luisa; Capilongo, Valeria; Coppola, Raffaele; Sorrentino, Elena

doi:10.3168/jds.2013-7744

Cited by 54 publications

(52 citation statements)

References 21 publications

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“…Similarly to L. innocua , pathogenic L. monocytogenes is frequently found in various foodstuffs (Kovacevic et al, 2012; Jami et al, 2014; Ebner et al, 2015; Melo et al, 2015), especially those characterized by pH values higher than 4.4 (CAC, 2009). In the food industry a number of strategies are used to inhibit the growth of undesirable microorganisms, like technological processing (Tremonte et al, 2014), addition of natural substances (Tipaldi et al, 2011; Tremonte et al, 2016), protective microbial cultures (Sorrentino et al, 2013) as well as organic acids (Davidson et al, 2013). Unfortunately, in the case of several food types, sub-lethal pH values may induce resistance mechanisms to acid stress, which make the cells more resistant to severe acid conditions (Gandhi and Chikindas, 2007).…”

Section: Introductionmentioning

confidence: 99%

Homology-Based Modeling of Universal Stress Protein from Listeria innocua Up-Regulated under Acid Stress Conditions

et al. 2016

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An Universal Stress Protein (USP) expressed under acid stress condition by Listeria innocua ATCC 33090 was investigated. The USP was up-regulated not only in the stationary phase but also during the exponential growth phase. The three dimensional (3D) structure of USP was predicted using a combined proteomic and bioinformatics approach. Phylogenetic analysis showed that the USP from Listeria detected in our study was distant from the USPs of other bacteria (such as Pseudomonas spp., Escherichia coli, Salmonella spp.) and clustered in a separate and heterogeneous class including several USPs from Listeria spp. and Lactobacillus spp. An important information on the studied USP was obtained from the 3D-structure established through the homology modeling procedure. In detail, the Model_USP-691 suggested that the investigated USP had a homo-tetrameric quaternary structure. Each monomer presented an architecture analogous to the Rossmann-like α/β-fold with five parallel β-strands, and four α-helices. The analysis of monomer-monomer interfaces and quality of the structure alignments confirmed the model reliability. In fact, the structurally and sequentially conserved hydrophobic residues of the β-strand 5 (in particular the residues V146 and V148) were involved in the inter-chains contact. Moreover, the highly conserved residues I139 and H141 in the region α4 were involved in the dimer association and functioned as hot spots into monomer–monomer interface assembly. The hypothetical assembly of dimers was also supported by the large interface area and by the negative value of solvation free energy gain upon interface interaction. Finally, the structurally conserved ATP-binding motif G-2X-G-9X-G(S/T-N) suggested for a putative role of ATP in stabilizing the tetrameric assembly of the USP. Therefore, the results obtained from a multiple approach, consisting in the application of kinetic, proteomic, phylogenetic and modeling analyses, suggest that Listeria USP could be considered a new type of ATP-binding USP involved in the response to acid stress condition during the exponential growth phase.

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Section: Introductionmentioning

confidence: 99%

Homology-Based Modeling of Universal Stress Protein from Listeria innocua Up-Regulated under Acid Stress Conditions

et al. 2016

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“…Several studies have been conducted to characterize the psychrotrophic microbiota in milk and to identify the predominant microorganisms after cold storage (Dogan and Boor ; Hantis‐Zacharov and Halpern ; Ercolini and others ; Marchand and others ; Rasolofo and others ; Raats and others ; Tremonte and others ). Hantis‐Zacharov and Halpern () and Raats and others () reported, using culture‐dependent and molecular methods, Pseudomonas , Acinetobacter , and actinobacteria are the dominant groups in Israeli refrigerated milk.…”

Section: Introductionmentioning

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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“…For example, milk may be stored in the door which is likely to be at a higher temperature than the core of the refrigerator (James and James, 2007;Cibin et al, 2013). Tremonte et al (2014) examined raw milk vending machines in southern Italy and found that the milk temperature ranged from 3.5 to 4.1 °C, which was in line with Italian legislation.…”

Section: Temperature Control In Vending Machines and Subsequent Transmentioning

confidence: 54%

“…Other surveys have reported the isolation of pathogens from raw milk sold through vending machines (Giacometti et al, 2012b;Serraino et al, 2013;Gasperetti et al, 2014). Tremonte et al (2014) analysed 30 samples collected from vending machines in southern Italy for indicator microorganisms. In all of the samples, the total mesophilic count (TMC) was around 5 log CFU/mL and increased to over 6 log after 72 hours of storage at 4 °C; counts of Pseudomonas spp.…”

Section: Operation Of Vending Machinesmentioning

confidence: 99%

Scientific Opinion on the public health risks related to the consumption of raw drinking milk

report¹

2015

EFSA Journal

120

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Raw drinking milk (RDM) has a diverse microbial flora which can include pathogens transmissible to humans. The main microbiological hazards associated with RDM from cows, sheep and goats, horses and donkeys and camels were identified using a decision tree approach. This considered evidence of milk-borne infection and the hazard being present in the European Union (EU), the impact of the hazard on human health and whether there was evidence for RDM as an important risk factor in the EU. The main hazards were Campylobacter spp., Salmonella spp., shigatoxin-producing Escherichia coli (STEC), Brucella melitensis, Mycobacterium bovis and tick-borne encephalitis virus, and there are clear links between drinking raw milk and human illness associated with these hazards. A quantitative microbiological risk assessment for these hazards could not be undertaken because country and EU-wide data are limited. Antimicrobial resistance has been reported in several EU countries in some of the main bacterial hazards isolated from raw milk or associated equipment and may be significant for public health. Sale of RDM through vending machines is permitted in some EU countries, although consumers purchasing such milk are usually instructed to boil the milk before consumption, which would eliminate microbiological risks. With respect to internet sales of RDM, there is a need for microbiological, temperature and storage time data to assess the impact of this distribution route. Intrinsic contamination of RDM with pathogens can arise from animals with systemic infection as well as from localised infections such as mastitis. Extrinsic contamination can arise from faecal contamination and from the wider farm environment. It was not possible to rank control options as no single step could be identified which would significantly reduce risk relative to a baseline of expected good practice, although potential for an increase in risk was also noted. Improved risk communication to consumers is recommended. SUMMARYFollowing a request from the European Food Safety Authority (EFSA), the EFSA Panel on Biological Hazards (BIOHAZ) was asked to deliver a scientific opinion on the public health risks related to the consumption of raw drinking milk (RDM). In particular, the BIOHAZ Panel was requested to identify the main microbiological hazards of public health significance that may occur in RDM from different animal species, to assess the public health risk arising from the consumption of RDM, to assess the likelihood of RDM being a significant source of antimicrobial resistant bacteria/resistance genes, to assess the additional risks associated with the sale of RDM through vending machines and via the internet and to identify and rank potential control options to reduce public health risks arising from consumption of RDM.According to European Union (EU) legislation, "raw milk" is defined as milk produced by the secretion of the mammary gland of farmed animals that has not been heated to more than 40 °C or undergone any treatment that has an e...

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Raw milk from vending machines: Effects of boiling, microwave treatment, and refrigeration on microbiological quality

Cited by 54 publications

References 21 publications

Homology-Based Modeling of Universal Stress Protein from Listeria innocua Up-Regulated under Acid Stress Conditions

Homology-Based Modeling of Universal Stress Protein from Listeria innocua Up-Regulated under Acid Stress Conditions

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

Scientific Opinion on the public health risks related to the consumption of raw drinking milk

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