Dairy Ecosystems Research Articles

The interrelationship between Lean 4.0 and value co-creation: an empirical study in the dairy sector

PurposeThis study aims to examine the impact of Lean 4.0 practices on value co-creation in the dairy ecosystem.Design/methodology/approachData collection were carried out through a questionary application with 126 professionals linked to the dairy ecosystem, including milk producers, milk cooperatives and milk transporters. The data were analyzed using Cluster Analysis, Mann-Whitney test and Chi-Square test.FindingsA strong relation was found between the use of Lean 4.0 tools and the increase in operational performance, in addition to milk quality. Moreover, it can be noted that the use of digital technologies from Industry 4.0 has a strong relation with dairy production optimization, in other words, it is possible to be more efficient in the dairy process via Lean 4.0 adoption.Research limitations/implicationsThe study is limited to analyzing the Brazilian dairy ecosystem. The results presented may not reflect the characteristics of the other countries.Practical implicationsOnce the potential empirical impacts of the relation between Lean 4.0 and value co-creation are elucidated, it is possible to direct strategies for decision-making and guide efforts by researchers and professionals to deal with the waste mitigation present in the dairy sector.Social implicationsLean 4.0 proves to be a potential solution to improve the operational performance of the dairy production system. Lean 4.0, linked to value co-creation, allows the integration of the production sector with consumers, through smart technologies, so new services and experiences can be provided to the consumer market. Additionally, the consumer experience can be stimulated based on Lean 4.0, once the quality specification is highlighted based on data science and smart management control.Originality/valueTo the best of the authors’ knowledge, this is the first study that analyzes the interrelationship between the Lean 4.0 philosophy and the value co-creation in the dairy ecosystem. In this sense, the study reveals the main contributions of this interrelation to the dairy sector via value co-creation, which demonstrates a new perspective on the complementarity of resources, elimination of process losses and new experiences for the user through digital technologies integrated with the Lean Thinking approach.

Precise Populations’ Description in Dairy Ecosystems Using Digital Droplet PCR: The Case of L. lactis Group in Starters

Lactococcus lactis group (composed of the lactis and cremoris subspecies, recently reassigned as two distinct species) plays a major role in dairy fermentations. Usually present in starter cultures, the two species enable efficient acidification and improve the organoleptic qualities of the final product. Biovar diacetylactis strains produce diacetyl and acetoin, aromas from the citrate metabolization. As these populations have distinct genomic and phenotypic characteristics, the proportions of each other will affect the final product. Today, there is no quantitative test able to distinguish between the two species and the biovar in dairy ecosystems. In this study, we developed a specific, reliable, and accurate strategy to quantify these populations using, species-, and diacetylactis-specific fluorescent probes in digital droplet PCR assays (ddPCR). Species were distinguished based on three single nucleotide polymorphisms in the glutamate decarboxylase gadB gene, and the citD gene involved in citrate metabolism was used to target the biovar. Used in duplex or singleplex, these probes made it possible to measure the proportion of each population. At 59°C, the probes showed target specificity and responded negatively to the non-target species usually found in dairy environments. Depending on the probe, limit of detection values in milk matrix ranged from 3.6 × 103 to 1.8 × 104 copies/ml. The test was applied to quantify sub-populations in the L. lactis group during milk fermentation with a commercial starter. The effect of temperature and pH on the balance of the different populations was pointed out. At the initial state, lactis and cremoris species represent, respectively, 75% and 28% of the total L. lactis group and biovar diacetylactis strains represent 21% of the lactis species strains. These ratios varied as a function of temperature (22°C or 35°C) and acidity (pH 4.5 or 4.3) with cremoris species promoted at 22°C and pH4.5 compared to at 35°C. The biovar diacetylactis strains were less sensitive to acid stress at 35°C. This methodology proved to be useful for quantifying lactis and cremoris species and biovar diacetylactis, and could complete 16S metagenomics studies for the deeply description of L. lactis group in complex ecosystems.

Antilisterial and antistaphylococcal activity of a Lactococcus lactis strain isolated from Brazilian fresh Minas cheese

Abstract Lactococcus lactis QMF 11, isolated from Brazilian fresh cheese, produces bacteriocin like inhibitory substances (bac+). To evaluate L. lactis QMF11 possible application on biopreservation systems of dairy food, co‐inoculation studies were performed in pasteurized milk (8 °C, 10 days) targeting the inhibition of Listeria monocytogenes ATCC 7644 or Staphylococcus aureus ATCC 25923. Lactobacillus sakei ATCC 15521 was used as a negative control for bacteriocin production (bac−). L. monocytogenes and S. aureus reached 8 log CFU ml−1 and 5.4 log CFU ml−1 in monoculture, respectively, compared to <2.3 log CFU ml−1 and 4.7 log CFU ml−1 in co‐culture with L. lactis QMF 11. Instead, in the presence of the bac−, L. monocytogenes population reached 7.3 log CFU ml−1 and S. aureus populations 5.5 log CFU ml−1. These results indicate that L. lactis QMF11 may have potential for be use as biopreservative culture in dairy products, mainly because of its antilisterial activity.Practical applicationsThere is a renewed interest in the use protective bacterial cultures or their metabolites to guarantee the microbiological safety and to extend the shelf life of dairy products, in a process called biopreservation. The research in this area has been leveraged by consumers demand for naturally preserved foods. Dairy products are natural niches for Lactococcus lactis strains, and these bacteria have been associated with food production and preservation since ancient times. As a dominant species in dairy ecosystems, L. lactis strains are very interesting because they are not likely to require regulatory approval for practical application as bioprotective cultures.

Survey on the phage resistance mechanisms displayed by a dairy Lactobacillus helveticus strain

In this study the presence and functionality of phage defence mechanisms in Lactobacillus helveticus ATCC 10386, a strain of dairy origin which is sensitive to ΦLh56, were investigated. After exposure of ATCC 10386 to ΦLh56, the whole-genome sequences of ATCC 10386 and of a phage-resistant derivative (LhM3) were compared. LhM3 showed deletions in the S-layer protein and a higher expression of the genes involved in the restriction/modification (R/M) system. Genetic data were substantiated by measurements of bacteriophage adsorption rates, efficiency of plaquing, cell wall protein size and by gene expression analysis. In LhM3 two phage resistance mechanisms, the inhibition of phage adsorption and the upregulation of Type I R/M genes, take place and explain its resistance to ΦLh56. Although present in both ATCC 10386 and LhM3 genomes, the CRISPR machinery did not seem to play a role in the phage resistance of LhM3. Overall, the natural selection of phage resistant strains resulted successful in detecting variants carrying multiple phage defence mechanisms in L. helveticus. The concurrent presence of multiple phage-resistance systems should provide starter strains with increased fitness and robustness in dairy ecosystems.

Specific populations of the yeast Geotrichum candidum revealed by molecular typing.

Geotrichum candidum is a ubiquitous yeast and an essential component in the production of many soft cheeses. We developed a multilocus sequence typing (MLST) scheme with five retained loci (NUP116, URA1, URA3, SAPT4 and PLB3) which were sufficiently divergent to distinguish 40 sequence types (STs) among the 67 G. candidum strains tested. Phylogenetic analyses defined five main clades; one clade was restricted to environmental isolates, three other clades included distinct environmental isolates and dairy strains, while the fifth clade comprised 34 strains (13 STs), among which all but two were isolated from milk, cheese or the dairy environment. These findings suggest an adaptation to the dairy ecosystems by a group of specialized European G. candidum strains. In addition, we developed a polymerase chain reaction inter-long terminal repeat scheme, a fast and reproducible random amplification of polymorphic DNA-like method for G. candidum, to type the closely related dairy strains, which could not be distinguished by MLST. Overall, our findings distinguished two types of dairy strains, one forming a homogeneous group with little genetic diversity, and the other more closely related to environmental isolates. Neither regional nor cheese specificity was observed in the dairy G. candidum strains analysed. This present study sheds light on the genetic diversity of both dairy and environmental strains of G. candidum and thus extends previous characterizations that have focused on the cheese isolates of this species. Copyright © 2016 John Wiley & Sons, Ltd.

Technological, phenotypic and genotypic characterization of lactobacilli from Graviera Kritis PDO Greek cheese, manufactured at two traditional dairies

The phenotypic and genotypic variability of 54 lactobacilli isolated from mature Graviera Kritis cheese made at two dairies, was investigated. Classical biochemical tests, SDS-PAGE and 16S rRNA gene sequencing used for species assignation, showed that Lb. brevis and Lb. paracasei were the predominant species. RAPD-PCR and PFGE analysis of the 48 isolates of predominant species distinguished 21 genotype fingerprints, revealing a high genotypic heterogeneity. The examination of the technological properties of lactobacilli showed a significant (P<0.05) variation, in respect of their acidification and proteolytic activity. Genotypic clustering of lactobacilli and Principal Component Analysis (PCA) of their technological properties indicated that lactobacilli are associated with their particular production dairy ecosystem. Overall, polyphasic characterization of lactobacilli isolated from mature cheese, based on genotypic and phenotypic data, provides solid basis for understanding their distribution and their functional significance and may be used as a tool to select strains appropriate as adjuncts cultures.

Culture and Molecular Detection of Staphylococcus aureus in Dairy Products of Ahwaz

Staphylococcus aureus is one of the most important bacteria that cause food poisoning and disease in humans and herds. Milk and milk products are important part of the human diet also support the growth of pathogenic organisms. The present study was aimed to determine the prevalence of coagulase positive Staphylococcus aureus in different kinds of dairy products of Ahvaz Province.460 dairy product samples randomly were collected from Ahvaz Province. The samples were analyzed for the presence of S. aureus. Positive samples screened by microbiological tests.DNA extracted from all isolates and the PCR carried out using specific primers for S. aureus. The results indicated that 127 (27.61%) of dairy samples were contaminated by Staphylococcus aureus (curd 24.5%, dough 19%, butter and cream 14.5%, yogurt 12.5%, cheese10%, milk 5%).High prevalence of Staphylococcus aureus contamination in milk and milk products of Ahvaz suggests that more control measures should be applied during dairy production. The obtained results are useful for designing strategic plans of prevention and control program against Staph. aureus in dairy ecosystem.

Updating on the fungal composition in Sardinian sheep's milk by culture-independent methods

This work applies culture-independent methods for the characterization of fungal populations (yeasts and moulds) naturally occurring in Sardinian ewe's milk sampled in the Italian areas with the largest dairy production (Sardinia and Lazio regions). Sequences of the D1/D2 variable domains at the 5' end of the 26S rRNA gene were obtained by amplification of DNA directly isolated from milk, and this allowed identification of a total of 6 genera and 15 species of fungi. Among the 6 identified genera Geotrichum spp., Candida spp., Phaeosphaeriopsis spp., Pestalotiopsis spp. and Cladosporium spp. belong to the phylum of Ascomycota, while Cryptococcus spp. is part of the phylum of Basidiomycota. In particular, two genera (Pestalotiopsis and Phaeosphaeriopsis) and two species (Plectosphaerella cucumerina and Pryceomyces carsonii) have never been reported in dairy ecosystems before. Results provide evidence that several moulds and yeasts, previously described only in ovine cheeses, are transferred directly from raw milk. The knowledge of fungal consortia inhabiting sheep raw milk is a particularly relevant issue because several species are directly involved in cheese making and ripening, determining the typical aroma. On the other hand, spoilage yeasts and moulds are involved in anomalous fermentation of cheese and may be responsible for considerable economic losses and serious risks for consumers' health.

The Microfloras and Sensory Profiles of Selected Protected Designation of Origin Italian Cheeses.

Approximately 39 Italian cheeses carry protected designation of origin (PDO) status. These cheeses differ in their manufacturing technology and the microbial flora which comprise the finished products. The evolution of lactic microflora in cheeses with PDO status is of particular interest because the biochemical activities of these organisms participate in cheesemaking and may play an acknowledged role in the development of organoleptic characteristics during ripening. Nonstarter lactic acid bacteria (NSLAB) constitute complex microbial associations that are characterized by the occurrence of various species and many biotypes as a result of a number of selective conditions persisting during the manufacturing process and different ecological niches. The evolution of different species during ripening of Fiore Sardo showed that, when present, Lactobacillus paracasei persists and dominates the microflora of the cheese in the last period of ripening, suggesting that this species, more resistant to the constraints of the mature cheese, could be involved in proteolysis and in other enzymatic processes occurring during cheese ripening. In contrast, the stretching step typical of pasta filata cheese, such as Ragusano, induced a simplification of the raw milk profiles, allowing the persistence only of some predominant species, such as Streptococcus thermophilus, Lactobacillus delbrueckii subsp. lactis, Lactococcus lactis, and Streptococcus macedonicus, after the stretching step. Lactobacillus plantarum and L. paracasei were isolated from ripened Castelmagno PDO cheese samples with the highest frequencies. These species, generally absent in the milk, occur in dairy ecosystems and dominate the bacterial flora of many ripened semihard cheeses. In PDO long-ripened Italian cheese such as Parmigiano Reggiano, the NSLAB population is mainly formed by L. paracasei, Lactobacillus rhamnosus, and Pediococcus acidilactici. Lactobacillus helveticus, L. delbrueckii subsp. lactis, and L. delbrueckii subsp. bulgaricus were also detected. Continued insight into the microbial populations of traditional Italian cheeses will allow continued production of characteristic, high-quality cheeses which have been enjoyed for many centuries.

Diversity of Streptococcus thermophilus in bacteriocin production; inhibitory spectrum and occurrence of thermophilin genes

The bacteriocin-producing Streptococcus thermophilus strains that can dominate in natural dairy ecosystems, may also enhance safety in products obtained from natural cultures. In this study, we sought to identify bacteriocin production and bacteriocin genes in 75 strains of dairy and plant origin. The strains were tested for antimicrobial activity against pathogens or pathogen models, spoiling bacteria, and lactic acid bacteria associated with dairy products. All strains moderately inhibited Staphylococcus aureus P310, none inhibited Listeria innocua LMG 11387T or Clostridium tyrobutyricum LMG 1285T. In addition, 14 were active against one or more indicators in addition to S. aureus P310. Inhibition of other starter bacteria was more common than the inhibition of unwanted microorganisms. The involvement of a proteinaceous compound was ascertained in all cases. Results suggested that the selection of bacteriocinogenic S. thermophilus strains for use in biopreservation must take into account the effects exerted on other lactic acid bacteria.PCR detection of thermophilin genes proved unreliable in predicting antimicrobial activity. For S. thermophilus PRI36 and PRI45, with relevant inhibitory features, the identity of the bacteriocin genes present in the thermophilin 9 cluster was defined, thus revealing novel variants for this genome region.

Identification of Microbiota Present on the Surface of Taleggio Cheese Using PCR–DGGE and RAPD–PCR

Microbial DNA from 9 batches of Taleggio PDO cheese sampled at various times during ripening, brines, swabs of wooden shelves used for cheese dry-salting, and 13 commercial cheeses were analyzed by denaturing gradient gel electrophoresis (PCR-DGGE) and/or random amplification of polymorphic DNA (RAPD-PCR). Sequencing allowed the detection of 12 genera, 27 species, and 2 unclassified bacteria. Molecular analysis allowed for the detection of microorganisms not previously associated with Taleggio such as Lactobacillus paracasei, Carnobacterium maltaromaticum, Bacillus licheniformis, Corynebacterium variabile, Psychrobacter cibarius, and Staphylococcus carnosus. For the first time Massilia spp. was detected in a dairy ecosystem. Indigenous species and strains of bacteria identified by this study could be used for the selection of dairy cultures to be employed routinely by manufacturers to control the Taleggio cheese production. The new cultures may give the bases for driving dairy processes and, consequently, control the typical flavor resulting from metabolic actions of environmental microorganisms.

Identification of dairy lactic acid bacteria by tRNAAla–23S rDNA-RFLP

The aim of this study was to evaluate the potential of target tRNAAla–23S ribosomal DNA for identification of lactic acid bacteria strains associated with dairy ecosystem. For this purpose tRNAAla–23S ribosomal DNA Restriction Fragment Length Polymorphism (tRNAAla–23S rDNA-RFLP) was compared with two widely used DNA fingerprinting methods – P1 Random Amplified Polymorphic DNA (RAPD), (GTG)5 repetitive extragenic palindromic PCR (rep-PCR) – for their ability to identify different species on a set of 10 type and 34 reference strains.Moreover, 75 unknown isolates collected during different stages of Grana Padano cheese production and ripening were identified using tRNAAla–23S rDNA-RFLP and compared to the RFLP profiles of the strains in the reference database. This study demonstrated that the target tRNAAla–23S rDNA has high potential in bacterial identification and tRNAAla–23S rDNA-RFLP is a promising method for reliable species-level identification of lactic acid bacteria (LAB) in dairy products.

Ribotyping of Streptococcus uberis from a dairy's environment, bovine feces and milk

Streptococcus uberis is a major cause of bovine mastitis and infections commonly result from environmental exposure to the pathogen. To identify specific sources of mastitis-causing S. uberis strains, samples were collected monthly from the environment and feces of dry cows in a grazing herd. Environmental and fecal strains of S. uberis were compared to those found in milk. S. uberis was detected in 63% of 94 environmental samples, including water, soil, plant matter, bedding material, flies, and hay, in 23% of 107 fecal samples, and in 4% of 787 milk samples. Automated PvuII ribotyping revealed 48 ribotypes among 266 isolates. Per sample, up to five ribotypes were detected. The distribution of ribotypes did not differ significantly among environmental, fecal and milk samples. Specific environmental sources or strains of udder-pathogenic S. uberis were not identified. Fecal shedding was not persistent and did not differ between dry-off and calving. The proportion of fecal samples containing S. uberis was highest during the summer grazing season. S. uberis was common in farm soil (31 of 35 samples) but not in non-farm soil (0 of 11 samples). We hypothesize that fecal shedding of S. uberis may play a role in maintenance of S. uberis populations in the dairy ecosystem.

Molecular fingerprinting of dairy microbial ecosystems by use of temporal temperature and denaturing gradient gel electrophoresis.

Numerous microorganisms, including bacteria, yeasts, and molds, constitute the complex ecosystem present in milk and fermented dairy products. Our aim was to describe the bacterial ecosystem of various cheeses that differ by production technology and therefore by their bacterial content. For this purpose, we developed a rapid, semisystematic approach based on genetic profiling by temporal temperature gradient electrophoresis (TTGE) for bacteria with low-G+C-content genomes and denaturing gradient gel electrophoresis (DGGE) for those with medium- and high-G+C-content genomes. Bacteria in the unknown ecosystems were assigned an identity by comparison with a comprehensive bacterial reference database of approximately 150 species that included useful dairy microorganisms (lactic acid bacteria), spoilage bacteria (e.g., Pseudomonas and Enterobacteriaceae), and pathogenic bacteria (e.g., Listeria monocytogenes and Staphylococcus aureus). Our analyses provide a high resolution of bacteria comprising the ecosystems of different commercial cheeses and identify species that could not be discerned by conventional methods; at least two species, belonging to the Halomonas and Pseudoalteromonas genera, are identified for the first time in a dairy ecosystem. Our analyses also reveal a surprising difference in ecosystems of the cheese surface versus those of the interior; the aerobic surface bacteria are generally G+C rich and represent diverse species, while the cheese interior comprises fewer species that are generally low in G+C content. TTGE and DGGE have proven here to be powerful methods to rapidly identify a broad range of bacterial species within dairy products.

Evaluation of bacterial communities belonging to natural whey starters for Grana Padano cheese by length heterogeneity-PCR.

To detect bacteria present in controlled dairy ecosystems with defined composition by length-heterogeneity (LH)-PCR. LH-PCR allows to distinguish different organisms on the basis of natural variations in the length of 16S rRNA gene sequences. LH-PCR was applied to depict population structure of the lactic acid bacteria (LAB) species recoverable from Grana Padano cheese whey starters. Typical bacterial species present in the LAB community were evidenced and well discriminated. Small differences in species composition, e.g. the frequent finding of Streptococcus thermophilus and the constant presence of thermophilic lactobacilli (Lactobacillus helveticus, Lact. delbrueckii subsp. lactis/bulgaricus and Lact. fermentum) were reliably highlighted. Specificity of LH-PCR was confirmed by species-specific PCR from total DNA of the cultures. LH-PCR is a useful tool to monitor microbial composition and population dynamics in dairy starter cultures. When present, non-dominant bacterial species present in the whey starters, such as Strep. thermophilus, can easily be visualized and characterized without isolating and cultivating single strains. A similar approach can be applied to more complex dairy ecosystems such as milk or cheese curd. Community members and differences in population structure of controlled dairy ecosystems such as whey starters for hard cheeses can be evaluated and compared in a relative easy, fast, reliable and highly reproducible way.

Molecular diversity within Lactobacillus helveticus as revealed by genotypic characterization.

Lactobacillus helveticus is a homofermentative thermophilic lactic acid bacterium that is used in the manufacture of Swiss type and long-ripened Italian cheeses, such as Emmental, Grana, and Provolone cheeses. Substantial differences in several technologically important characteristics are found among L. helveticus strains isolated from natural dairy starter cultures. In the present study we investigated the genotypic diversity of 74 strains isolated from different dairy cultures used for manufacturing Grana and Provolone cheeses and six collection strains. A restriction fragment length polymorphism analysis of both total genomic DNA and the 16S rRNA gene (ribotyping) was used as genotypic fingerprinting. A multivariate statistical analysis of the data enabled us to identify significant genotypic heterogeneity in L. helveticus. We found that genotypic fingerprinting could be used to distinguish strains; in particular, it was possible to associate the presence of specific strain genotypes with dairy ecosystem sources (e.g., Grana or Provolone cheese). Our data contribute to the description of microbial heterogeneity in L. helveticus and provide a more solid basis for understanding the functional and ecological significance of the presence of different L. helveticus biotypes in natural dairy starter cultures.

Deposition of Fallout Cesium 137 on Forage and Transfer to Milk

ESIUM 137 is one of the most important contaminants from fallout nuclear debris because of its long physical half-life and affinity for biological systems. Body burdens of this radionuclide in man result principally from the food-chain sequence: air and precipitation to plants, plants to milk and meat, with dairy and beef cattle as the principal vectors between plants and man's diet. This apparently simple relation describes the food-chain pattern for cesium 137 quite adequately since uptake of cesium 137 by plants from soil is negligible (1) and dairy products and beef contribute most of the cesium 137 in the average U.S. diet (2). Mathematical models describing the transport of radioactive fa,llout to milk, emphasizing strontium 90, have been presented (3-7). In these models, certain common assumptions were made regarding forage contamination and feeding practices, but actual data were unavailable. The relation between radionuclide levels of forage and milk has been reported by several workers for strontium 90 (8-12) and cesium 137 (13,14). The general relation between fallout, feeding practices, and milk levels has been discussed (15-18). A common deficiency of these models and discussions has been the absence of concomitant data for all three: fallout, feed, and milk. As pointed out in a recent panel discussion of approaches to studying radiological hazards in the environment, the large-scale monitoring network method and t,he investigation of specific ecosystems are complementary in understanding the behavior of fission products in the biosphere (19). Observations on the transport of cesium 137 in a controlled dairy ecosystem at Colorado State University were initiated in 1962, and data have been collected for the va.rious steps in the food chain. The ecotsystem consisted of one herd of 112 cows and an irrigated farm in a geographic region that would be classified as a dry area (20). From the study of this ecosystem, we believe that estimates of ceisium 137 body burdens of the general population can be significantly improved.