A 100-Year Review: The production of fluid (market) milk

During the first 100 years of the Journal of Dairy Science, dairy foods and dairy production dairy scientists have partnered to publish new data and research results that have fostered the development of new knowledge. This knowledge has been the underpinning of both the commercial development of the fluid milk processing industry and regulations and marketing policies for the benefit of dairy farmers, processors, and consumers. During the first 50 years, most of the focus was on producing and delivering high-quality raw milk to factories and improving the shelf life of pasteurized fluid milk. During the second 50 years, raw milk quality was further improved through the use of milk quality payment incentives. Due to changing demographics and lifestyle, whole fluid milk consumption declined and processing technologies were developed to increase the range of fluid milk products (skim and low-fat milks, flavored milks, lactose-reduced milk, long-shelf-life milks, and milks with higher protein and calcium contents) offered to the consumer. In addition, technology to produce specialty high-protein sports beverages was developed, which expanded the milk-based beverage offerings to the consumer.     

Performance evaluation of small-batch container delivery systems used in lean manufacturing – Part 2: number of Kanban and workstation starvation

In lean manufacturing, milk run (MR) systems represent route-based, cyclic material handling systems that are used widely to enable frequent and consistent deliveries of containerised parts on an as-needed basis from a central storage area (the ‘supermarket’) to multiple line-side deposit points on the factory floor. In the first part of this two-part paper, a basic, single-tugger MR system is described, and stability conditions as well as the probability of exceeding either the physical capacity of the tugger or the prescribed cycle time are derived. Given the stability conditions, and the distribution of the number of containers requested per MR, in the second part of the paper, the number of Kanban required in the MR system is examined, and analytical approximations are derived both for the number of Kanban required and for predicting workstation starvation. The latter is a key concern when designing a MR system that will support workstations in a manufacturing plant. The performance of the analytic approximation is evaluated by simulating various MR systems. Our results suggest that, in a stable MR system, the number of Kanban and the physical capacity of the tugger have a bigger impact on workstation starvation than the prescribed cycle time.     

Characterization and Technological Properties of Lactic Acid Bacteria Isolated from Traditional Argentinean Goat’s Milk Products

A total of 286 lactic acid bacteria isolated from goat’s dairy products in northwest of Argentina were characterized. Lactobacilli (38%) and cocci (62%) were identified according to morphological, physiological, and relevant technological properties. L. plantarum (14%) and Enterococcus (34%) were the predominant species. S. thermophilus, Pediococcus and L. plantarum were the highest acid producers. Eight strains of L. fermentum produced bacteriocins or metabolites similar to bacteriocins. The API-ZYM test was applied to 39 isolates. Eight strains were selected from their both technological properties and enzymatic activities for use as starter or adjunct culture in the manufacture of artisanal goat cheeses.     

Impact of amorphous and crystalline lactose on milk chocolate properties

Chocolate mass of low viscosity is preferred for most applications. Milk powder influences processing behaviour, flow properties and taste of milk chocolate. The project aimed to investigate influences of skim milk powders containing amorphous or crystalline lactose on flow properties after producing samples by roller milling and conching or alternatively by ball milling. For the first case, it was found that mass consistency before roller milling is strongly influenced by lactose type; producers must specify it and adapt initial mass fat content. Little impact on final products was found after processing milk powders at equilibrium moisture. If predried powders are used for reducing conching time, crystalline lactose leads to chocolate with slightly lower viscosity. At ball mill processing, crystalline lactose resulted in significantly lower viscosity, for example 15% at 40 s^?1; thus, for this process, it can be recommended to use special milk powders high in crystalline lactose content.     

Organic whey as a source of Lactobacillus strains with selected technological and antimicrobial properties

Twenty‐five strains, isolated from raw, non‐pasteurised, organic whey samples, were identified phenotypically and genotypically. Biochemical tests were performed, and enzyme profiles, antibiotic resistance and antimicrobial properties were investigated. Sixteen strains were identified as genus Lactobacillus. Based on 16S rDNA gene sequence, the strains were identified as Lb. plantarum and Lb. fermentum. All of the strains had β‐galactosidase activity, and some of them reduced nitrate content. All strains utilised carbohydrates. The tested strains were characterised by low or average lipolytic and esterolytic activity. Moreover, the strains showed low proteolytic activity which is advantageous for their use as starter cultures for foods with low protein content. Strains Lb. fermentum S20, SM1, SM3, S2R and Lb. plantarum SM5 produced harmful N‐acetyl‐β‐glucosaminidase; moreover, the strain S20 produced also β‐glucuronidase. None of the strains produced α‐chymotrypsin. In phenotypic studies, most of the test strains were susceptible to gentamicin, ampicillin, tetracycline, chloramphenicol, penicillin and erythromycin. Strains Lb. plantarum S1 and Lb. fermentum S4, S7, S8, S10, SM1 and SM3 did not possess any transfer resistance genes. Antagonistic activity of the culture LAB strains was assessed as high or moderate in relation to the indicator strains, with the greatest zones of inhibition for E.coli and the smallest for L. monocytogenes ATCC 15313. This study reveals that the LAB strains isolated from organic whey have high potential for food application. Some strains of species Lb. fermentum (S4, S7, S8, S10) have been identified as the best candidates.     

Effect of replacing grass silage with red clover silage on nutrient digestion,nitrogen metabolism,and milk fat composition in lactating cows fed diets containing a 60:40 forage-to-concentrate ratio

Diets based on red clover silage (RCS) typically increase the concentration of polyunsaturated fatty acids (PUFA) in ruminant meat and milk and lower the efficiency of N utilization compared with grass silages (GS). Four multiparous Finnish Ayrshire cows (108 d postpartum) fitted with rumen cannulas were used in a 4 × 4 Latin square design with 21-d periods to evaluate the effect of incremental replacement of GS with RCS on milk production, nutrient digestion, whole-body N metabolism, and milk fatty acid composition. Treatments comprised total mixed rations offered ad libitum, containing 600 g of forage/kg of diet dry matter (DM), with RCS replacing GS in ratios of 0:100, 33:67, 67:33, and 100:0 on a DM basis. Intake of DM and milk yield tended to be higher when RCS and GS were offered as a mixture than when fed alone. Forage species had no influence on the concentration or secretion of total milk fat, whereas replacing GS with RCS tended to decrease milk protein concentration and yield. Substitution of GS with RCS decreased linearly whole-tract apparent organic matter, fiber, and N digestion. Forage species had no effect on total nonammonia N at the omasum, whereas the flow of most AA at the omasum was higher for diets based on a mixture of forages. Replacing GS with RCS progressively lowered protein degradation in the rumen, increased linearly ruminal escape of dietary protein, and decreased linearly microbial protein synthesis. Incremental inclusion of RCS in the diet tended to lower whole-body N balance, increased linearly the proportion of dietary N excreted in feces and urine, and decreased linearly the utilization of dietary N for milk protein synthesis. Furthermore, replacing GS with RCS decreased linearly milk fat 4:0 to 8:0, 14:0, and 16:0 concentrations and increased linearly 18:2n-6 and 18:3n-3 concentrations, in the absence of changes in cis-9 18:1, cis-9, trans-11 18:2, or total trans fatty acid concentration. Inclusion of RCS in the diet progressively increased the apparent transfer of 18-carbon PUFA from the diet into milk, but had no effect on the amount of 18:2n-6 or 18:3n-3 at the omasum recovered in milk. In conclusion, forage species modified ruminal N metabolism, the flow of AA at the omasum, and whole-body N partitioning. A lower efficiency of N utilization for milk protein synthesis with RCS relative to GS was associated with decreased availability of AA for absorption, with some evidence of an imbalance in the supply of AA relative to requirements. Higher enrichment of PUFA in milk for diets based on RCS was related to an increased supply for absorption, with no indication that forage species substantially altered PUFA bioavailability.     

MALDI Q-TOF CID MS for Diagnostic Ion Screening of Human Milk Oligosaccharide Samples

Human milk oligosaccharides (HMO) represent the bioactive components of human milk, influencing the infant’s gastrointestinal microflora and immune system. Structurally, they represent a highly complex class of analyte, where the main core oligosaccharide structures are built from galactose and N-acetylglucosamine, linked by 1–3 or 1–4 glycosidic linkages and potentially modified with fucose and sialic acid residues. The core structures can be linear or branched. Additional structural complexity in samples can be induced by endogenous exoglycosidase activity or chemical procedures during the sample preparation. Here, we show that using matrix-assisted laser desorption/ionization (MALDI) quadrupole-time-of-flight (Q-TOF) collision-induced dissociation (CID) as a fast screening method, diagnostic structural information about single oligosaccharide components present in a complex mixture can be obtained. According to sequencing data on 14 out of 22 parent ions detected in a single high molecular weight oligosaccharide chromatographic fraction, 20 different oligosaccharide structure types, corresponding to over 30 isomeric oligosaccharide structures and over 100 possible HMO isomers when biosynthetic linkage variations were taken into account, were postulated. For MS/MS data analysis, we used the de novo sequencing approach using diagnostic ion analysis on reduced oligosaccharides by following known biosynthetic rules. Using this approach, de novo characterization has been achieved also for the structures, which could not have been predicted.     

Seasonal variation of aflatoxin M1 in raw milk from the Yangtze River Delta region of China

The objective of this study was to evaluate the occurrence of aflatoxin M₁ (AFM₁) in raw milk samples from 18 dairy farms in the Yangtze River Delta region during four different seasons. A total of 72 tank milk samples was collected with 18 samples for each season. Milk AFM₁ was detected using LC-MS/MS. The AFM₁ was detected in 43 milk samples (59.7%) ranging in concentration from 10 to 420 ng/L. The concentration of AFM₁ in raw milk was significantly higher during the winter (123 ng/L) than during other seasons (P < 0.05). There was no significant difference between the spring (29.1 ng/L), summer (31.9 ng/L), and autumn (31.6 ng/L) (P > 0.05) seasons. This indicates that raw milk collected during the winter is at high risk for AFM₁ and that seasonal factors should be considered for the management of aflatoxins in both the feed and milk.     

Identification and antibiotic resistance of Lactobacilli isolated from raw cow’s milk of Oujda City (Morocco)

In this study, a Lactobacillus strain was isolated from raw cow milk. It was tentatively identified at the species level according to its carbohydrate fermentation profile and phenotype characteristics as Lactobacillus paracasei KSNM. The susceptibility of the identified Lactobacillus to 23 antibiotics was performed using the disc diffusion testing method. Inhibition zone diameters were measured and expressed in terms of sensitive, intermediate or resistant. KSNM strain was sensitive toward; amoxicillin, ampicillin, amoxyclav (amoxicillin + clavulanic acid), tetracycline, macrolides, sulfamides/trimethoprim, and rifampicin. But, it expressed intermediate sensitivity toward; cefamandole, cefaclor, and cephalothin. However, it was resistant to penicillin G, aminoglycosides, quinolones, ciprofloxacin, lincomycin, nitroxolin, and a large number of cephalosporins, which included cefoxitin, cefotaxime, and ceftriaxone.