Hasil untuk "Dairy processing. Dairy products"

A. K. Anal, Harjinder Singh

O. Odeyemi, O. Alegbeleye, M. Strateva et al.

The increasing global population has resulted in increased demand for food. Goods quality and safe food is required for healthy living. However, food spoilage has resulted in food insecurity in different regions of the world. Spoilage of food occurs when the quality of food deteriorates from its original organoleptic properties observed at the time of processing. Food spoilage results in huge economic losses to both producers (farmers) and consumers. Factors such as storage temperature, pH, water availability, presence of spoilage microorganisms including bacteria and fungi, initial microbial load (total viable count-TVC), and processing influence the rate of food spoilage. This article reviews the spoilage microbiota and spoilage mechanisms in meat and dairy products and seafood. Understanding food spoilage mechanisms will assist in the development of robust technologies for the prevention of food spoilage and waste.

P. Vos, M. Faas, M. Spasojevic et al.

L. Sarao, M. Arora

P. Walstra, T. Geurts, A. Noomen et al.

Lochan Singh, J. G. Varshney, Tripti Agarwal

C. Monteiro

Bozhao Li, Thomas C. France, James A. O'Mahony et al.

ABSTRACT: The rennet and acid coagulation properties of reconstituted micellar casein concentrate prepared using cold or warm microfiltration (MF), at similar casein contents, were investigated, with low-heat skim milk powder (LHSMP) as a control. The MF retentates had higher casein content (as % of total protein) compared with LHSMP, and heat-induced whey protein-casein aggregates were only present in LHSMP. All MF retentates showed shorter rennet coagulation times and higher gel strengths than LHSMP, which may be linked to lower levels of whey protein (either native or denatured). At similar casein contents, longer rennet coagulation times were evident for cold MF retentates compared with warm MF retentates, as the ratio of κ-CN as a function of total increased with the depletion of β-CN. In terms of acid-induced coagulation, all MF retentates coagulated at a pH >5, higher than the gelation pH of LHSMP (4.7–4.9), which was confirmed by microscopic and textural analysis. An inflection point (increase, followed by a decrease) in the storage modulus value was seen during the acidification of warm MF retentates, but not cold MF retentates; this may be related to structural rearrangements of the gel initiated by release of colloidal calcium phosphate and compacting of the structure of warm MF retentate gels as pH decreased. Both warm and cold MF retentates exhibited shorter rennet coagulation times, stronger rennet-induced gels and higher acid-induced gelation pH compared with LHSMP, which might influence their use for the manufacture of cheese or yogurt with tailored functionalities.

W.A. Smith, K. Ishida, J.W. Darrah et al.

ABSTRACT: We measured the effect of physically effective NDF (peNDF) in diets containing lower or higher concentrations of undegraded NDF at 240 h of in vitro fermentation (uNDF240) on DMI, milk production and composition, chewing behavior, ruminal responses, and nutrient digestibility. Sixteen Holstein cows (8 ruminally cannulated) averaging 123 ± 9 (SD) DIM were used in a replicated 4 × 4 Latin square design with 4-wk periods. Cows were fed TMR that differed in uNDF240 and peNDF content primarily by changing forage-to-concentrate ratio and particle size of timothy hay. Treatments were arranged as a 2 × 2 factorial arrangement consisting of (1) lower uNDF240 (LU; 8.9% of TMR DM) or higher uNDF240 (HU; 11.4% of TMR DM) and (2) lower peNDF (LP; 18.6%–20.1% of TMR DM) or higher peNDF (HP; 21.8%–22.0% of TMR DM). Physically effective uNDF240 (peuNDF240) was calculated as the product of the dietary physical effectiveness factor (pef; % of TMR DM retained on a ≥1.18-mm sieve with vertical dry sieving) and uNDF240 (as a percentage of DM) with the purpose of combining particle size and undegradability of fiber into one measure. Dietary peuNDF240 concentrations were 5.4% (LU-LP), 5.8% (LU-HP), 5.9% (HU-LP), and 7.1% (HU-HP) of TMR DM. Cows were housed in individual tiestalls, fed TMR once daily, and milked 3×/d. Data were analyzed as a factorial arrangement of treatments within a replicated Latin square design using the MIXED procedure of SAS (ver. 9.4; SAS Institute Inc., Cary, NC). The model included the fixed effects of uNDF240, peNDF, uNDF240 × peNDF, period within replicated square, and square. Cow within square was a random effect. There was an interaction between dietary peNDF and uNDF240, with cows fed the HU-HP diet consuming 10% less DM (24.9 kg/d) than cows fed the HU-LP (27.4 kg/d) or either LU diet (27.4 kg/d). Diets higher in peNDF content elicited greater peNDF intake. However, there was an interaction between uNDF240 and peNDF for uNDF240 intake driven by the HU-LP diet (3.1 kg/d) compared with the HU-HP (2.9 kg/d) and LU diets (2.4 kg/d). Intake of peuNDF240 reflected dietary pef and uNDF240 content, as expected. There was an effect of uNDF240 and peNDF on ECM production, and it tracked with dietary peuNDF240 (47.5, 45.2, 46.5, and 44.1 kg/d for diets LU-LP, LU-HP, HU-LP, and HU-HP, respectively). Mean ruminal pH increased, total VFA concentration (millimolar) decreased, and acetate-to-propionate ratio increased with higher dietary uNDF240, but peNDF content had no effect. Rumination time (min/d) was unaffected by diet, although eating time (min/d) was increased by both uNDF240 and peNDF content. An interaction between uNDF240 and peNDF resulted in lower dietary peNDF reducing eating and rumination time (min/kg of DMI) primarily for the HU diets. The HU diets increased the ruminal pool size of NDF and uNDF240 versus the LU diets, slowed NDF ruminal turnover rate, and increased apparent total-tract digestibility of potentially degradable NDF (NDF − uNDF240). Responses in DMI, ECM, chewing behavior, and ruminal characteristics reflected dietary particle size and fiber undegradability as measured by dietary uNDF240, peNDF, and peuNDF240 content.

Jingjing Jia, Xin-Ying Gao, M. Hao et al.

Francesca Mercogliano, Corinne Bani, Marco Tretola et al.

The European Circular Economy Action Plan outlines a forward-looking strategy that emphasizes waste reduction and the acquisition of high-quality secondary resources. Previous research has shown that cocoa processing by-products contain compounds of interest for various industrial areas, making them an attractive matrix for reuse. However, a gap remains in our understanding of the safety of these by-products intended for feed. In this study, theobromine and caffeine were quantified by High-Performance Liquid Chromatography (HPLC-UV) in cocoa hulls for safety considerations, evaluating theobromine compliance with toxicological and safety levels, and considering their potential application as an ingredient in animal feed. In addition, the identification of phenolic components and associated antioxidant activity was conducted through High-Performance Thin-Layer Chromatography (HPTLC). This preliminary study indicates that theobromine content is a limiting factor for the inclusion of cocoa hulls in animal diets, as it restricts inclusion levels to remain within current regulatory limits. Examples of general estimates of dietary theobromine exposure at inclusion levels based on regulatory limits for dairy cows and veal calves confirmed a low risk for animal health. Furthermore, the detection of antioxidant activity linked to the presence of polyphenols highlights the potential of cocoa hulls as a sustainable food by-product for feed formulation.

Renata Žvirdauskienė, Vesta Jonikė, Loreta Bašinskienė et al.

Fermenting fruit and vegetable juices with probiotic bacteria is becoming a popular way to create functional drinks, offering an alternative to traditional dairy-based probiotic products. These plant-based juices are naturally rich in nutrients that help support the growth and activity of various probiotic strains. They also meet the rising demand for lactose-free, vegan, and clean-label options. This review looks at the key microbiological, nutritional, and sensory aspects of probiotic fermentation in juice. Common probiotic groups like <i>Lactobacillus</i>, <i>Bifidobacterium</i>, <i>Lactococcus</i>, <i>Bacillus</i>, and <i>Streptococcus</i> show different abilities to adapt to juice environments, affecting properties such as antioxidant levels, shelf life, and taste. The review also explores how factors like pH, sugar levels, heating, and storage can influence fermentation results. New non-thermal processing methods that help maintain probiotic survival are also discussed. Since fermented juices can sometimes develop off-flavors, this paper looks at ways to improve their taste and overall consumer appeal. Finally, future directions are suggested, including personalized nutrition, synbiotic products, and advanced encapsulation technologies. Overall, probiotic fermentation of fruit and vegetable juices shows strong potential for developing a new generation of healthy and appealing functional foods.

L. Chen, V.M. Thorup, S. Østergaard

ABSTRACT: Given global warming and the growing dairy cow population, heat stress in dairy herds is of increasing concern. During heat stress, dairy cows suffer from compromised productivity and animal welfare in terms of reduced feed intake and milk production, decreased reproductive performance, and generally increased risk of health problems. These effects and their interactions are complex and are usually quantified separately; thus, a comprehensive understanding of the herd-level performance is missing. Moreover, compromised animal welfare and productivity may impact enteric methane (CH4) emission; however, these effects have rarely been investigated. Therefore, by performing herd simulation, this study aimed to model the impact of heat stress on dairy production and enteric CH4 emissions by aggregating its effects on milk production, reproduction, and health. Specifically, 10 scenarios (including baseline) were simulated in a conventional, high-yielding Danish herd by incorporating different combinations of effects on milk production, reproduction, and health of heat stress in different exposure durations (1, 2, and 4 mo). Sensitivity analyses were further conducted to account for the effects of different reduction rates in feed efficiency (kg ECM/kg DMI). Results showed that heat stress decreased the herd-level milk yield by up to 8.6% if all effects were combined in a duration of 4 mo, whereas a direct effect on milk yield only decreased herd-level yield by up to 6.9%. Heat stress increased the herd-level enteric CH4 intensity ranging from 0.8% to 6.6% across all 9 scenarios as compared with the baseline scenario. When a reduction in feed efficiency by 19.2% was assumed, the herd-level CH4 intensity increased by up to 4.4% during 2 mo. Overall, our results showed large impacts of heat stress on both dairy production and CH4 emissions and suggest the need to implement management mitigation strategies in heat-stressed dairy herds.

Anina Vogt, Susanne Waiblinger, Rupert Palme et al.

ABSTRACT: Weaning and separation remain among some of the biggest challenges for cow-calf contact systems, making the development of practical and low-stress separation methods mandatory for future success of these systems. This study aimed to compare behavioral and physiological responses of dairy cows to separation from their calves after 3 mo of full-time contact, with either the 2-step method (NF, 2 wks full-time contact while calves wore a nose flap, 1 wk fence-line contact before total separation, n = 18) or by gradual reduction of contact time between cow and calf (GR, 1 wk half day contact, 1 wk morning contact, 1 wk fence-line contact before total separation, n = 18). Vocalizations and searching behavior were observed on 4 d/wk from 1 wk before separation until 1 wk after total separation. During the same period, lying behavior and rumination time was automatically assessed via accelerometers and pressure sensors. Fecal and blood samples were collected twice per week from day −1 until +23 relative to separation start for analysis of fecal cortisol metabolites and the immune response. Milk yield in the parlor was continuously recorded. Statistical analysis was conducted using linear mixed effects models. We found no difference between the 2 separation methods in any of the examined behavioral and physiological response variables. However, a significant increase in vocalizations and searching behavior compared with baseline was present with both methods. Furthermore, there was a transient increase in physiological distress markers and a short-lived retention of milk yield at initiation of treatments, indicating that both methods induced distress for the cows. Descriptively, there were large interindividual differences between cows as well as a different temporal distribution in occurrence of behavioral responses, as GR cows vocalized most frequently during the week with fence-line contact and after total separation from the calf, while NF cows reacted strongest during the 2 wk while calves wore the nose flap. Milk yield was higher in NF than GR cows during the 2 wk while GR calves had time-restricted access to their dams and NF calves were prevented from suckling, but showed no difference afterward. However, similar evening milk yields of GR cows in the weeks with half-day and morning contact, indicated that the weekly reductions in contact time worked in a rather stepwise than gradual manner, which warrants further improvement of the GR method. Taken together, results showed that cows experienced distress during separation with the GR method, when implemented over 3 wk in 3 steps, as well as with the NF method, but differences between individuals were considerable.

David P. Casper, Mark F. Scott

ABSTRACT: Protein-encapsulated fat (PEF) blends are routinely used for manufacturing calf milk replacers (MR). The use of PEF blends improves fat mixability to ensure MR when mixed and fed as a homogeneous solution for neonatal calves. A new alternative PEF based on choice white grease (CWG) has been developed to improve its mixability and solubility to ensure a homogeneous MR solution. The alternative PEF is hypothesized to support similar growth performance (ADG, DMI, and feed efficiency) of neonatal calves and potentially reduce costs. The study objective was to evaluate CWG PEF as an alternative to a standard animal lard–tallow (ALT) PEF blend to mix a MR to be fed to Holstein calves. A total of 40 Holstein bull calves (2–5 d old) were blocked by BW and randomly assigned to 1 of 2 treatments (n = 20/treatment) using a randomized complete block design. The treatments were (1) CWG used to manufacture a PEF blend, and (2) ALT used to manufacture a PEF blend. The PEF blends were then used to manufacture 2 experimental MR. Both MR were formulated to contain a ratio of 22% CP to 20% fat with Met, Lys, Thr, Trp, and Val AA specifications, and fed twice per day along with ad libitum 22% CP mini-pelleted calf starter (CS) and water. The MR were fed at 15% solids at 0630 and 1800 h, fed at 0.567 kg/d for d 1 to 14, increased to 0.85 kg/d for d 15 to 35, and reduced to once per day at 0.425 kg/d for d 36 to 42 to facilitate weaning at 42 d with ad libitum CS fed for the remainder of the 56-d study. Calves fed CWG and ALT PEF blends were similar (P > 0.10) in BW gain (37.4 and 35.9 kg for CWG and ALT, respectively), ADG (679.8 and 652.7 g/d), CS DMI intake (0.69 and 0.67 kg/d), total DMI (1.19 and 1.17 kg/d) and feed conversion (0.559 and 0.543 kg/kg). No significant differences were detected in frame gains and fecal scores among treatments. Choice white grease can be used to manufacture a PEF blend for use in manufacturing MR for feeding neonatal calves by maintaining growth performance and health at potentially lower cost.

Ernst Seidel, Gerald Enzner, Pejman Mowlaee et al.

Kalman filtering is a powerful approach to adaptive filtering for various problems in signal processing. The frequency-domain adaptive Kalman filter (FDKF), based on the concept of the acoustic state space, provides a unifying solution to the adaptive filter update and the related stepsize control. It was conceived for the problem of acoustic echo cancellation and, as such, is frequently applied in hands-free systems. This article motivates and briefly recapitulates the linear FDKF and investigates how it can be further supported by deep neural networks (DNNs) in various ways, specifically to overcome the challenges and limitations related to the usually required estimation of process and observation noise covariances for the Kalman filter. While the mere FDKF comes with very low computational complexity, its neural Kalman filter variants may deliver faster (re)convergence, better echo cancellation, and even exceed the FDKF in its excellent double-talk near-end speech preservation both under linear and nonlinear loudspeaker conditions. To provide a synopsis of the state of the art, this article contributes a comparison of a range of DNN-based extensions of FDKF in the same training framework and using the same data.

Rong Ye, Xue-Qin Jiang, Hui Feng et al.

Signed graphs, which are characterized by both positive and negative edge weights, have recently attracted significant attention in the field of graph signal processing (GSP). Existing works on signed graph learning typically assume that all graph nodes are available. However, in some specific applications, only a subset of nodes can be observed while the remaining nodes stay hidden. To address this challenge, we propose a novel method for identifying signed graph that accounts for hidden nodes, termed \textit{signed graph learning with hidden nodes under column-sparsity regularization} (SGL-HNCS). Our method is based on the assumption that graph signals are smooth over signed graphs, i.e., signal values of two nodes connected by positive (negative) edges are similar (dissimilar). Rooted in this prior assumption, the topology inference of a signed graph is formulated as a constrained optimization problem with column-sparsity regularization, where the goal is to reconstruct the signed graph Laplacian matrix without disregarding the influence of hidden nodes. We solve the constrained optimization problem using a tailored block coordinate descent (BCD) approach. Experimental results using synthetic data and real-world data demonstrate the efficiency of the proposed SGL-HNCS method.

Hewa Babarandage Chathurika Harshani, Dilshani Kavindya Balasuriya, Wickramasinghe Widana Pathirana Pragathi Nirasha Diwyanjalee et al.

Background: Listeria monocytogenes, a foodborne pathogen, poses a significant risk to public health due to its potential to cause severe infections termed &quot;listeriosis&quot;. Raw milk and dairy products are common vehicles for L. monocytogenes transmission, amplifying the risk to consumers. Additionally, the emergence of antibiotic resistance in Listeria strains heightens concerns in human and veterinary medicine. Aim: This study aimed to assess the prevalence of L. monocytogenes in raw milk samples from Sri Lanka&apos;s Colombo district and to characterize the antibiotic resistance patterns of positive isolates. Methods: One hundred raw milk samples were collected from various milk collection centers. Samples were sourced from locations including Awissawella, Kahanthota, Meepe, Homagama, and Udahamulla. Antibiotic resistance was evaluated using standard methods like disk diffusion and well diffusion, testing ampicillin, penicillin, streptomycin, and tetracycline. Results: Of the 100 samples, L. monocytogenes was detected by conventional PCR in 83, with Awissawella having the highest occurrence (100%), followed by Kahanthota (81.81%), Meepe (81.48%), Homagama (77.27%), and Udahamulla (44.44%). Among the positive samples, 72 showed varying degrees of antibiotic resistance. The highest level of resistance was observed for penicillin (83.1%), followed by ampicillin (65%), streptomycin (32.53%), and tetracycline (10.84%). Sixty isolates (60%) displayed resistance to more than one antibiotic studied. Findings also revealed the widespread manual milking, predominant water usage over soap for hygiene, and common daily bathing of cows, highlighting the need for improved hygiene practices to minimize contamination risks in dairy farming. Conclusion: Raw milk contaminated with L. monocytogenes pose a serious public health risk. The study highlights the need for stringent hygiene measures in milk production and processing to safeguard consumers. Additionally, the high prevalence of antibiotic-resistant strains underscores the importance of judicious antibiotic use in both human and veterinary medicine to mitigate the further emergence and spread of resistant Listeria strains. [J Microbiol Infect Dis 2024; 14(2.000): 67-79]

Ibrahim Ozkan, Atila Yilmaz

Cardiovascular system diseases can be identified by using a specialized diagnostic process utilizing a digital stethoscope. Digital stethoscopes provide phonocardiography (PCG) recordings for further inspection, besides filtering and amplification of heart sounds. In this paper, a framework that is useful to develop feature extraction and classification of PCG recordings is presented. This framework is built upon a previously proposed segmentation algorithm that processes a feature vector produced by the agglutinate application of Mel-frequency cepstrum and discrete wavelet transform (DWT). The performance of the segmentation algorithm is also tested on a new data set and compared to the previously reported results. After identifying the fundamental heart sounds and segmenting the PCG recordings, five principal features are extracted from the time domain signal and Mel-Frequency cepstral coefficients (MFCC) of each cardiac cycle. Classification outcomes are reported for three nonlinear models: k nearest neighbor (k-NN), support vector machine (SVM), and multilayer perceptrons (MLP) classifiers in comparison with a linear approach, namely Mahalanobis distance linear classifier. The results underline that although neural networks and linear classifier show compatible performance in basic classification problems, with the increase in the nonlinearity of the classification problem their performance significantly vary.

Elias Zea, Marco Laudato, Joakim Andén

Sparse representation systems that encode signal architecture have had a profound impact on sampling and compression paradigms. Remarkable examples are multi-scale directional systems, which, similar to our vision system, encode the underlying architecture of natural images with sparse features. Inspired by this philosophy, we introduce a representation system for wave-based acoustic signal processing in 2D space--time, referred to as the \emph{boostlet transform}, which encodes sparse features of natural acoustic fields using the Poincaré group and isotropic dilations. Boostlets are spatiotemporal functions parametrized with dilations, Lorentz boosts, and translations in space--time. Physically speaking, boostlets are supported away from the acoustic radiation cone, i.e., having broadband frequency with phase velocities other than the speed of sound, resulting in a peculiar scaling function. We formulate a discrete boostlet frame using Meyer wavelets and bump functions and examine its sparsity properties. An analysis with experimentally measured fields indicates that discrete boostlet coefficients decay significantly faster and attain superior reconstruction performance than wavelets, curvelets, shearlets, and wave atoms. The results demonstrate that boostlets provide a natural, compact representation system for acoustic waves in space-time.