Aerobic Storage Research Articles

Microbiome Evolution of Brewer’s Spent Grain and Spent Coffee Ground Solid Sidestreams Under Industrial Storage Conditions

Brewer’s spent grain (BSG) and spent coffee ground (SCG) are solid sidestreams from beverage production increasingly being upcycled into food, feed and other value-added products. These solid sidestreams are prone to microbial spoilage, negatively impacting their upcycling potential. Three samples each of BSG and SCG were obtained from generators and recycling facilities in Singapore, and their chemical, elemental, and microbial composition was characterized. The spoilage mechanisms were investigated during storage under anaerobic and aerobic conditions. Bacterial loads of sidestreams were low from craft brewery and café sources (<1 and 3.53 ± 0.03 log10 CFU/g) and high from recycling facilities (>6 log10 CFU/g). The microbiome of BSG from recycling facilities was dominated by Bacilli, and B. coagulans was identified as the most prevalent species. SCG from recycling facilities was dominated by lactic acid bacteria, with L. panis being the most prevalent species. Storage up to 14 days under anaerobic conditions led to further bacterial proliferation mainly by Bacilli, lactic acid bacteria, and acetic acid bacteria, while aerobic storage led to extensive fungal contamination, including potential aflatoxin-producing Aspergillus flavus. The results shed light on the spoilage mechanisms, while highlighting the short shelf-life and food safety risks of BSG and SCG to inform valorization strategies.

Evaluation of storage stability of poultry by-product meal incorporated fish feed under aerobic storage condition

The research focused on development of fish feed utilising poultry by-product meal (PBM) as a substitute for fish meal (FM) and evaluating its shelf life under aerobic packaging conditions. Initially, a basal diet (C) was formulated to meet the nutritional requirements for optimal growth of Tilapia by using FM as the major protein source. After analysing the nutritional composition of PBM, an isoproteinaceous diet (T) was formulated by replacing FM with PBM. The product was packed in HDPE bags and kept at room temperature and analysed for physico chemical and microbial characteristics for 45 days at weekly intervals. Moisture content of both C and T decreased significantly (p0.05) was found between C and T. The TBARS value of both C and T followed an increasing trend. This increase in C was not significant (p<0.01) between 28th and 35th day, and between 42nd and 45th day but that of T increased significantly (p<0.01) throughout the storage period. T consistently displayed the highest TBARS value during storage period. Tyrosine Value (TV) of both C and T also increased during storage and was significant (p<0.01) up to 42nd day of storage. C exhibited the highest TV throughout the storage period. Similarly, total viable count (TVC) of both C and T increased on storage. The increase in TVC for C was not significant (p<0.01) between 21st and 28th days, whereas that of T was significant (p<0.01) throughout the storage period. On 45th day, T exhibited highest count and was significantly different (p<0.01) from C. Throughout the 45-day storage period, no observable coliform count or yeast and mould count was noted in either C or T. The present study indicated that fish feed can be effectively prepared by utilising PBM and can be stored under room temperature up to 45 days. Keywords: Poultry by-product meal, fish meal, fish feed, storage stability

Greenhouse gas and volatile organic compound emissions of additive-treated whole-plant maize silage: part A—anaerobic fermentation period

BackgroundSilage emits climate- and environment-relevant gases during fermentation and feed-out periods. This trial aimed to determine the unknown carbon dioxide (CO2), methane, nitrous oxide, ethanol, and ethyl acetate emissions of constant maize silage material over both periods. The results will be published in two consecutive articles (Part A: anaerobic fermentation period, Part B: aerobic storage period).MethodsThe untreated control (CON) was compared with the chemical additive treatment (CHE; 0.5 g sodium benzoate and 0.3 g potassium sorbate per kg fresh matter) and the biological additive treatment (BIO; 108 colony-forming units (CFU) Lentilactobacillus buchneri and 107 CFU Lactiplantibacillus plantarum per kg fresh matter). Barrel silos (n = 4) were connected to gas bags to quantify gas formation during anaerobic fermentation (30 or 135 ensiling days). Glass jar silos (n = 12) were used for laboratory silage analysis.ResultsCHE produced significantly (p < 0.05) less gas (6.7 ± 0.3 L per kg dry matter ensiled material (kgDM) until ensiling day 14.0 ± 0.0) and ethanol (8.6 ± 1.5 mg kgDM–1) than CON did (8.5 ± 0.2 L kgDM–1 until ensiling day 19.5 ± 6.4; 12.2 ± 1.5 (mg ethanol) kgDM–1). BIO indicates prolonged gas formation (9.1 ± 0.9 L kgDM–1 until ensiling day 61.3 ± 51.9; 12.0 ± 2.1 mg kgDM–1). CO2 is the main component of the gas formed. All treatments formed methane and nitrous oxide in small quantities. CON emitted significantly more CO2eq emissions than BIO and less than CHE (p < 0.05). Additives had no effect on ethyl acetate gas emissions. For BIO, ethanol concentrations in the material (rS = 0.609, p < 0.05) and gas quantities (rS = 0.691, p < 0.05) correlate with ethyl acetate gas quantities. All the treatments exhibited decreasing gas and CO2 quantities, and the dry matter mass increased between ensiling days 14 and 30 (− 0.810 ≤ rS ≤ 0.442; p < 0.05 to p = 0.20).ConclusionSilage generates climate- and environmental-relevant gases during fermentation and silage additives affect this pattern. Gas formation exceeds the fixation potential, and the carbon footprint of silage fermentation is negative.Graphical

Effect of the Bioprotective Properties of Lactic Acid Bacteria Strains on Quality and Safety of Feta Cheese Stored under Different Conditions.

Lately, the inclusion of additional lactic acid bacteria (LAB) strains to cheeses is becoming more popular since they can affect cheese's nutritional, technological, and sensory properties, as well as increase the product's safety. This work studied the effect of Lactiplantibacillus pentosus L33 and Lactiplantibacillus plantarum L125 free cells and supernatants on feta cheese quality and Listeria monocytogenes fate. In addition, rapid and non-invasive techniques such as Fourier transform infrared (FTIR) and multispectral imaging (MSI) analysis were used to classify the cheese samples based on their sensory attributes. Slices of feta cheese were contaminated with 3 log CFU/g of L. monocytogenes, and then the cheese slices were sprayed with (i) free cells of the two strains of the lactic acid bacteria (LAB) in co-culture (F, ~5 log CFU/g), (ii) supernatant of the LAB co-culture (S) and control (C, UHT milk) or wrapped with Na-alginate edible films containing the pellet (cells, FF) or the supernatant (SF) of the LAB strains. Subsequently, samples were stored in air, in brine, or in vacuum at 4 and 10 °C. During storage, microbiological counts, pH, and water activity (aw) were monitored while sensory assessment was conducted. Also, in every sampling point, spectral data were acquired by means of FTIR and MSI techniques. Results showed that the initial microbial population of Feta was ca. 7.6 log CFU/g and consisted of LAB (>7 log CFU/g) and yeast molds in lower levels, while no Enterobacteriaceae were detected. During aerobic, brine, and vacuum storage for both temperatures, pathogen population was slightly postponed for S and F samples and reached lower levels compared to the C ones. The yeast mold population was slightly delayed in brine and vacuum packaging. For aerobic storage at 4 °C, an elongation in the shelf life of F samples by 4 days was observed compared to C and S samples. At 10 °C, the shelf life of both F and S samples was extended by 13 days compared to C samples. FTIR and MSI analyses provided reliable estimations of feta quality using the PLS-DA method, with total accuracy (%) ranging from 65.26 to 84.31 and 60.43 to 89.12, respectively. In conclusion, the application of bioprotective LAB strains can result in the extension of feta's shelf life and provide a mild antimicrobial action against L. monocytogenes and spoilage microbiota. Furthermore, the findings of this study validate the effectiveness of FTIR and MSI techniques, in tandem with data analytics, for the rapid assessment of the quality of feta samples.

Effect of cattle and horse feces storage methods on Nematode egg viability and sensitivity for egg hatch test

The aim of the present study was to validate methods of stool sample conservation for the egg hatch test (EHT). This study involved the use of a bovine naturally infected predominantly by Cooperia spp. and one equine naturally infected predominantly by cyathostomins characterized as susceptible to benzimidazoles in the EHT. Fecal samples were submitted to three treatments: aerobic methods (anaerobic storage in plastic bottles, anaerobic storage in vacuum-sealed bags or aerobic storage in plastic bags), under two temperature conditions (room temperature and refrigeration) analyzed at four different assessment times (48, 72, 96 and 120 h). As the standard test, an assay was also performed within 3 h. The tests were performed in triplicate for each drug concentration and with three experimental repetitions at one-week intervals. Two criteria were used for the storage methods: hatchability in the negative control group and sensitivity of the eggs to thiabendazole, comparing the EC50 and 95% confidence interval for each treatment to those of the standard test and the other repetitions. Bovine samples can be stored for up to 96 h and refrigerated vacuum storage can be used, ensuring hatchability of the negative control and sensitivity of the eggs to thiabendazole. For equine samples, no forms of storage were indicated due to the variation among the repetitions and the reduction in the sensitivity of the eggs to thiabendazole, which could result in a false positive detection of resistance.

Can a functional cheese spread incorporating Akkermansia muciniphila deliver beneficial physicochemical and biological properties while enhancing probiotic stability and viability during aerobic storage and in vitro digestion?

In the present study, next generation probiotic Akkermansia muciniphila was incorporated into a dairy matrix containing Portuguese whey cheese and Greek-style yoghurt in a proportion of 3.5:1, respectively. Subsequently, this innovative food was characterized in terms of microbiological and physicochemical parameters, total phenolic content and antioxidant, antidiabetic, and antihypertensive activities, as well as its protective effect on A. muciniphila viability during 21 d of refrigerated aerobic storage and when subjected to simulated gastrointestinal passage. The probiotic cheese spread displayed high microbiological quality, low total phenolic content (0.36 mg gallic acid equivalents/g of dried cheese) and interesting biological activities, including antidiabetic (98.10% α-glucosidase inhibition) and antihypertensive (49.18% angiotensin converting enzyme inhibition). Simultaneously, this food ensured a high A. muciniphila viability (>108 CFU/g) during 21 d of refrigerated aerobic storage with subsequent in vitro digestion. Additionally, this probiotic cheese presented a similar profile in terms of texture, color, water activity and pH when compared to the cheese control (without A. muciniphila), suggesting a potentially high acceptance among consumers. In conclusion, the developed cheese spread seems to be a promising and suitable food vector to safeguard A. muciniphila viability during refrigerated aerobic storage for at least 21 d with subsequent gastrointestinal passage.

Adjusting ram semen preservation: Exploring the impact of oxygen exposure during liquid storage.

This study investigated the effects of storage conditions on the quality of chilled ram semen stored at 4°C for 48 h, comparing aerobic and anaerobic conditions. Ejaculates from INRA180 rams were collected and stored under both conditions, with assessments at 0-, 24-, and 48-h intervals. Various sperm parameters were examined, including motility, velocity, viability, morphology, membrane integrity, and lipid peroxidation. Results showed that storage duration significantly impacted sperm quality, leading to a gradual decline from 0 to 24 h and 24 to 48 h. Notably, after the initial 24 h, progressive motility (PM) and membrane integrity (MI) demonstrated distinct responses to storage conditions. Anaerobic storage consistently improved PM and MI values compared to aerobic storage between 24 and 48 h. Anaerobic conditions also enhanced viability and reduced abnormality at the 48-h mark. Total motility remained stable throughout storage. Velocity parameters (VCL: curvilinear velocity; VSL: straight velocity and VAP: velocity average path) exhibited differences between the 24- and 48-h intervals, with anaerobic storage resulting in higher VAP and VSL values. Moreover, lipid peroxidation exhibited a progressive increase from 0 to 24 h and 24 to 48 h, independent of storage conditions. Remarkably, anaerobic storage consistently yielded lower lipid peroxidation levels compared to aerobic storage, regardless of storage duration. In conclusion, this study highlights that the anaerobic storage proved advantageous for chilled ram semen quality, particularly after the initial 24 h.

A new HS-SPME-GC-MS analytical method to identify and quantify compounds responsible for changes in the volatile profile in five types of meat products during aerobic storage at 4 °C

Nowadays, it is important to monitor the freshness of meat during storage to protect consumers’ health. Volatile organic compounds (VOCs) are responsible for odour and taste of food, and they give an indication about meat quality and freshness. This study had the aim to seek and select potential new markers of meat spoilage through a semi-quantitative analysis in five types of meat (beef, raw and baked ham, pork sausage and chicken) and then to develop a new quantitative analytical method to detect and quantify potential markers on five types of meat simultaneously. Firstly, a new headspace-solid phase microextraction-gas chromatography-mass spectrometry (HS-SPME-GC–MS) method was developed to evaluate the volatile profile of five types of meat, preserved at 4 °C for 5 days. Among the 40 compounds identified, 15 were chosen and selected as potential shelf-life markers on the basis of their presence in most of meat samples or/and for their constant increasing/decreasing trend within the sample. Afterwards, a quantitative HS-SPME-GC–MS analytical method was developed to confirm which VOCs can be considered markers of shelf-life for these meat products, stored at 4 °C for 12 days. Some of the compounds analyzed attracted attention as they can be considered markers of shelf-life for at least 4 types of meat: 1-butanol, 3-methylbutanol, 1-hexanol, 2-nonanone, nonanal, 1-octen-3-ol and linalool. In conclusion, in this study a new quantitative HS-SPME-GC–MS analytical method to quantity 15 VOCs in five types of meat was developed and it was demonstrated that some of the compounds quantified can be considered markers of shelf-life for some of the meat products analyzed.

Aerobic digestibility of waste aerobic granular sludge (AGS) assessed by respirometry, physical-chemical analyses, modeling and 16S rRNA gene sequencing

Research has evolved on aerobic granular sludge (AGS) process, but still there are very few studies on the treatment of excess AGS sludge, with almost none considering its aerobic digestion. Here therefore, the aerobic digestibility of typical AGS sludge was assessed. Granules were produced from acetate-based synthetic wastewater (WW) and were subjected to aerobic digestion for 64 d. The stabilization process was monitored over time through physical-chemical parameters, oxygen uptake rates (OUR) and 16S rRNA gene sequencing. The microbial analyses revealed that the cultivated granules were dominated by slow-growing bacteria, mainly ordinary heterotrophic organisms with potential for polyhydroxyalkanoates (PHA) aerobic storage (PHA-OHOs), polyphosphate and glycogen accumulating organisms (PAOs and GAOs), fermentative anaerobes and nitrifiers (AOB and NOB). Differential abundance analysis of the bacterial data (before versus after digestion) discriminated between the most vulnerable microbiome genera and those most resistant to aerobic digestion. Furthermore, modeling of the stabilization process determined that the endogenous decay rate constant (bH) for the heterotrophs present in the granules was notably low; bH = 0.05 d−1 (average), four times less than for common activated sludge (AS), which is rated at 0.2 d−1. For first time, the research reveals another important feature of AGS sludge, i.e. the slow-decaying character of its bacteria (along with their known slow-growing character). This results in slower stabilization, need of bigger digesters and reconsideration of the specific OUR limits in biosolids regulations (SOUR limit of 1.5 mg/gTSS.h), for waste AGS compared to conventional waste AS. The study suggests that aerobic digestion of waste AGS (fully-granulated) could differ from that of conventional AS. Future work is needed on aerobic digestibility of real AGS sludges from municipal and industrial WWs, compared to synthetic WWs.

Evaluation of plasma-activated lactic-gallic acid treated chicken meats on the freshness, volatile changes, and metabolites through multi-analytical techniques

Various techniques were employed to evaluate freshness, volatile changes, and metabolites in chicken meat treated with plasma-activated lactic-gallic acid. Collectively 96 slices and 216 cubes of chicken breasts and drumsticks were immersed in deionized water (control), a mixture of lactic and gallic acids (0.3% lactic and 0.3% gallic; LGA), plasma-activated deionized water, or PLGA for 10 min. A synergistic effect of plasma was observed with low-concentration LGA in preserving meat quality and color over 8-day aerobic storage (4 °C). On day 8, PLGA-treated breasts and drumsticks exhibited a significant reduction in bacterial spoilage by 0.69 and 0.50 log CFU/g, respectively, compared to control treatment. They also showed the low levels of 2-thiobarbituric acid reactive substances, respectively, as opposed to others. PLGA effectively sanitized and improved meat quality during storage. Multi-analytical techniques revealed strong correlations between anserine and taurine as antioxidants, linking them with freshness and chemical changes in chicken meat. Industrial relevanceCold atmospheric plasma is FDA-approved for surgical trials, while its potential in the food industry is currently under evaluation and gaining global attention. The combination of plasma and low-concentration lactic-garlic acid (LGA) holds significant promise for expanding markets by preserving color, and fortifying antimicrobial and antioxidant properties of chicken meat. In this study, PLGA treatment enhances chicken meat quality compared to other treatments, reducing microbial growth by up to 17%, lowering lipid oxidation by up to 12%, and improving volatile changes during storage. Additionally, it establishes a robust foundation for using multi-analytical techniques to correlate chicken meat freshness and chemical changes with direct relevance to the food industry.

Influence of three different manure treatments on antimicrobial resistance genes and mobile genetic elements

There is a growing concern about the potential dissemination of antimicrobial resistance into agricultural fields due to the application of manure as crop fertilizer. While reducing the usage of antibiotics in livestock production stands as the first alternative to prevent this problem, there is evidence that this may not be enough to eliminate antimicrobial resistance elements already present in manure microbiomes. This study employed a metagenomic approach to investigate the impact of common manure treatments, including aerobic storage, mesophilic anaerobic digestion (MAD), and solid-liquid separation, on the presence and abundance of antimicrobial resistance genes (ARGs), bactericides, and heavy metal resistance genes (BacMet), and mobile genetic elements (MGEs) in manure from three different farms, including one operating in an antibiotic-free environment. The results indicated that MAD was the best method to reduce the numbers of ARGs, BacMet, and MGEs, achieving reduction rates greater than 40%, 89%, and 68%, respectively. Manure storage significantly reduced BacMet levels (over 30%) and MGEs (28%) but had no significant effect on total ARG levels. Solids recovered through solid-liquid separation exhibited elevated levels of ARGs, BacMet, and MGEs, while the liquid fraction displayed levels similar to untreated manures. Correlation and co-occurrence modeling analyses indicated that changes in microbial communities, particularly fluctuations in aerobic and facultative communities belonging to Bacillota, Actinomycetota, and Pseudomonadota phyla, played a significant role in driving changes in ARGs, BacMet, and MGEs. The results also showed the presence of toxin-antitoxin and transposon systems near different ARGs. Overall, the results confirmed that genes conferring resistance to various antimicrobials and MGE capable of mobilizing them are widely spread in dairy farms; that even under the absence of antibiotics, the use of heavy metals and disinfectants may promote the maintenance of ARGs and MGEs, and; that treatment such as anaerobic digestion could reduce the risk of the spread of antimicrobial resistance.

Development of a Protocol for Anaerobic Preparation and Banking of Fecal Microbiota Transplantation Material: Evaluation of Bacterial Richness in the Cultivated Fraction.

Fecal microbiota transplantation (FMT) has shown highly variable results in indications beyond recurrent Clostridioides difficile infection. Microbiota dysbiosis in many diseases is characterized by the depletion of strictly anaerobic bacteria, which may be crucial for FMT efficacy. We developed a protocol to ensure anaerobic conditions during the entire transplant preparation and banking process, from material collection to administration. The protocol necessitates an anaerobic cabinet, i.e., a non-standard laboratory equipment. We analyzed the population of viable anaerobes by combining cultivation and 16S rRNA gene profiling during the transplant preparation, and after 4, 8, and 12 months of anaerobic or aerobic storage at -80 °C, 78% of fecal species were captured via cultivation. Our findings suggest that strictly anaerobic transplant preparation and storage may preserve species richness better than oxic conditions, but the overall difference was not significant. However, specific anaerobes such as Neglecta and Anaerotruncus were affected by the oxygen exposure. A storage time of up to 12 months did not affect the presence of cultivated taxa. Noteworthy, our analysis focused on the richness of cultivated anaerobes rather than their abundance, which may have been affected. The benefits of the developed anaerobic protocol in FMT for specific indications remain to be demonstrated in clinical trials.

Akkermansia muciniphila Encapsulated in Calcium-Alginate Hydrogelated Matrix: Viability and Stability over Aerobic Storage and Simulated Gastrointestinal Conditions.

Akkermansia muciniphila is considered a next-generation probiotic to be incorporated in new food and pharmaceutical formulations. Effective delivery systems are required to ensure high probiotic viability and stability during product manufacture, shelf-life, and post-consumption, namely, throughout digestion. Hydrogelated matrices have demonstrated promising potential in this dominion. Hence, this work aimed to evaluate the effect of a calcium-alginate hydrogelated matrix on A. muciniphila viability during 28-days refrigerated aerobic storage and when exposed to simulated gastrointestinal conditions, in comparison with that of free cells. Akkermansia muciniphila was successfully encapsulated in the calcium-alginate matrix via extrusion (60% encapsulation yield). Furthermore, encapsulated A. muciniphila exhibited high stability (a loss in viability lower than 0.2 log-cycle) after 28-days of refrigerated aerobic storage, maintaining its viability around 108 CFU/g. Prominently, as the storage time increased, encapsulated A. muciniphila revealed higher viability and stability regarding in vitro gastrointestinal conditions than free cells. This suggests that this encapsulation method may attenuate the detrimental effects of prolonged aerobic storage with a subsequent gastrointestinal passage. In conclusion, encapsulation via extrusion using a calcium-alginate hydrogelated matrix seems to be a promising and adequate strategy for safeguarding A. muciniphila from adverse conditions encountered during refrigerated aerobic storage and when exposed to the gastrointestinal passage.

Identification of dominant spoilage bacteria, bacterial diversity analysis, and antibacterial exploration of chilled monkfish

In this study, we aimed to investigate spoilage bacteria in monkfish stored under vacuum and aerobic (air) refrigeration at 4 °C for the first time. In vitro bacterial cultures, coupled with Sanger sequencing of genes, were used to isolate and identify 21 and 31 bacterial strains from vacuum-packed and aerobically packed monkfish, respectively. The isolated strains were back-inoculated into sterile fish blocks and inactivated fish juice. Our findings revealed that Carnobacterium, Shewanella, Vagococcus, Myroides, and Psychrobacter increased the production of total volatile base nitrogen (TVB-N) and trimethylamine (TMA) from monkfish. Monkfish showed a decrease in bacterial flora diversity with storage time, the emergence of dominant species during the spoilage process, and differences in bacterial growth tolerance in different packaging forms, resulting in variability in bacterial community structure. Shewanella accelerated the spoilage of monkfish in both packaging forms. Vagococcus and Psychrobacter were numerically dominant in both storage forms. Unlike some spoilage bacteria in refrigerated fish, Carnobacterium (11.72%) and Myroides (9.01%) were the specific spoilage bacteria in vacuum and aerobic storage at 4 °C, respectively. Furthermore, a combination of nisin (NS), ε-polylysine (ε-PL), and citric acid (CA) significantly reduced the survival rate of dominant spoilage bacteria and the total viable bacterial count in monkfish.

Incorporation of Bifidobacterium animalis subspecies lactis BB-12® and Akkermansia muciniphila in chocolate matrices

Chocolate is a food product highly popular worldwide, and it has been proposed as a carrier for probiotic delivery. This work evaluated the viability of probiotic strains, Bifidobacterium animalis subsp. lactis BB-12® and Akkermansia muciniphila DSM 22959, in chocolate matrices with different cocoa percentages (33.6; 54.5 and 70.5%) throughout 28-days of aerobic storage. The pH, total phenolic content and antioxidant, antidiabetic, and antihypertensive activities were also determined at timepoints of 0 and 28-days. During storage, all chocolates showed high pH stability (variations lower than 1 unit) and it was observed a growing trend in total phenolic content and in bioactivities with the increase of cocoa content in the matrix. Regarding probiotic viability, a higher level for B. animalis subsp. lactis BB-12® was achieved in chocolate containing 70.5% cocoa (estimated in 108 CFU/g after storage). In opposite, A muciniphila DSM 22959 exhibited greater viability in chocolate with 33.6% and 54.5% cocoa (around 106 CFU/g after storage, meeting the minimum required amounts for probiotic products). Conjugating the data from physicochemical properties, bioactivities and probiotic viability, dark chocolate matrices with 54.5% and 70.5% cocoa, may be considered a promising food vector for A. muciniphila DSM 22959 and B. animalis subsp. lactis BB-12®, respectively.

Oxidative Effects of Raw Chickpea in Reformulated Pork Patties: Level of Chickpea, Temperature, and Use of Selected Natural Antioxidants

Raw pulses as extenders in meat preparations result in oxidative processes. The oxidative effects of using a raw chickpea paste (CP; 1/2; chickpea/water) in pork patties were evaluated. In a first experiment, patties were prepared with increasing levels of CP (0 to 25%); in a second experiment, patties with CP (25%) and without CP (controls) were kept at 4 °C or 22 °C for 18 h before patty production; in a third experiment, chitosan, garlic, and cumin (from 0.5 to 2%) were added in patties with CP (25%) and controls, and their antioxidant effects were evaluated. Patties were analysed for pH, colour, and thiobarbituric acid reactive substances (TBARS) on days 1, 3, and 7 of refrigerated aerobic storage. Discoloration on day 1 and TBARS levels on days 1 to 7 of storage increased with the CP used. Higher batter temperature after mixing did not activate oxidative processes in the CP patties. Garlic showed pro-oxidant effects in controls and no effects in the CP patties. Chitosan and cumin did not reduce CP patties oxidation on the first day of storage, but they controlled oxidation during subsequent storage. More research is needed to prevent oxidation caused by using raw chickpeas in meat preparations.

Microflora, Contents of Polyamines, Biogenic Amines, and TVB-N in Bovine Offal and Game Meat for the Raw-Feeding of Adult Dogs.

Microflora and contents of biogenic amines/polyamines and total volatile basic nitrogen (TVB-N) in 99 samples of bovine offal (red offal, n = 41 and other offal and mixes, n = 45) and wild game meat (n = 13) for raw meat-based diets (RMBD) for dogs were analyzed. Samples were bought in 11 local pet food shops and in one game-handling establishment in Austria (Lower Austria, Styria, and Vienna) in September and October 2022. Median contents (first and third quartiles in brackets) of cadaverine, histamine, tyramine, spermidine, and spermine were 20.7 [16.7; 28.6]; 25.4 [17.1; 47.2]; 18.9 [13.6; 38.9]; 15.2 [11.2; 21.2]; and 41.9 [<limit of detection; 64.5] mg/kg wet weight, respectively. The sum of putrescine + cadaverine + histamine + tyramine was >50 mg/kg in 85.9% of samples, indicating the use of low-quality ingredients or inappropriate storage conditions. However, only 10.1% of samples were determined to be not compliant with a maximum amine content proposed for pet food. Median contents of the total aerobic bacteria counts (TACs), Pseudomonas, and Enterobacteriaceae were 7.4 [6.4; 8.0]; 6.5 [5.5; 7.7]; and 4.8 [3.9; 5.6] log CFU/g, respectively, with significantly lower counts in red offal RMBD (p < 0.05). TVB-N exceeded 150 mg/kg in 87.9% of samples. The TACs and Enterobacteriaceae numbers in red offal RMBD were comparable to those in food-grade red offal after 6 days of aerobic storage at 7 °C, i.e., temperatures higher than required for food-grade offal, but acceptable for animal by-products intended for RMBD production. In 80.8% of samples, numbers of Enterobacteriaceae exceeded the EU legal limit. From 12 of these samples, Salmonellae was able to be isolated, with counts from 0.03 MPN/g to 110 MPN/g. Salmonella enterica ser. Montevideo (n = 3), and S. enterica ser. Give and S. enterica ssp. Diarizonae (n = 2 each) were the most frequently isolated, while Listeria monocytogenes was rarely recovered (2%). Whilst exposure of humans handling such pet food can be reduced by hygiene precautions, the risk remains that dogs can acquire a feed-borne salmonellosis and shed the pathogen.

Effects of Alfalfa Hay to Oat Hay Ratios on Chemical Composition, Fermentation Characteristics, and Fungal Communities during Aerobic Exposure of Fermented Total Mixed Ration

The application of fermented total mixed ration (FTMR) is an effective method to prolong the use time of feed, but the understanding of the interaction mechanism between fungal microorganisms and silage quality and aerobic stability in FTMR is still limited. This study aimed to evaluate the effects of alfalfa (Medicago sativa L.) hay to oat (Avena sativa L.) hay ratios on chemical composition, fermentation characteristics, and fungal communities during aerobic exposure of fermented total mixed ration (FTMR). The supplement levels of oat were as follows: 200 g/kg oat hay (LO), 300 g/kg oat hay (MO), and 400 g/kg oat hay (HO). The water content of the three treatments was adjusted to 50% using a sprayer. After 60 days of ensiling, the bags were opened, and the chemical composition, fermentation characteristics, and fungal communities were measured after 3, 6, 9, and 12 days of aerobic exposure. The results suggested that the LO treatment significantly (p &lt; 0.05) increased the aerobic stability than that in other treatments. The crude protein and lactic acid content in the three treatments were significantly decreased with the extension of the aerobic exposure period. Additionally, there was a remarkable (p &lt; 0.05) higher lactic acid content observed in the LO treatment than that in the HO treatment during the aerobic stage. The PCoA showed that the compositions of the fungal community in the HO treatment were distinctly separated from the other two treatments. Compared with HO and LO treatments, the MO treatment observed relatively higher OTU, Shannon, and Chao1 indexes. Compared with LO and MO treatments, the abundances of the genes Saccharomyces and Wallemia were greater increased and decreased in the HO treatment, respectively. Integrated correlation analysis also underscores a possible link between the fermentation characteristics, aerobic stability, and significantly altered fungal community. This study suggested that the use of FTMR in production might prolong aerobic storage time when alfalfa was fermented in a mixture with ≤30% oat.

Exploring Freeze-Drying as Strategy to Enhance Viability of Faecalibacterium duncaniae DSM 17677 upon Aerobic Storage and Gastrointestinal Conditions

Faecalibacterium duncaniae is an intestinal commensal bacterium proposed as a next-generation probiotic due to its promising outcomes in the treatment and prevention of several human diseases, which demonstrate its multiple contributions to the host’s health. However, its strict anaerobic nature has created several hurdles in the development of functional foods, nutraceuticals, and biotherapeutic products. Herein, we explored freeze-dried formulations containing prebiotics, cryoprotectants, and antioxidant agents as a technological strategy to enhance the viability of F. duncaniae DSM 17677 upon aerobic storage and gastrointestinal tract conditions. Our results indicate that freeze-dried F. duncaniae in a matrix containing inulin, sucrose, cysteine, and riboflavin survived at levels higher than 106 CFU/g and around 105 CFU/g after 1 and 4 days of aerobic storage at room temperature, respectively. Thus, the freeze-dried formulation with inulin, sucrose, cysteine, and riboflavin presents as a protective strategy to improve F. duncaniae viability under aerobic environments. Nevertheless, incorporation of a suitable coating aimed at protecting F. duncaniae against the detrimental gastrointestinal passage effects is urgently required, given its high susceptibility to extreme acidic pH values and bile.

Effects of Chitosan Coatings on Controlling Listeria monocytogenes and Methicillin-Resistant Staphylococcus aureus in Beef and Mutton Cuts

Ruminant meat is considered to be a potent vehicle of foodborne pathogen transmission. Edible coatings are considered to be promising for enhancing meat safety. Here, edible chitosan membranes were applied to whole cuts of beef and mutton to test the survival of the pathogenic bacteria Listeria monocytogenes and methicillin-resistant Staphylococcus aureus. Meat pieces weighing approximately 200 g were inoculated with a cocktail of three S. aureus isolates or four L. monocytogenes isolates (6.00 log10CFU/g). The meat pieces were encased in a chitosan coating formed by immersion and incubated aerobically or vacuum-packaged in LDPE/PA/LDPE bags for up to 21 days. A decrease in both S. aureus (x = −1.95 log10CFU/g, standard error = 0.23 log10CFU/g) and L. monocytogenes counts (x = −1.07 log10CFU/g, standard error = 0.26 log10CFU/g) was observed. No significant differences were observed between L. monocytogenes-spiked beef and mutton pieces; statistically higher S. aureus counts were observed in mutton versus beef under similar treatments. Aerobic storage of meat pieces inoculated with L. monocytogenes enhanced the antibacterial effects of chitosan—a trend that was not observed in meat pieces inoculated with S. aureus. According to the results, edible chitosan membranes were effective in controlling the growth of S. aureus and L. monocytogenes.