Effects of Packaging Systems on the Natural Microflora and Acceptability of Chicken Breast Meat

The Effect of Corn and Wheat Glutens Fed to Lambs on Some Microbial and Chemical Properties of Musculus Longismus Dorsi and Determination of Intramuscular and Tail Fatty Acid Profile

This study examined the effects of wheat and corn gluten added to lamb diets as a unilateral protein source on some microbial and chemical properties of Musculus Longismus dorsi (LD), determination of intramuscular and tail fat profile. It was found that TBARS levels in LD muscle on the days of storage were highest in the wheat gluten-treated groups (p<0.01). It was found that the changes in pH values in LD muscle were different on days (p<0.05). It was found that the change of L*, a ve b values on days differed between groups during the storage period (p<0.05). It was found that the numbers of TMAB, Enterobacteriaceae, Lactobacillus spp., Pseudomonas spp. and TPAB changed significantly (p<0.05) during the storage process. While a significant difference was found between the MUFA levels of dorsal muscle intramuscular adipose tissue of the groups (p<0.05). As a result, it was determined that the metabolic differences of the one-way protein sources fed to the lambs in the digestive system and other organs had an effect on the meat quality, intramuscular fat and fatty acid profile of the tail.

Starch-based composite foam for chicken meat packaging

The development of compostable packages that maintain fresh meat quality, is an important achievement for the poultry industry. The objective of this study was to evaluate the feasibility of using a starch-based composite foam (SCF) in the packaging of fresh chicken meat during refrigerated storage. SCF was prepared using extrusion process. Nisin (2%) was added as antimicrobial agent (SCFN). Commercial expanded polystyrene (EPS) was used as control. Physical characterization, antimicrobial analysis and storage of fresh chicken meat were carried out. No differences were observed in SEM images between SFC and SCFN samples. Water uptake of SCF were higher than SCFN (p < 0.05). SCFN exhibited higher Young´s modulus and flexural strength (p < 0.05), and antimicrobial effect against foodborne pathogens. During the storage of chicken meat, the starch-based composite foam showed a higher capacity to retain liquid than EPS. The color of chicken meat had slight variations at day 4 compared with the raw meat. Nisin did not retard lipid oxidation of chicken meat, however, the aerobic plate count was lower. Therefore, the starch-based composite foam is suitable for fresh meat storage, being improved with the incorporation of nisin as antimicrobial agent.

Supplementary Information

The online version contains supplementary material available at 10.1007/s13197-022-05538-6.

Profile of Nitrogenous compounds and Bacterial proliferation in Rabbit meat stored cold with three types of packaging

Meat is an excellent medium for bacterial growth due to its high water and nutrient content. The nitrogenous compounds (NC) are derived through decarboxylation of amino acids due to microbial enzymes. The objective of this study was to evaluate the concentration of 3 NC and the proliferation of some microorganisms in rabbit meat with three treatments (T) , classified by three types of packaging for 21 days (d) in rabbit meat stored cold. The meat samples were obtained of the Longissimus thoracis et lumborum muscle. Each sample was divided and two groups were formed. The first group was used to measure the physicochemical characteristics of the meat, and the second group was used to quantify NC and bacterial isolation. The pH in the meat decreased from 0 to 21 d in the three T. The brightness (L*) decreased (P<0.05), while the variables a* and b* increased (P<0.05) to 21 d for all groups. Histamine and cadaverine remained low and were similar in the three T (P>0.05). Putrescine (PU) increased (P<0.05) from 7 to 21 d in the Control-Plastic (CP) and Semi-permeable plastic film (SP) groups vs. Vacuum packing (VP). The Enterobacteriaceae remained constant throughout the experimental period in the three T, compared to the aerobic mesophilic, which was higher (P<0.05) until 21 d of the evaluation in CP and SP. The type of packaging and cooling time influenced the concentration of NC. The VP had the lowest level of PU and mesophilic bacteria until 21 d of storage.

Non-Destructive Measuring Systems for the Evaluation of High Oxygen Stored Poultry: Development of Headspace Gas Composition, Sensory and Microbiological Spoilage

As poultry is known to be a perishable food, the use-by date is set in such a way that food safety is guaranteed even with a higher initial bacterial count. This means, however, that some products are wasted, even if they are still safe to eat. Therefore, non-destructive measurement devices might be a good opportunity for individual shelf-life prediction, e.g., in retail. The aim of this study was therefore to use non-destructive measurement devices based on fluorescence quenching (oxygen detection) and mid-infrared laser spectroscopy (carbon dioxide detection) for the monitoring of high-oxygen-packed poultry in different storage conditions. During 15 days of storage, the gas composition of the headspace was assessed (non-destructively and destructively), while total plate count was monitored and a comprehensive sensory evaluation was performed by a trained panel. We were able to demonstrate that in most cases, non-destructive devices have comparable precision to destructive devices. For both storage conditions, the sensory attribute slime was correlated with reaching the critical microbiological value of 107 CFU/g; the attribute buttery was also useful for the prediction of regularly stored poultry. The change in the gas atmosphere as a sign of premature spoilage, however, was only possible for samples stored in irregular conditions.

Improved microbial and sensory quality of chicken meat by treatment with lactic acid, organic acid salts and modified atmosphere packaging

Microbial contamination and growth play important roles in spoilage and quality loss of raw poultry products. We evaluated the suitability of three commercially available organic acid based antimicrobial compounds, Purac FCC80 (l-lactic acid), Verdad N6 (buffered vinegar fermentate) and Provian K (blend of potassium acetate and diacetate) to prevent growth of the innate microbiota, reduce spoilage and enhance the sensory quality of raw chicken under vacuum, high CO₂ (60/40% CO₂/N₂), and high O₂ (75/25% O₂/CO₂) modified atmosphere (MA) storage conditions. Solutions were applied warm (50 °C) or cold (4 °C) to reflect treatments prior to (Prechill) or after (Postchill) cooling of chicken carcasses, respectively. Single postchill treatments of raw chicken wings with 5% Verdad N6 or Provian K solutions and MA storage enabled complete growth inhibition during the first seven days of storage before growth resumed. Enhanced bacterial control was obtained by combining Prechill lactic acid and Postchill Verdad N6 or Provian K treatments which indicated initial reductions up to 1.1 log and where total bacterial increase after 20 days storage was limited to 1.8-2.1 log. Antibacterial effects were dependent on the concentration of the inhibiting salts used, pH and the storage conditions. Bacterial community analyses showed increased relative levels of Gram-positive bacteria and with reductions of potential spoilage organisms in samples treated with the organic acid salts Verdad N6 and Provian K. Sensory analyses of raw, treated wings showed prominent lower scores in several spoilage associated odour attributes when compared with untreated chicken wings after 13 days storage. For heat-treated chicken, only minor differences for 22 tested attributes were detected between seven antimicrobial treatments and untreated control chicken. Immersion in commercially available organic acid/salt solutions combined with MA storage can reduce bacterial levels, improve microbial and sensory quality, and potentially improve shelf life and reduce food waste of chicken products.

Evaluation of Simulated Shelf-Life Conditions for Food Service Applications on Chicken Tenderloins

The objective of this study was to validate the shelf-life of marinated and frozen chicken tenderloins. Treatments were randomly assigned to the age of the tenderloins post-harvest, days aged (DA): DA4, DA5, DA6, DA7, and DA8. Microbial analyses were used to analyze the growth of aerobic, psychotropic, and lactobacilli bacteria to assess the shelf-life of bulk-packaged chicken tenderloins. Tenderloins were sampled fresh, then vacuum tumbled in a marinade. After marination, the tenderloins were sampled with the remaining tenderloins packaged and frozen (-25 °C). After freezing the chicken tenderloins were slacked in a refrigerated cooler (2.2 °C) for up to 132 h (h) and sampled at 36 h, then every 24 h following. After marination, each treatment significantly (p < 0.05) decreased in aerobic and psychotropic counts except DA4. During slacking, no treatment crossed the threshold of 10⁶ CFU/mL (Log 6) set for this study. Though none crossed the threshold, treatments DA4, DA5, and DA6 had significant (p < 0.05) increases in aerobic bacteria after 7 days of age. The psychotropic bacteria continuously grew at each sampling period, with DA4 and DA5 surpassing the other treatments (p < 0.05) at 108 h and 132 h reaching 105 CFU/mL. Every treatment remained below the spoilage threshold, suggesting that this method of storage is suitable for chicken tenderloin shelf-life.

Effect of the homogenization technique on the enumeration of psychrotrophic bacteria in food absorbent pads

Four methods were tested for enumerating bacteria present in the absorbent pads (AP) used in packaging chicken and other meats. Viable counts were ascertained at day 0 and day 7 (d0 and d7, respectively). Sampling bacterial cells from AP were carried out using a countertop blender, Stomacher, sonication, and blender in combination to sonication. The release of bacterial cells by breaking down the AP with the blender resulted in the highest CFU counts. At d0, a bacterial recovery rate of 94% was obtained with the blender, while the recovery rates using Stomacher or sonication alone were 58% and 73%, respectively. At d7, the Stomacher treatment also gave the lowest colony forming unit (CFU) values in the AP incubated at 7 °C. Sonication of the AP prior to homogenization with the blender did not increase CFU counts. Results suggested that breaking down the AP with a blender gives higher CFU levels than the Stomacher, which is the most commonly used technique for this purpose.

Effect of Decontamination Treatments on Campylobacter jejuni in Chicken

The ability of different decontaminating treatments (acetic, citric and fumaric acids, and potassium sorbate) to decrease Campylobacter jejuni on chicken legs was evaluated. Fresh chicken legs were inoculated with C. jejuni and washed with either acetic, citric, or fumaric acid (1% and 2%), or potassium sorbate (1%, 2%, and 5%) solutions or distilled water. Evolution of C. jejuni, Pseudomonas, and Enterobacterales counts, and sensorial acceptability were evaluated after treatment (day 1) and on days 2, 4, 7, and 9 of storage at 4 °C. The lowest Pseudomonas counts were found in those legs dipped in 2% fumaric acid, while the lowest Enterobacterales populations were found in those legs dipped in 2% fumaric or 2% acetic acid. The shelf life of the legs treated was widened by at least 2 days over the control legs. The highest C. jejuni reductions after treatment were obtained in samples dipped in 2% citric acid, which were approximately 2.66 log units lower than in non-treated legs. However, the efficacy of citric acid decreased during storage. After day 2 of storage, the highest reductions of C. jejuni were found in those legs dipped in 2% acetic acid.

Insights into the Identification of the Specific Spoilage Organisms in Chicken Meat

Poultry meat deterioration is caused by environmental conditions, as well as proliferation of different bacterial groups, and their interactions. It has been proposed that meat spoilage involves two bacterial groups: one group that initiates the deterioration process, known as specific spoilage organisms (SSOs), and the other known as spoilage associated organisms (SAOs) which represents all bacteria groups recovered from meat samples before, during, and after the spoilage process. Numerous studies have characterized the diversity of chicken meat SAOs; nonetheless, the identification of the SSOs remains a long-standing question. Based on recent genomic studies, it is suggested that the SSOs should possess an extensive genome size to survive and proliferate in raw meat, a cold, complex, and hostile environment. To evaluate this hypothesis, we performed comparative genomic analyses in members of the meat microbiota to identify microorganisms with extensive genome size and ability to cause chicken meat spoilage. Our studies show that members of the Pseudomonadaceae family have evolved numerous biological features such as large genomic size, slow-growing potential, low 16S rRNA copy number, psychrotrophic, and oligotrophic metabolism to initiate the spoilage of poultry meat. Moreover, inoculation experiments corroborated that these biological traits are associated with the potential to cause chicken meat deterioration. Together, these results provide new insights into the identification of SSO. Further studies are in progress to elucidate the impact of the SSO on meat quality and microbiota diversity.

Impact of egg disinfection of hatching eggs on the eggshell microbiome and bacterial load

Disinfection of hatching eggs is essential to ensure high quality production of broilers. Different protocols are followed in different hatcheries; however, only limited scientific evidence on how the disinfection procedures impact the microbiome is available. The aim of the present study was to characterize the microbiome and aerobic bacterial load of hatching eggs before disinfection and during the subsequent disinfection steps. The study included a group of visibly clean and a group of visibly dirty eggs. For dirty eggs, an initial wash in chlorine was performed, hereafter all eggs were submitted to two times fumigation and finally spray disinfection. The eggshell microbiome was characterized by sequencing of the total amount of 16S rRNA extracted from each sample, consisting of shell surface swabs of five eggs from the same group. In addition, the number of colony forming units (cfu) under aerobic conditions was established for each disinfection step. The disinfection procedure reduced the bacterial load from more than 104 cfu (initially visibly clean eggs) and 105 cfu (initially visibly dirty eggs) to less than 10 cfu per sample after disinfection for both groups of eggs. The microbiome of both initially visibly clean and initially visibly dirty eggs had the highest abundances of the phyla Firmicutes, Proteobacteria and Bacteroidetes. Within the phyla Firmicutes the relative abundances of Clostridiales decreased while Lactobacillus increased from before to after final disinfection. In conclusion, the investigated disinfection procedure is effective in reducing the bacterial load, and by adding a chlorine wash for initially visibly dirty eggs, the microbiome of initially visibly clean and initially visibly dirty eggs had a highly similar microflora after the final disinfection step.

Meat quality of heat stress exposed broilers and effect of protein and vitamin E

1. This study was designed to determine the effects of heat stress exposure on broiler fattening performance, meat quality and microbial counts. 2. Six groups were established: CHP (24°C+210 g/kg crude protein (CP)), SHP (34°C+210 g/kg CP), CLP (24°C+190 g/kg CP), SLP (34°C+190 g/kg CP), SHPVE (34°C+210 g/kg CP+Vitamin E) and SLPVE (34°C+190 g/kg CP+Vitamin E) groups. 3. It was determined that the body weights of the male animals included in Group CHP displayed statistically significant differences in comparison to those of Groups SHP, CLP and SLP. Furthermore, it was ascertained that the values of Group CLP also displayed statistically significant differences in comparison to those of Groups CHP, SHP and SLP. The feed consumptions in Groups CHP and CLP were significantly different from those of the remaining groups, excluding Group SHP. The highest feed conversion rate was determined in Group SHPVE. 4. When evaluated for chicken drumstick TBA values, Group CHP differed significantly from Groups SHP, SHPVE, CLP and SLP, whilst Group CLP differed significantly from Groups SHP, SHPVE and SLP. On the other hand, when evaluated for breast meat TBA values, Group CHP displayed statistically significant differences in comparison to Groups SHP, SLP and SLPVE, whilst Group CLP differed significantly from Groups CHP, SHP, SLP and SLPVE. 5. The sensitivity of breast meat to colour susceptibility was greater than that of chicken drumsticks. While storage period affected the TBA values and microbial counts of meat significantly, its effect on colour parameters was found to be variable. Trial groups significantly affected total aerobic mesophilic bacteria counts in chicken drumsticks, and Enterobacteriaceae and total aerobic mesophilic bacteria counts in breast meat. 6. In conclusion, heat stress adversely affected final body weights and the lipid oxidation of meat, whilst vitamin E alleviated these adverse effects.