Aerobic Mesophilic Bacteria Counts Research Articles

Toplu Yemek Üretimi Yapan Bir İşletmede Personel ve Gıda Temas Yüzeylerinin Mikrobiyolojik Yönden Değerlendirilmesi

Bu çalışmada, Kayseri ilinde bir kamu kuruluşuna ait toplu yemek üretimi yapan bir tesiste yemek hazırlamada çalışan personel ve gıda ile temas eden yüzeylerden alınan örneklerin bazı indikatör mikroorganizmaların varlığı açı- sından incelenmesi amaçlandı. Çalışma süresince tesis Nisan-Temmuz 2021 tarihleri arasında birer ay arayla dört kere ziyaret edildi. Her ziyarette tesiste yemek hazırlamada çalışan 24 personel ile 16 adet ekipman ve gıda ile temas eden yüzeylerden (bıçak, köfte şekillendirme makinesi, kıyma makinesi, et doğrama makinesi, sebze doğrama makinesi ve tezgâh) alınan svap örnekleri materyal olarak kullanıldı. Alınan örnekler toplam aerobik mezofilik bakteri (TAMB) sayımı ile koliform, Escherichia coli (E. coli) ve Staphylococcus aureus (S. aureus) kontaminasyon durumu bakımından kon- vansiyonel metotlar kullanılarak analiz edildi. Çalışmada, analiz edilen personel el svap örneklerinin %6.6, %3.3 ve % 4.4’ü sırası ile S. aureus, E. coli ve total koliform ile kontamine olduğu belirlendi. Tesiste yemeklerin hazırlık aşamala- rında çiğ gıda ile temasta olan yüzey örneklerinin tamamının total koliform ve E. coli, %96.8’inin ise S. aureus ile konta- mine olduğu tespit edildi. Çalışma sonuçları, Kayseri ilinde bir kamu kuruluşunda toplu gıda üretimi yapılan tesiste çalı- şan personelin büyük çoğunluğunun el hijyeni kurallarına uyduğunu fakat yemek hazırlama aşamalarında kullanılan ekipman ve yüzeylerin sanitasyonunun yetersiz olduğunu ve çapraz kontaminasyon riski taşıdığını gösterdi.

Microbial inactivation and quality impact assessment of red pepper paste treated by high pressure processing

The study aimed to investigate inactivation of naturally occurring microorganisms and quality of red pepper paste treated by high pressure processing (HPP). Central composite rotatable design was employed to determine the impacts of pressure (100–600 MPa) and holding time (30–600 s). HPP at 527 MPa for 517 s reduced aerobic mesophilic bacteria count by 4.5 log CFU/g. Yeasts and molds counts were reduced to 1 log CFU/g at 600 MPa for 315 s. Total phenols, carotenoids and antioxidants activity ranged from 0.28 to 0.33 g GAE/100 g, 96.0–98.4 mg βc/100 g and 8.70–8.95 μmol TE/g, respectively. Increase (2.5–6.7%) in these variables was observed with increasing pressure and holding time. Total color difference (ΔE∗) values (0.2–2.8) were within the ranges of ‘imperceptible’ to ‘noticeable’. Experimental results were fitted satisfactorily into quadratic model with higher R2 values (0.8619–0.9863). Optimization process suggested treatment of red pepper paste at 536 MPa for 125 s for maximum desirability (0.622). Validation experiments confirmed comparable percentage of relative errors. Overall, this technique could be considered as an efficient treatment for the inactivation of microorganisms that naturally occur in red pepper paste with minimal changes in its characteristics.

Microbial Growth Dynamics in Minced Meat Enriched with Plant Powders

Plant powders with antimicrobial properties can be used in food manufacturing and must comply with the demands of consumers regarding microbiological safety, nutritional value, and sensory properties of foods. The present study aimed to assess the microbial growth inhibitory ability of different plant powders, including by-products of horticultural primary processing (e.g., pomace) in raw and cooked minced pork. The total counts of aerobic mesophilic bacteria, pseudomonads, yeasts, and moulds were studied to assess the microbial growth dynamics in meat samples. Additionally, for the plant powders, which were able to suppress the microbial growth in a total counts dynamics study, the growth potential of Listeria monocytogenes in ready-to-eat (RTE) minced meat samples was estimated by challenge testing. The results showed that the most effective combinations of plant powders in raw minced pork, in relation to the total counts of microorganisms, were 3% apple+1% onion+2% blackcurrant berries (Apple+On+BCber); 3% apple+1% garlic+2% tomato (Apple+Ga+Tom); and 3% apple+2% tomato+1% rhubarb petioles (Apple+Tom+Rhub). However, challenge tests revealed that some plant powders were unable to inhibit the growth of L. monocytogenes. The lowest L. monocytogenes growth potential (δ = 2.74 log cfu/g) was determined for cooked minced pork samples enriched with 2% rhubarb petioles, followed by Apple+On+BCber (δ = 3.63 log cfu/g) and Apple+Tom+Rhub (δ = 3.74 log cfu/g). In minced pork samples without plant additives, the L. monocytogenes growth potential was 7.30 log cfu/g. In conclusion, blends of plant powders may have good potential for developing meat products with acceptable microbiological quality.

Determination of hygienic conditions of home kitchen sponges in Manisa, Turkiye

It is known that sponges remove the food residues from the utensils, sinks and equipment used at home kitchens. Porous kitchen sponges provide the perfect physical place for a bacterial community in this study, it was aimed to determine the hygienic conditions of sponges used in home kitchens in Manisa, Turkey. Samples were collected from 100 different addresses in Manisa city center. Results of the microbiological analysis showed that, the average total mesophilic aerobic bacteria count of samples was 6.42 log cfu/sponge, whereas total coliform and total yeast and mold counts of the samples were 1.63 log cfu/sponge and 2.12 log cfu/g respectively. Staphylococcus aureus, Salmonella spp. and Escherichia coli O157:H7 were not detected in any of the samples. The data obtained in this study supports the previous findings of other researchers that kitchen sponges provide a hospitable environment for microorganisms.

Electrospun eugenol-loaded gelatin nanofibers as bioactive packaging materials to preserve quality characteristics of beef

In this study, electrospinning technique was employed to fabricate eugenol loaded gelatin nanofibers (ELGNs) by using gelatin as an active material to encapsulate eugenol. The results indicated that eugenol could be successfully encapsulated within nanofibers, as verified by SEM, FTIR, and zeta potential analyses. The average zeta potential value of ELGNs was determined to be − 15.08 mV. The average diameter of gelatin nanofibers was enlarged with eugenol encapsulation, increasing to diameter of 125 nm. ELGNs had a smooth and uniform fiber morphology observed by SEM. The ELGNs demonstrated a potent antibacterial activity by significant (P < 0.05) reduction in the number of total mesophilic aerobic bacteria counts by 1.62 log and psychrophilic aerobic bacteria counts by 1.33 log in fresh beef samples treated with ELGNs. Moreover, the bioactive ELGNs maintained textural properties (hardness–4.75 N, gumminess–1.75 N, and chewiness–3.87 N × mm at 9th day of storage) and sensory properties, exhibiting advantages as antimicrobial packaging materials that maintained the quality and freshness of the raw meat, along with the extension of its shelf life to 9 days. Significant (P < 0.05; 0.01) negative and positive correlations were found among the microbiological, textural, and sensory parameters, which explained and confirmed the reason for the effectiveness of the nanofiber treatment. In conclusion, our results suggested that the electrospinning approach in this study could be an effective technique to encapsulate eugenol within gelatin nanofibers and the electrospun ELGN mats could be a novel bio-degradable active packaging material with good antibacterial effects.

Characterization of pasteurized and sonicated whole shell egg and evaluating egg's interior quality during storage period

AbstractThis study aims to investigate the effects of processing technologies (pasteurization; 56.5 °C for 45 min and sonication; 250 W for 5 min) on the whole eggshell. The interior quality and physicochemical parameters of eggs such, weight loss, foaming properties, total mesophilic aerobic bacteria count, and rheological behavior were evaluated during storage at ambient temperature for six weeks. Sonication has improved the physico‐chemical properties of the egg samples and enhanced the functionality. The weight losses of all treatment and control groups increased during the storage period. The greatest weight loss was detected in the control sample (9.5%). Weight loss between ultrasound (6.7%) and pasteurization (7.9%) groups were similar (p &gt; 0.05). The storage period had a significant (p &lt; 0.05) effect on the internal attributes of eggs such as functional characteristic (foaming ability). We conclude that the sonication has a promising advantage in techno‐functional properties comparing to thermal pasteurization.Practical applicationConsumer perception decreases to thermally processed foods. Traditional heat treatment processing such as pasteurization can adversely impact the functional properties, sensory, color, and nutritional values of processed eggs. However, nonthermally processing techniques applied at lower temperatures may cause limited detrimental effects on egg quality and prepared products from eggs such as meringue, cake, and mayonnaise. The eggs treated with emerging methods such as ultrasound retained egg's functional attributes and had their shelf life increased such as foaming ability and gelling properties. Also, sonication has promising potential for industrial application on shell eggs during storage and therefore hold potential for their shelf‐life extension and improve the functionality of final baked product. The treatment with emerging methods such as ultrasound retained egg's functional attributes and had their shelf life increased while enhancing the functional properties.

Erzurum Piyasasında Tüketime Sunulan Mahalli ve Endüstriyel Dondurmaların Bazı Mikrobiyolojik ve Fizikokimyasal Özelliklerinin Karşılaştırılması

In this research, a total of 20 plain ice-cream samples, including 10 local and 10 industrial plain ice-cream samples presented for consumption in Erzurum province, were collected from the market and microbiological, physical and chemical analyzes were carried out on these samples. As a result of the microbiological analyzes, the average total aerobic mesophilic bacteria count (TAMB), yeast and mould count, number and group of coliform bacteria count in local ice cream samples have been calculated as 5.89 log cfu/g, 4.22 log cfu/g and 2.26 log cfu/g, respectively. Identical analyzes have also been performed for industrial ice-cream samples, and all data mentioned for local samples have been calculated. These values are determined as 4.72 log cfu/g,

Farklı Çiftliklerden Elde Edilen Keçi Sütlerinde Sütün Bileşimi ve Mikrobiyolojik Özelliklerinin Belirlenmesi

Goat milk has a great importance for human nutrition considering its nutrient content. In addition, the demand for goat milk and products derived from goat milk has increased in recent years. However, the microbiological properties of milk can directly affect human health. In this study, it was aimed to determine the nutrient content and some microbiological properties of goat milk obtained from different farms. In the study, hand milking farms were determined. After milking, a sufficient amount of milk sample was taken and brought to the laboratory at +4°C. In the milk samples, the composition of the milk, the total number of aerobic mesophilic bacteria, the number of yeast-mold and coliform bacteria were determined. The highest protein, lactose and solids ratio (%) was obtained in milk samples taken from farms 2 and 4. The highest fat content in milk was determined in the sample taken from farm 4. It was observed that the milks of farms 2, 3 and 4 had similar mineral substance amounts. Total aerobic mesophilic bacteria (PCA) count (191×104), yeast-mold (PDA) count (42×103) and coliform bacteria (VRBA) count (710×102) were determined in farm 2. As a result, in terms of some milk components were determined statistical differences between farms. The main difference is in terms of milk hygiene. However, it was determined that the milk showed significant changes in terms of microbiological properties according to the farms from which they were obtained. It can also be said that these changes may affect the health of people who directly or indirectly consume these milks.

Determination of Elemental Contents and Microbiological and Chemical Properties of Çökelek Cheeses Consumed in Turkey.

The Çökelek samples what 30 different were collected from randomly local bazaars to investigate heavy metal contaminant and mineral levels and some physicochemical and microbiological properties of samples. While the Pb was identified in 6 of the 30 samples, the As was only found in 4 of the samples. The mean major and trace element contents of Çökelek samples were ordered as Na > P > Ca > K > Mg and Al > Zn > Ni > Cu, respectively. The physicochemical properties indicated a high deviation among samples. The mean total solids, ash, salt, fat, protein waters soluble nitrogen contents, and sample ripening index were 29.83%, 1.88%, 0.68%, 4.31%, 19.84%, 0.33%, and 1.79%, respectively. The mean total aerobic mesophilic bacteria (TAMB) count of Çökelek samples was found as 8.26 log CFU g-1. The coliform bacteria and yeast-mold counts were detected in 11 and 27 of 30 samples, respectively. The mean coliform and yeast-mold counts were 1.82 log CFU g-1 and 7.11 log CFU g-1, respectively. Traditional cheeses are not mentioned in legal laws such as the Turkish Food Codex. So, there is no legal limit and standard production processes. This situation is a problem in terms of traditional cheese quality. For this reason, traditional cheese should perform further studied, and determine the legal limits.

Combination of cassava starch biopolymer and essential oils for coating table eggs

This work aimed to evaluate the eggshell microbiota and the internal egg quality after coatings with cassava starch biopolymer enriched with different essential oils during 35 days of storage at 20°C. A total of 369 brown table eggs were used and distributed in the following treatments: uncoated eggs, coated with cassava starch + Ginger essential oil (CS+GIN), cassava starch + Lemongrass essential oil (CS+LEM), and cassava starch + Tahiti lemon essential oil (CS+TAH). The count of total aerobic mesophilic bacteria on coated eggshells at 0 and 35 days of storage were similar to each other (mean 0.70 ± 0.37 and 0.91 ± 0.22 log10 CFU/mL) and significantly lower compared to uncoated eggs (2.21 ± 0.17 and 3.17 ± 0.22 log10 CFU/mL), in that order. On the 35th day, coated eggs showed similar Haugh unit (HU) values between them (mean 70.61 ± 5.35; classified as A - high quality) and significantly higher than uncoated eggs (51.60 ± 4.28; classified as B - average quality). Cassava starch coatings added with essential oils preserved the internal quality of the eggs during storage for 5 weeks at 20°C, reducing the eggshell microbiota and effectively keeping it at low levels during storage.

Diversity in smallholder dairy production systems in the Brazilian semiarid region: Farm typologies and characteristics of raw milk and water used in milking

Smallholder dairy farms (SDF) producers are being challenged by market demands combined with competition and limited access to productive and market inputs, contributing for reducing its participation in the dairy activity. Thus a sustainability assessment for SDF development is necessary, opening the opportunity for recognizing the diversity between production systems. Farm typologies are often used for this purpose. The objective was to develop a typological analysis of the smallholder dairy farms in the Brazilian semiarid region and evaluate characteristics of raw milk and water used in milking. A semi-structured questionnaire containing social, physical, livestock, herd management, technological, productive, and economic indicators with 49 variables was applied in 28 SDF. Of these, 23 were selected, and collections of milk and water used for milking management were performed. Three multivariate analysis techniques were used: exploratory factor analysis, hierarchical cluster analysis, and canonical discriminant analysis. Three production systems have been identified: Conventional system: Mature illiterate and rural farmers, small herds and farms, low technological level, less intensive management, and low milk production with in nature marketing (15 farms; 53.6%); Traditional system: Mature farmers with basic education, farms managed with hired labor, large herds and areas, extensive management, low technological level, high production of milk for the manufacture of cheese (6 farms; 21.43%); and Emerging system: Young farmers with a high level of education, small herds and farms, intensive management, intermediate technological level, and high milk production and productivity with in nature marketing (7 farms; 25.0%). The social, physical, livestock, herd management and technological, and productive indicators showed discriminatory power (P < 0.05) to differentiate the typologies. Milk and water traits were similar (P > 0.05) among the production systems. The average values of the milk composition are in the threshold of the Brazilian legislation, unlike the somatic cell count (CSS) and standard plate count (SPC). Antibiotic residue was not found in milk from any SDF.The water used in milking management was characterized by high counts of aerobic mesophilic bacteria and total and thermotolerant coliforms, hard water, and neutral pH. For the continuity of SDF in the Brazilian semiarid, it is essential (i) participation of young people in the sector; (ii) feed planning for the dry period; (iii) herd health calendar according to legislation; (iv) water treatment (chlorination) and use of alkaline detergent for use in milking management, and (v) formal marketing of milk and its derivatives. Finally, our results can be used to inform and support public decision-makers responsible for the formulation and implementation of livestock development policy in the Brazilian semiarid region and being useful for other drylands.

Determination of antilisterial effect of some microbial isolates from traditional zlatar cheese during the fermentation of soft white cheese.

The aim of this study was to select autochthonous lactic acid bacteria (LAB) isolates with antilisterial activity from Zlatar cheese and to evaluate the ability of selected LAB to control Listeria monocytogenes growth during soft white cheese production. The genotype characterization of isolated LAB (n = 93) was done using PCR method by 16S rRNA sequencing. In this way, the following isolates were detected: Lactococcus lactis ssp. lactis (40 isolates), Enterococcus faecalis (30), Lactobacillus plantarum (12), Leuconostoc mesenteroides ssp. mesenteroides (3) Lactobacillus garvieae (3), Lactobacillus curvatus (2), Lactobacillus casei (1), Enterococcus faecium (1) and Staphylococcus hominis (1). Each isolated LAB was tested for bacteriocin-producing ability. It was determined that two LAB isolates had bactericidal properties: Lactococcus lactis ssp. lactis SRB/ZS/094 and Enterococcus faecalis SRB/ZS/090. Semi-purified of enterococcal bacteriocin (enterocin) was isolated using precipitation procedures with ammonium sulphate. Its properties were determined (strength and range of activities). Isolated enterocin and bacteriocin-producing Lactococcus strain showed significant antimicribial activity against Listeria monocytogenes, but still the inhibition activity of Staphylococcus aurues and Escherichia coli was not detected. Based on the obtained laboratory results, in the second phase of the research, the antilisterial effect of bacteriocin isolated from Enterococcus faecalis SRB/ZS/090 and cells Lactococcus lactis ssp. lactis SRB/ZS/094 were determined, that are added as additives in the production of soft white cheese through five variants. Cheese supplemented with enterocin (E2) had the lowest aerobic mesophilic bacteria count, indicating that enterocin (E2) play an important role for bio-preservation.

Effect of moderate intensity pulsed electric field on shelf-life of chicken breast meat

ABSTRACT 1. Moderate intensity pulsed electric field (MIPEF) is a fairly new research topic for microbial inactivation on muscle foods. In this study, indirect application of MIPEF (2.5 kV/cm, 4.67 kV/cm, 7 kV/cm) was evaluated in terms of the growth of some pathogenic bacteria and the quality characteristics of chicken breast meat during cold storage (4°C). 2. This study was conducted in two stages. In the first stage, pure cultures of S. enteritidis, P. aeruginosa, S. aureus, L. monocytogenes, E. coli and C. jejuni were inoculated in broth and stored in a refrigerator at 4°C under MIPEF. Both E. coli and C. jejuni showed a remarkable resistance to MIPEF under 4.67 kV/cm and 7 kV/cm, respectively. 3. In the second stage, MIPEF was applied to packaged chicken breast samples. The limit for total mesophilic aerobic bacteria (TMAB) count was exceeded in 4.67 and 7 kV/cm applied groups 2 d later than seen in the control group (C). Almost 2 log differences were determined for total coliform bacteria in 4.67 and 7 kV/cm applied groups as compared to C (P < 0.05). Inoculated P. aeruginosa count remained the same, whereas L. monocytogenes growth was promoted by 4.67 kV/cm (P < 0.05). 4. pH value, CIE L*, b*, C* colour values of chicken breast fillets were not affected by MIPEF application while ΔE values showed the maximum change in the C group. 5. This study demonstrated that improved shelf-life of chicken breast fillets was provided by moderate intensity DC-pulses in combination with cold storage.

MICROBIOLOGICAL QUALITY AND SAFETY ASSESSMENT OF (SOBIA) A TRADITIONALLY FERMENTED BEVERAGE OF WESTERN SAUDI ARABIA

Sobia is a traditional fermented beverage that is well known in the western province of Saudi Arabia particularly during Ramadhan season. The beverage is sold by retailers as well as by anonymous street vendors. We aimed to examine the microbiological qualities of sobia and provide a safety assessment of its consumption. Total counts of aerobic mesophilic bacteria were performed on plate count agar, determination of staphylococci count was carried on mannitol salt agar, while quantitative determination of coliforms and thermotolerant coliforms was carried out by most probable number (MPN) method, antimicrobial susceptibility testing was carried out by means of disc diffusion method on Mueller-Hinton agar. All sobia samples (P &lt;0.001) obtained from anonymous street vendors or low profile retailers were found to be in an unsatisfactory microbiological quality. Escherichia coli, Cronobacter sakazakii, Enterobacter cloacae and Klebsiella pneumoniae were predominant than other coliforms genera. Although the majority of these species (P &lt;0.001, x2) were not exhibiting multidrug resistance, the consumption of sobia samples sold on the street by anonymous vendors may pose significant public health risk and therefore it should be avoided.

The use of microfiltration technique in the production of skim milk powder: The effect of milk transport conditions on the microbiological and physicochemical properties of milk and milk powders

The aim of this work was to study the effect of milk transport conditions and microfiltration (MF) treatment on the physicochemical and microbiological properties of milk and skim milk powder (SMP). The raw milk was determined as milk after milking (30–35°C), uncooled inner‐city milk (3 h at 20–25°C), cooled transport milk (12 h at 4–6°C) and the control milk (cooling to 4°C as soon as milking; non‐MF). SMP samples were produced from MF‐treated milk with membrane pore sizes of 0.5‐μm and 0.8‐μm. MF application provided up to 2.39, 1.27, 1.64 and 1.67 log reductions in counts of total aerobic mesophilic bacteria, yeast–moulds, Bacillus and Pseudomonas species in milk, respectively. MF treatment of milk improved the microbiological quality without any significant change in the chemical composition of SMPs.

Prevalence, Biofilm Formation, and Antimicrobial Resistance of Escherichia coli, Staphylococcus aureus, and Salmonella Isolates from Goat Meat Marketed in Petrolina, Brazil

The aim of this study was to evaluate the prevalence and antibacterial resistance and biofilm formation by bacterial strains isolated from raw goat meat sold in street fairs (SF) and commercial establishments (CE) in Petrolina, Pernambuco, Brazil. SF samples had mesophilic aerobic bacteria counts of 3.71 to 7.57 log CFU/g, S. aureus counts of 1.78 to 5.38 log CFU/g, total coliform counts of 2.3 × 101 to &gt;1.1 × 103 most probable number (MPN)/g, thermotolerant coliform counts of &lt;3.0 to &gt;1.1 × 103 MPN/g, and Escherichia coli counts of &lt;3.0 to &gt;1.1 × 103 MPN/g. CE samples had mesophilic aerobic bacteria counts of 2.90 to 6.00 CFU/g, S. aureus counts of 2.00 to 4.49 log CFU/g, total coliform counts of 2.3 × 101 to &gt;1.1 × 103 MPN/g, thermotolerant coliform counts of 3.0 to &gt;1.1 × 103 MPN/g, and E. coli counts of &lt;3.0 to &gt;1.1 × 103 MPN/g. Salmonella was detected in 25% of SF and CE samples. All isolates of S. aureus and Salmonella and 95.6% of E. coli isolates were biofilm producers. Resistance to multiple drugs was found in isolates of Salmonella, E. coli, and S. aureus from SF and CE samples. Goat meat marketed in Petrolina is heavily contaminated with pathogenic bacteria resistant to multiple drugs and capable of biofilm formation.

Use of riboflavin to reduce decay and extend the shelf-life of fresh-cut sweet pepper

Riboflavin (vitamin B2) generally is recognized as a safe (GRAS) additive. It is used in food to fortify products with low natural content or compensate for the possible vitamin losses during processing. In this work, we studied the effect of pre-storage riboflavin dips on the quality maintenance of fresh-cut pepper (Capsicum annum L). We initially tested the efficacy of different riboflavin concentrations (0, control; 1; 10 and 100 μmol L−1) to reduce spoilage in fresh-cut green sweet pepper sticks (5 × 1 cm). Treatments with 100 μmol L−1 riboflavin effectively controlled pepper spoilage and were therefore selected for further evaluation along with refrigerated storage. Riboflavin dips reduced soft-rot decay incidence and severity and prevented the increase in electrolyte leakage, and respiration during storage. Riboflavin treatments preserved textural properties by preventing tissue hardness, stiffness, and resistance to bend losses. Treated peppers also presented lower yeasts and molds and aerobic mesophilic bacteria counts. Finally, riboflavin-dips improved antioxidant and phenolics retention without alterations in color, weight loss, sugar, or organic acids. Taken together, results show, for the first time, that riboflavin may be used as a postharvest preservative agent to extend the shelf-life of fresh-cut vegetables.

Inhibition of E. coli and bio-preservation of ground beef by Lactobacillus, black pepper extract and EDTA

The objectives of present study were to evaluate the potential of Lactobacillus reuteri or Lactobacillus casei combined with black pepper extract (BPE) and ethylenediamine tetraacetic acid (EDTA) for controlling the growth of E. coli O157:H7 and improving the chemical, microbiological and sensory quality of ground beef stored at 10 °C for 12 days. The in vitro results indicated that the combination of L. casei with BPE and EDTA had the most potent antibacterial effect against E. coli and resulted in 2.7 log CFU/ml reduction. In ground beef, the combination of L. reuteri or L. casei with BPE and EDTA decreased E. coli and aerobic mesophilic bacteria counts up to 1 and 1.6 log CFU/g, respectively. Meanwhile, this combination significantly reduced the lipid oxidation rate (up to 60%) and improved odor and overall acceptability scores of ground beef. It was concluded that the combination of L. casei with BPE and EDTA could be used in ground beef to control microbial proliferation, retard lipid oxidation, and improve sensory quality.

Characterization of lactic acid bacteria postbiotics, evaluation in-vitro antibacterial effect, microbial and chemical quality on chicken drumsticks

The aims of this study were to characterize postbiotics, and to evaluate their antibacterial effects in-vitro and on chicken drumsticks. Postbiotics [Pediococcus. acidilactici (PA), Latilactobacillus sakei/Staphylococcus xylosus (LS)] exhibited strong antioxidant activity, and their total phenolic contents were found as 2952.78 ± 0.4 and 1819.44 ± 0.39 mg GAE/L, respectively (P < 0.05). A total of 19 different phenolic and flavonoids were determined in the postbiotics. The results of the study revealed that 5% and 10% postbiotics + EDTA decreased the number of L. monocytogenes nearly 5.0 log10 in 6 h in TSB. S. Typhimurium count in the chicken drumstick decontaminated with 10% PA was found as 2.1 log10 lower than the control group on day 0. L. monocytogenes counts in the chicken drumstick decontaminated with 10% Postbiotics+1% LA groups were found to be 1.1 log10 lower than the control group (P < 0.05). The lowest total mesophilic aerobic bacteria counts in the chicken drumsticks were found in the 10% Postbiotics+1% LA samples, and postbiotics did not change the color properties of the drumstick samples on day 0 (P > 0.05). In conclusion, postbiotics and their combinations with natural preservatives may be an alternative approach to reduce the food-borne pathogens and to extend the shelf-life of poultry meat and meat products.

The influence of laurel essential oil treatment on the shelf-life and sensory characteristics of fresh-cut apples during storage

Fresh-cut apples provide consumers convenient, fresh, ready-to-eat product. However such products are susceptible to browning and microbiological spoilage which occurs very quickly after processing. Due to their antimicrobial properties, essential oils have a potential stabilizing effect on fresh-cut products, but could have undesirable effects on their color or taste. The aim of this study was to investigate the effect of laurel essential oil (LEO) treatment at different concentrations (25, 75, 125 and 175 mg L-1) on the shelf-life (aerobic mesophilic bacteria count) and physical (soluble dry metter, pH, color, texture) and sensory characteristics of fresh-cut apples during 10 days of storage at 8 °C. Number of aerobic mesophilic bacteria decreased with the increase of LEO concentration and it slightly increased with the increase of storage time. In general, samples treated with 75 mg L-1 LEO had the lowest and samples treated with 175 mg L-1 LEO the highest soluble dry matter, while pH trend was vice versa. Soluble dry matter, pH, and firmness increased during storage. Apples treated with 75 mg L-1 LEO after 10 days of storage showed the least color change. This study showed that LEO can be used to preserve and enrich sensory characteristics of fresh-cut apples, especially at a concentration of 75 mg L-1. Generally, this LEO concentration can be recommended regarding the results of microbiological and sensory analysis as well as results of soluble dry matter, pH, color parameters and firmness.