Psychrophilic Bacteria Counts Research Articles

High-pressure processing for pickled crabs: Safety, quality and flavor assessment and correlation analysis of spoilage indicators

Pickled aquatic products are often susceptible to spoilage, which can significantly affect their edibility and flavor. This study aimed to improve the safety and quality aspects of pickled crabs by treated with high-pressure processing (HPP, 400 MPa for 5 min). The physical, chemical, microbiological, and flavor properties of the crabs before and after HPP were assessed, correlation and cluster analysis and orthogonal partial least squares discriminant analysis (OPLS-DA) were conducted on specific indicators influencing crab spoilage. The results indicated that HPP effectively reduced the total viable count, psychrophilic bacteria count (PBC), and Escherichia coliform (E. coli) count during storage at 4 °C (reduced by 30.61%, 36.72%, 100%, day 0, respectively; 19.02%, 21.95%, 100%, day 42, respectively). Moreover, HPP treatment reduced the total volatile basic nitrogen (TVBN) content (35.33 mg/100 g to 31.81 mg/100 g) and the production of putrescine (1858.7 mg/kg to 1293.04 mg/kg) and cadaverine (753.47 mg/kg to 422.08 mg/kg) in the end of storage stage, which extend the shelf life of the pickled crab by 12 days. Furthermore, the application of HPP facilitated the penetration of ethanol into the crab meat, thereby enhancing the development of the characteristic pickled crab flavor. The OPLS-DA analyses indicated that TVBN, TBA, and histamine as deteriorative factors for quality deterioration are key factors determining spoilage of crab, which are significantly correlated with other corruption products. This study provides valuable insights into improving the safety and flavor of crab products, establishing a theoretical basis for ensuring quality control throughout the production process.

INVESTIGATION OF USAGE OPPORTUNITIES OF DIFFERENT PROPORTIONS OF WHEY AND CHIA SEED FLOUR IN BUTTERMILK

In this study, it was aimed to obtain a functional beverage with high nutritional value by using whey and chia seed flour in the production of buttermilk. In addition to its high nutritional value, while preventing whey from causing environmental pollution as a waste material, it is aimed to obtain a new dietary product with chia seed flour containing 34-40g fiber per 100g, antioxidant, omega-3 fatty acid and rich protein content. Experimental buttermilk samples were prepared by adding whey (PAS) and chia seed flour at different rates. K (control group), K2 (%1 Chia seed meal), K3 (%0,5 Chia seed meal), Group 1 (25% Whey + %1 Chia seed meal), Group 2 (25% Whey + %0,5 Chia seed meal), 3. Group (50% Whey + %1 Chia seed meal), 4.Experimental groups prepared as a group (50% Whey + %0,5 Chia seed flour) were kept at +4 ̊C and their physical, chemical and sensory properties were examined on the 1st, 3rd, 5th, 7th and 14th days. In the experimental buttermilk samples we researched, the use of whey and chia seed flour was found to have a significant effect on psychrophilic bacteria count (log cfu/ml), coliform group bacteria (log cfu/ml), yeast-mold count (log cfu/ml), lactobacil spp. (log cfu/ml) and lactococ spp. (log cfu/ml), pH, acidity (lactic acid), water-soluble dry matter (%), serum separation (%), color values (L*, a*, b*) and sensory properties (p

Evaluation of dietary supplementation of garlic powder (Allium sativum) on the growth performance, carcass traits and meat quality of Japanese quails (Coturnix coturnix japonica)

Dietary supplementation with plant-based products may arise as part of an alternative strategy to using antibiotics as growth promoters in the poultry industry. Garlic powder (GP) possesses antimicrobial and antioxidant properties. The aim was to investigate the effect of dietary supplementation of GP on growth performance, carcass traits and meat quality of the Japanese quail. A total of 240, day-old mixed gender Japanese quail were assigned to 4 treatment groups, each group being replicated 4 times and containing 15 birds in each replication. Birds were provided with either a basal diet (control) or basal diet supplemented with 0.5%, 1% and 2% GP for 5 wk. At slaughter age, birds fed 1% GP had higher (P < 0.05) live weight and body weight gain when compared to the control. Supplementation with different levels of GP had no influence (P > 0.05) on feed intake, feed conversion ratio except 3rd wk, carcass traits and abdominal fat. Thiobarbituric acid, peroxide and pH values in breast meat of birds receiving GP (1% or 2%) after storage (0, 1, 3, 5, and 7 d) were lower (P < 0.05) than the birds in control. Furthermore, total psychrophilic bacteria count was lower in breast meat of birds supplemented with GP at any dose compared to the birds of control. Sensory characteristics such as color, aroma, juiciness and tenderness were observed significantly better (P < 0.05) in GP supplemented groups especially when fed 1% GP. In conclusion, supplementing the diet with 1% to 2% GP demonstrated growth-promoting effects and positively impacted meat quality, including sensory characteristics.

Effects of packaging methods and temperature variations on the quality and microbial diversity of grouper (Epinephelus Lanceolatus) during cold storage

Microbial growth and its metabolism are the primary reasons for fish spoilage. In this study, the effects of temperature fluctuations and modified atmosphere packaging (MAP) on the quality and microbial diversity of grouper (Epinephelus lanceolatus) during cold storage were investigated. Fish fillets were packed in air packaging (AP), vacuum packaging (VP), MAP1 (40% CO2/55% N2/5% O2), and MAP2 (60% CO2/35% N2/5% O2), and stored at T1 (4 °C) and T2 (4–8 °C temperature fluctuations), respectively. Total viable counts (TVC), psychrophilic bacteria count, Pseudomonas count, and H2S-producing bacteria count all increased during cold storage. Pseudomonas, Serratia, and Carnobacterium were the dominant genera in AP, VP, and MAP2 at T1 storage, with relative abundances of 82.7%, 54.5%, and 57.3%, respectively. Temperature fluctuations accelerated the spoilage process of the grouper, and increased the relative abundance of Serratia in the samples, but had less effect on the composition of these spoilage bacterial members. The microbial community was more affected by the different gas atmospheres. MAP inhibited the growth of Pseudomonas and increased the relative abundance of Carnobacterium and Psychrobacter in the samples. Low temperature and MAP effectively suppressed the rise of pH, total volatile basic nitrogen (TVB-N), trimethylamine (TMA), thiobarbituric acid reactive substances (TBARs), and K values and maintained the water holding capacity (WHC) and sensory quality of the samples. Grouper had the longest shelf life under MAP2-T1 treatment. The MAP2-T1 samples maintained lower levels of TVB-N (151.8 mg/kg), TMA (7.6 mg/kg), TBARs (0.90 mg MDA/kg), and K value (48.5%) and higher levels of WHC (77.6%) on the 18th day, with a lower degree of spoilage compared to other samples.

Düşük Basınç Uygulaması Taze ve Depolanmış Sudak Balığının (Sander lucioperca) Fizikokimyasal ve Mikrobiyolojik Özelliklerini Geliştirdi

IIn this study, low-pressure treatment was applied to pike-perch and the changes in quality criteria during the storage process were examined. L*, a*, and b* values in samples treated with low pressure were significantly different compared to the control. It was observed that the process had an improving effect on the textural properties of the fish. While the aw value decreased to 0.822, the pH value decreased to 6.47. While TBARS values of the samples ranged between 0.014 and 0.031 mg MA / kg, TVB-N values ranged between 7.69 and 24.06 mg / 100 g. Total aerobic mesophilic bacteria, yeast/mold, total coliform group bacteria, and total aerobic psychrophilic bacteria counts of all samples exposed to low-pressure treatment were lower than the control during storage. As a result, the treatment positively affected the quality of pikeperch meat during the storage period.

Çaça (Sprattus sprattus, L., 1758) Protein Hidrolizatının Fizikokimyasal Özellikleri ve Alabalık (Oncorhynchus mykiss, Walbaum, 1792) Filetolarında Kaplama Malzemesi Olarak Kullanımı

Trout is the most widely cultivated and traded fish species in Turkey and many European countries, and a total of 471686 tons of production was realized in Turkey’s seas and inland waters in 2021. In addition to its nutritive value, this fish takes a crucial position in the aquaculture sector due to its continuous and intensive production. In this study, innovative bioactive protein hydrolysates (PH) produced from sprat were used as a coating to increase the quality and shelf life of trout fillets stored at +4 ˚C. The yields of traditional hydrolysate (TH) and ultrasound-assisted hydrolysate (UH) were 8.66% and 12.63%, respectively. Protein values of TH and UH were 75.88 and 74.45%, respectively. Three fillet groups were prepared from trout: uncoated control group (C), traditional enzymatic protein hydrolysate coated group (THC), and ultrasound-assisted enzymatic protein hydrolysate coated group (UHC). TVB-N value, which was 12.96 mg/100g in fresh trout, exceeded the consumable limit with 38.52 mg/100g on the 9th day of storage in the C. This value reached 32.92 mg/100g and 33.62 mg/100g on the 12th day for THC and UHC, respectively. At the beginning of storage, 0.21 mg MA/kg TBA reached the consumable limit with 7.72 mg MA/kg in the C on the 9th day, while THC and UHC remained within the limit with 6.67 mg MA/kg and 6.79 mg MA/kg, respectively. Total aerobic mesophilic bacteria (TAMB) and total aerobic psychrophilic bacteria (TAPB) counts on day 0 of storage were 2.13 log cfu/g and 1.66 log cfu/g, respectively. These values were calculated as 6.90, 5.20, 5.04, 6.95, 3.48, and 3.22 log cfu/g for C, THC, and UHC on the 12th day of storage, respectively. The application of ultrasound during the production of protein hydrolysate significantly increased the yield and hydrolysis degree of UH compared to TH. The lipid ratio of UH was also found to be significantly lower than TH. In these respects, the application of ultrasound has provided an advantage. Although both coatings have provided significant protection compared to the C, generally similar results were obtained between the THC and UHC. PH coatings delayed the chemical, physical, and microbial spoilage of trout fillets and extended the storage period. The results showed that PH can be used as a coating on fish fillets stored in cold conditions.

تقييم تأثير النيسين وسوربات البوتاسيوم ولاكتات الصوديوم في أكسدة الدهون وبعض الخصائص النوعية والمايكروبية للحم البقر المفروم المبرد

This study was conducted to analyze the effects of nisin, potassium sorbate and sodium lactate and their interactions in fat oxidation and some quality and microbial characteristics of chilled ground beef meat stored at 4˚C for 0, 4, 8 and 12 d. All nisin, potassium sorbate and sodium lactate treatments significantly increased pH. Total volatile nitrogen (TVN), peroxide value (PV) and free fatty acids (FFA) were decreased (P&lt;0.05) in nisin, potassium sorbate and sodium lactate treatments when compared with the control sample at all refrigerated storage time. Nisin, potassium sorbate and sodium lactate treatments reduced (P&lt;0.01) the psychrophilic bacteria count during refrigerated storage times.

The effects of ozonated slurry ice treatment on microbial, physicochemical, and quality of large yellow croaker (Pseudosciaena crocea) during cold-chain circulation

Cold chains are effective in maintaining the quality of aquatic products and reducing food losses, especially for dynamic transportation. The purpose of the research was to evaluate the effects of different ice treatments on the microbial, physicochemical, and quality characteristics of large yellow croaker (Pseudosciaena crocea) during cold-chain circulation. Different ice treatments (flake ice (FI), slurry ice (SI), and ozonated slurry ice (OSI)) were used during circulation, respectively. Changes in microbial (total viable count (TVC), psychrophilic bacteria count (PBC), H2S-producing bacteria count, pseudomonas bacteria count), physicochemical (pH, K-value, total volatile basic nitrogen (TVB-N), thiobarbituric acid (TBA), biogenic amines (BAs) content, color difference, texture profile analysis (TPA)) was measured. Low-field nuclear magnetic resonance (LF-NMR) and magnetic resonance imaging (MRI) were also measured to evaluate the feasibility of preservation methods. The results demonstrated that compared with SI treatment, the growth of psychrophilic bacteria, H2S-producing bacteria, and pseudomonas bacteria was inhibited by OSI treatment on the 21st day (0.55, 0.24, and 0.73 log CFU/g reduction, respectively). Besides, OSI treatment exhibited inhibitory activity toward K-value and BAs during storage, along with texture softening. Compared with FI treatment, OSI could retard the water migration and extend the shelf-life of large yellow croaker (Pseudosciaena crocea) for another 6 days. Therefore, ozonated slurry ice will be a promising long-term preservation method for maintaining the quality of large yellow croaker.

Microbiological status of smoked fish placed on the market in Poland

Fish and fishery products are considered to be one of the most nutrient-rich dietary products. The nutritional value of fish depends on its freshness. The greatest role in fish spoilage is played by microbial decomposition. Smoking is one of the methods of fish preservation based on the action of temperature and the penetration into the tissue of preservative substances produced by burning wood. Almost all microorganisms except some pathogenic bacteria are destroyed in the smoking process; nevertheless, fish can be a source of some pathogenic microorganisms, i.e. Listeria monocytogenes, Salmonella spp., Staphylococcus spp., which are present as the result of cross-contamination at the stage after smoking, i.e. marketing and storage (4, 5, 8). Improper and unhygienic handling practices with the ready-to-eat RTE product are also the cause of an increase of the total microbiological contamination, which can be expressed by microbiological contamination indicators, i.e. total viable count (TVC), psychrophilic bacteria count (PBC), coliform count (EBC), total yeast and mould count (TYMC) and total staphylococci count (TSC). In the performed study five smoked fish species (redfish, mackerel, codfish, sprat and herring) were tested at the marketing stage. A total number of 50 (N = 50) samples was tested according to ISO standards. The potential foodborne bacteria in the tested samples were identified using a MALDI-TOF spectrometer combined with MALDI-Biotyper 3.0 software. In the performed study, the highest microbiology contamination TVC on the level 3.63 ± 0.15 log10 cfu/g and PBC on the level 3.04 ± 0.24 log10 cfu/g has been found in redfish muscle compared to herring, codfish, sprat and mackerel muscle. A significantly lower amount of 1.26 ± 0.12 log10 cfu/g yeast and moulds of was found in the muscle tissue of herring, compared to the other tested fish. The highest staphylococcal contamination of muscle tissue of redfish on the level 2.56 ± 0.15 log10 cfu/g and mackerel on the level 2.13 ± 0.15 log10 cfu/g was found. MALDI-TOF identification of isolated bacteria not confirmed the presence of Salmonella spp., Listeria monocytogenes and pathogenic Staphylococci and confirmed the presence of E. coli in tested redfish.

Effect of some organic acids on spoilage and pathogenic bacteria in broiler carcasses

A Total of six groups of fresh broiler carcasses randomly collected from different poultry shops at Alexandria province. After examination of an untreated samples, the samples were classified into six groups, each group was represented by their muscle samples which were dipped in acid solutions as follows; the 1st group was dipped in 1% lactic acid solution v/v for five min., the 2nd group was dipped in 2% lactic acid solution v/v for five min., the 3rd group was dipped in 1% acetic acid solution v/v for five min., the 4th group was dipped in 2% acetic acid solution v/v for five min., the 5th group was dipped in 1% mixture of lactic and acetic acids v/v for five min. and the 6th group was dipped in 2% mixture of lactic and acetic acids v/v for five min. Determination of spoilage markers including determination of pH and total volatile nitrogen (TVN) was performed beside determination of aerobic plate count (APC), psychrophilic bacteria count and Enterobacteriaceae count. The inhibitory effect of lactic acid and acetic acid on microbial population has long been used to preserve food from spoilage, while much of the effect can be accounted for pH and temperature of storage. Immersion of the examined samples with 1, 2 % (lactic, acetic acids). chilled for 1, 2, 4, 6, 8, 10 and 12 days resulted in population reductions of aerobic bacteria, psychrophilic and Enterobacteriaceae. Effect of organic acids as lactic acid, acetic acid and mixture of lactic and acetic acids are mainly affecting growth of microorganisms mainly by lowering of pH and increase acidity of media. The acids have effect until 10 days of storage at chilling condition in case of 1% concentration, but its effect reach to 12 days in case of 2% concentration.

Evaluation of the qualitative properties and consumer perception of marinated sardine Sardina pilchardus: The effect of fucoxanthin addition

With the increasing consumer awareness and demand for healthy food and natural ingredients; there is an urgent need to develop and propose innovative products to industry. In this study, the combined effect of various time of pre-incubation (30, 60 and 90 min) in vinegar and the addition of fucoxanthin (Fux) extracted from the brown alga Dictyopteris polypodiodes to the covering oil of sardine fillets was investigated during 3 months of refrigerated storage at 4°C. Compared to fresh sardines, biogenic amines (Bas) decreased significantly in all marinated lots (histamine <0.07 mg/100 g, cadaverine <0.0 mg/100 g) and remained far below the regulatory limit up to the end of storage indicating the inhibition of specific bacteria producing amines. This was confirmed by the psychrophilic bacteria count which remained low (<1 log CFU/g) in all marinated lots. The antioxidant effect of fucoxanthin was reflected by the significantly higher contents of polyunsaturated fatty acids and the lower levels of thiobarbituric acid (5.50 ± 0.24 mg MDA/kg) in the fucoxanthin-marinated sardine especially toward the end of storage. Among the six tested lots, and based on acceptance test, consumer identified the 60min-fucoxanthin-lot as the preferred product. Principal compound analysis allowed the distinction between lots treated with/without fucoxanthin during refrigerated storage indicating its clear preservative effect.

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.

Effects of chitosan coating on quality and protein characteristics of large yellow croaker ( Pseudosciaena crocea ) during ice storage

This project aimed to evaluate the effects of chitosan (CS) on the quality and protein characteristics of large yellow croaker (Pseudosciaena crocea) during ice storage. Samples were treated with different solutions (10.0 g/L chitosan solution (CS1), 20.0 g/L chitosan solution (CS2), 1% acetic acid (AA), deionized water (CK)) for 15 min then stored at 4°C. Microbiological (total viable counts (TVCs) and psychrophilic bacteria counts (PBCs)), physicochemical (total volatile basic nitrogen (TVB-N), thiobarbituric acid (TBA) and texture profile analysis (TPA)) were used to analyze the quality of large yellow croaker. The changes of protein characteristic were analyzed by total sulfhydryl (-SH) content, Ca2+-ATPase activity and Fourier transforms infrared spectroscopy. The results showed that chitosan could effectively inhibit the microbial growth, and the hardness value was consistent with the reduction of protein characteristic indicators (-SH content and Ca2+-ATPase activity). For protein structure analysis, the amide I band and amide II band of CK group changed significantly, which indicated that α-helix might be transformed into β-fold or random coil. Therefore, 20.0 g/L chitosan treatment had better effect, it could extend the shelf-life for another 6 days, which had also protective effects on the secondary structure of protein and maintained its structure stability.

Effects of slightly acidic electrolyzed water pretreatment combined with compound bio‐preservatives on quality and microbiota changes of refrigerated obscure pufferfish ( Takifugu obscurus )

The evaluation of ε-polylysine hydrochloride (PLH) and rosemary extract (RE) combined with slightly acidic electrolyzed water (SAEW) on the quality and microbiota changes of obscure pufferfish (Takifugu obscurus) was studied during refrigerated storage at 4 ± 1°C. The fish samples were first impregnated with SAEW and then dissolved in sterile water (CK) and different solutions (0.2% RE, 0.3% PLH, 0.2% RE+0.3% PLH (RP)). Changes in microbiological indicators (total viable counts [TVC], psychrophilic bacteria counts [PBC], pseudomonas bacteria counts, H2S-producing bacteria counts) and physiochemical indexes (ATP-related compounds, K value, total volatile basic nitrogen [TVB-N], and biogenic amines content) were also examined, the microbial composition of the samples was analyzed using high-throughput sequencing. Results showed that PLH treatment had the lower microbial counts and TVB-N. The degradation of inosine monophosphate (IMP), the production of hypoxanthine riboside (HxR) and hypoxanthine (Hx) in treated groups were slower than that of CK group. Moreover, RP group effectively delayed the production of biogenic amines. Illumina-MiSeq high throughput sequencing results demonstrated that the microbiota of each group became less diverse during storage, and Janthinobacterium in treated groups increased significantly. Pseudomonas became the major predominant microbiota of obscure pufferfish (Takifugu obscurus) at the end of storage. According to the results of TVC, SAEW combined with RP could prolong the shelf-life of obscure pufferfish for another 6 days. Practical applications Obscure pufferfish (Takifugu obscurus) is enthusiastically welcome due to the palatability and nutritional value of its flesh. However, it is vulnerable to spoilage caused by microbial growth and metabolisms. Based on the results of microbiological analysis total viable counts, compared with CK group, samples with compound bio-preservatives treatment maintained good quality and prolonged the shelf life of obscure pufferfish for another 6 days.

Potential Applications of Antibacteria in Edible Coating as Fish Preservative

Fish is a product that breaks down quickly due to biochemical reactions that cause a decrease in the quality of its nutritional and sensory values. Natural preservatives make fish safer for consumption than fish preserved with formalin. Edible coating is a preservative that can be eaten, can prevent biological, chemical and physical changes, is able to prevent mass transfer, acts as a moisture barrier, be contained antimicrobial/antibacterial and antioxidants, increases shelf life, as well as protects food from microbial contamination. Antimicrobial/antibacterial compounds added to edible coatings are able to inhibit food degradation and/or remodel toxic compounds such as free radicals. Antimicrobials can be obtained from plant extracts such as alkaloids, flavonoids, saponins, tannins, phenolic acids, and eugenol. These compounds can slow the growth of bacteria in fish namely Escherichia coli, Pseudomonas aeruginosa, Staphylococcus sp., Staphylococcus aureus, Psychrotrophic and Psychrophilic bacteria counts, Enterobacteriaceae, and lactic acid bacteria. This article reviews the application of various antibacterial compounds from various plants that are added to edible coatings as preservatives in fish.

Multi-frequency ultrasound:A potential method to improve the effects of surface decontamination and structural characteristics on large yellow croaker (Pseudosciaena crocea) during refrigerated storage

The effects of multi-frequency ultrasound on surface decontamination and structural characteristics of large yellow croaker (Pseudosciaena crocea) during refrigerated storage were evaluated. The results of total viable counts (TVCs) and psychrophilic bacteria counts (PBCs) demonstrated that multi-frequency ultrasound retarded the growth of microorganisms. The bacteriostatic effect was positively correlated with the increase of ultrasound frequencies. However, compared with triple-frequency ultrasound (TUS, 20/28/40 kHz) treatment, dual-frequency ultrasound (DUS, 20/28 kHz) treatment had higher water-holding capacity (WHC) and immobilized water content, better texture characteristics, lower pH and total volatile basic nitrogen (TVB-N). Through the results of myofibrillar fragmentation index (MFI), intrinsic fluorescence intensity (IFI) and atomic force microscope (AFM), multi-frequency ultrasound could effectively stabilize the myofibrillar protein structure of refrigerated large yellow croaker, which could maintain better texture characteristics. The effects of DUS were the most significant. Therefore, multi-frequency ultrasound treatment could inhibit the growth of microorganisms and improve the structural characteristics of large yellow croaker during refrigerated storage.

DETERMINATION OF SOME MICROBIOLOGICAL, CHEMICAL AND HISTOLOGICAL PROPERTIES OF SALAMI AND SAUSAGES SOLD IN MARKETS

Salami and Sausage are ready to eat meat products that can pose a risk for human health. This study was aimed to determine the some microbiological, chemical and histological properties of 31 salami and 23 sausages from different companies offered for sale in markets, Turkey. The total aerobic mesophilic bacteria (TAMB), yeast and mould enumeration, lactic acid bacteria and psychrophilic bacteria count were evaluated. The water activity, pH, moisture content, and ash content were analysed. The mean TAMB value of salami and sausage samples were 2.30 log CFU/g and 2.80 log CFU/g, respectively (P&gt;0.05). The water activity was found as 0.97 for both samples. The pH value of salami and sausage samples were 5.94 and 5.87, respectively (P&gt;0.05). Moisture content was higher in salami samples (63.80%) than sausage samples (62.00%) (P&gt;0.05). The average ash content in salami samples was 2.15%, while it was 2.80% in sausage samples (P&gt;0.05). In conclusion, the microbiological and chemical analysis of sausage and salami products were within the range of Turkish standards. However, histological analysis revealed that some packed sausage and salami products sold in market are manufactured from lower-value trimmed food.

Determination of the Risky Microorganisms in Frozen Ready-to-Eat Seafood Sold in Istanbul Market

Since frozen ready-to-eat seafood has the potential to cause food poisoning, this study focuses on microorganisms that have the potential to be a health hazard found in frozen ready-to-eat seafood, which is sold to highly populous communities. Therefore, the most popular frozen ready-to-eat seafood, fish balls and surimi crab legs, from Istanbul market were studied. Samples were gathered from seven different branches of four major chain market brands, twice in winter (October-March) and twice in summer (April-September). As a result of seasonal conditions summer samples had higher microbial loads compared to winter samples. The average mesophilic and psychrophilic aerobic bacteria counts of fish balls and surimi crab legs were below ≤4 log cfu/g. All samples were safe in terms of Salmonella, Vibrio parahaemolyticus and Vibrio cholerae; and acceptable in terms of Staphylococcus aureus Clostridium perfringens, and Bacillus cereus. The microbiological load of fish balls was higher (p&lt;0.05) than the other samples. It was observed that more than 80% of them are risky in terms of coliform bacteria. It is concluded that attention should be paid especially to minced and spice added products. It is essential to pay more attention to the marketing of ready-to-eat seafood during the summer seasons for the prevention of public health.

Comparison of microwave-assisted induction heating system (MAIH) and individual heating methods on the quality of pre-packaged white shrimp

Microwave-assisted induction heating (MAIH) is a novel heating technology that combines microwave heating in the upper section and induction heating at the bottom. Our previous study demonstrated that optimal cooking in white shrimp can be achieved by MAIH either at 130 °C for 80 s or at 90 °C for 100 s. The objective of this study was to compare the cooking of white shrimp using microwave heating or induction heating alone with that using MAIH under the optimum cooking condition. The following three methods for cooking white shrimp were analyzed: (1) induction heating (IH) at 90 °C for 100 s or at 130 °C for 80 s; (2) microwave heating (MW) at 1300 W and 2450 MHz for 80 or 100 s; and (3) MAIH at 90 °C for 100 s or at 130 °C for 80 s. The results showed that using only induction or microwave heating gave the shrimp an uncooked or undercooked appearance; meanwhile, cold spots and non-uniform temperature distribution were observed in the thermal image of the shrimp. On the contrary, the shrimps processed by MAIH were found to be fully cooked, and a uniform temperature distribution was observed in the corresponding thermal image. Furthermore, no detectable aerobic plate count (APC), psychrophilic bacteria count (PBC), and coliform were found in the shrimp samples processed by MAIH. The color (L*, a*, b*, W, and ΔE), hardness, cohesiveness and chewiness of the samples processed by MAIH were all significantly greater (p < 0.05) than those of shrimp processed by induction or microwave heating alone, indicating that MAIH cooking shrimp exhibited better color and texture than MW or IH alone. The results showed that the shrimps heated with MAIH at both 130 °C or 90 °C had better microbiological, physical and chemical quality, as compared to MW or IH heating alone. Industrial relevanceThis novel MAIH technology allows shrimp to be heated and pasteurized after being packed, thereby eliminating the post-pollution issue. Therefore, it has a great potential for developing short-time in-package pasteurization processes in food industry.

Combining slightly acidic electrolyzed water and slurry ice to prolong the shelf‐life of mackerel ( Pneumatophorus japonicus )

The comprehensive effects of slightly acidic electrolyzed water and slurry ice (SAEW-SI) on the growth of microorganisms, physicochemical reaction, and sensory attributes of mackerel (Pneumatophorus japonicus) were evaluated during storage at 4°C. The changes in microbiological (total viable counts (TVCs), psychrophilic bacteria counts, pseudomonas bacteria counts, H2S-producing bacteria counts), physicochemical (pH, total volatile basic nitrogen (TVB-N), water-holding capacity (WHC), thiobarbituric acid reactive substances (TBARS), texture profile analysis (TPA), color difference, adenosine triphosphate (ATP)-related compounds), protein characteristic (SDS-PAGE, fluorescence spectroscopy analysis), and sensory evaluation were analyzed. It was observed that the SAEW-SI treatment had a strong inhibitory effect on microbial growth (5.8 log CFU/g on 24th day). And SAEW-SI could alleviate the oxidation degree of myoglobin and lipid, thus the color of samples was greatly maintained. According to the sensory attributes, the shelf-life of samples in the SAEW-SI group increased by 6 days compared to the control group. Therefore, SAEW-SI could be a useful preservation approach for the fish industry. Novelty Impact Statement The comprehensive effects of SAEW-SI on the quality of mackerel (Pneumatophorus japonicus) were evaluated during storage at 4°C. SAEW-SI showed the best antibacterial potential without any deleterious effects on the mackerel. SAEW-SI could extend the shelf-life of mackerel for another 6 days with a high sensory score.