Anaerobic Plate Counts Research Articles

Shrimp Digestive Bacteria Performance for Shrimp Waste Chitin Extraction

Generally, chitin is isolated chemically. An environmentally friendly alternative to chitin extraction is enzymatic extraction. The research aims to determine the effectiveness and optimum conditions for enzymatic chitin extraction of shrimp waste (heads, shells, and tails) using lactic acid bacteria (LAB) and proteolytic bacteria from the shrimp's digestive tract (faeces and intestines). The research stages were isolation, enrichment, and determining shrimp digestion's bacterial colonies, microscopic identification of shrimp digestive bacteria, and determining the effectiveness and optimal conditions for shrimp waste's chitin isolation. Aerobic and Anaerobic Total Plate Count (TPC), LAB, and proteolytic bacteria from shrimp's digestive tract per gram of sample were respectively 5.52 and 5.59 log CFU; 4.76 and 4.56 log CFU; 6.46 and 6.20 log CFU. Microscopic morphology shows that LAB and proteolytic bacteria of shrimp digestive are gram-positive as cocci or rods. The deproteinization value of shrimp waste reached 31%, especially for treatment with a pH of 5.0–7.0 (during proteolytic bacteria fermentation) and pre-treatment of boiling, drying and coarse grinding of shrimp waste (PP2) before extraction. However, the demineralization value of shrimp waste is only 4.5% (PP1) and 3% (PP2), with LAB as the primary fermentation agent because proteolytic bacteria have been unable to reduce the mineral content in shrimp waste further.

Nisin and Organic Acid Salts Improved the Microbial Quality, Extended the Shelf Life, and Maintained the Sensory Attributes of Semidry Beef Luncheon Marketed at Adverse (35-40 °C) Ambient Summer Temperatures.

Semidry beef luncheon may undergo deteriorative changes during storage at ambient temperatures in tropical and subtropical regions including Egypt. This study was conducted in a meat plant in Egypt with the aim of overcoming the economic losses from the returns of spoiled unsold beef luncheon displayed in grocery stores at adverse summer temperatures of 37 °C or more. Ten approaches were applied using different preservatives, comprising sodium nitrite, nisin, potassium sorbate, and organic acid salts (a combination of sodium lactate, sodium acetate, and sodium diacetate). In addition, the product was cooked at different temperatures and was stored for 21 days at 37 °C, during which time the shelf life, microbial quality, pH, and sensory attributes were investigated. By Day 21 of storage, the luncheon contained 50 mg/kg sodium nitrite, 25 mg/kg nisin, and 1000 mg/kg organic acid salts and, when cooked at a final core temperature of 92 °C, exhibited reductions in aerobic plate count, anaerobic plate count, lactic acid bacterial count, and mold and yeast counts by 4.32, 3.54, 3.47, and 1.89 log10 CFU/g, respectively, when compared with the control. The sensory attributes and pH were also maintained in the final products of such treatment, with no product return and the avoidance of economic loss. This study presents a novel approach for solving the major problem of the deteriorative changes that occur in semidry luncheon sausage and similar meat products which require rejection with a huge economic loss, especially in tropical and semitropical areas of the world that have similar problems of high climatic temperatures and a low availability of energy or technological resources.

Microbiological Parameters of Different Waste Waters to Evaluate Their Potential to be Use as a Media for Chlorella sp. and Spirogyra sp. Cultivation

Globally there is severe water scarcity, and methods to reuse wastewater need to be adapted. The objective of this research was to determine the microbiological parameters of different wastewaters in order to study the potential of wastewater as a media to cultivate algae.Food, agriculture, drainage and municipal wastewater sample were collected in sterile bottles separately. Aerobic, anaerobic plate counts, yeast and mold counts were evaluated. Enumeration of coliform, fecal coliform, coliphages and microalgae was performed with all wastewater samples. Chlorella sp. and Spirogyra sp. were isolated from three different paddy field water samples, and growth studies were carried out in different wastewater media with standard sterile Chu’s medium and in sterile tap water medium as control.Heterotrophic, anaerobic bacteria, microalgae, yeast and molds were found in all types of wastewater. Agriculture wastewater had the highest value for aerobic, anaerobic, yeast and mold count in the highest dilution. Coliforms and fecal coliforms were absent in food and agriculture wastewaters on Eosin Methylene Blue (EMB) medium. Coliform and Fecal coliforms were only observed in drainage and municipal wastewater on Endo agar (EA) medium. Coliphages were absent only in agricultural wastewater and found in the highest numbers in municipal wastewater. Except for agricultural wastewater, other three types of wastewaters contain microbial contaminations. Agriculture wastewater medium significantly enhanced the growth of Chlorella sp. than the standard Chu’s medium. The growth of Spirogyra sp. was stimulated by the food wastewater medium than the other media.
 Keywords: Wastewaters, Microbiological parameter, Chlorella sp., Spirogyra sp., Coliforms

Effects of Modified Atmosphere Packaging with Different Gas Ratios on the Quality Changes of Golden Pompano (Trachinotus ovatus) Fillets during Superchilling Storage.

The quality changes of golden pompano fillets in air packaging (AP) and modified atmosphere packaging (MAP) with 30% CO2/70% N2, 50% CO2/50% N2, and 70% CO2/30% N2 were evaluated under superchilling (−3 °C). The results showed that the whiteness of fillets decreased during storage. The rate of pH increase of MAP was significantly slower than in AP groups, in which MAP with 70% CO2/30% N2 effectively suppressed the PH. Interestingly, the hardness decreased on day five following the treatments, followed by a relatively stationary trend. MAP could greatly suppress the increase of total volatile basic nitrogen (TVB-N) contents of fillets compared to fillets packed in AP. All MAP groups of fillets maintained first-grade freshness throughout storage, while the AP samples decreased to second-grade freshness on about the 25th day. MAP with 70% CO2/30% N2 and MAP with 50% CO2/50% N2 had the best results in inhibiting protein degeneration and explanation. Unexpectedly, drip loss of fillets in MAP far exceeded the AP group during storage, which causes sensory discomfort. Anaerobic plate count (APC) of fillets in AP exceeded the consumption limit of 6.7 log CFU/g on day 26 (6.75 log CFU/g on the 26th day), whereas the MAP was still microbiologically acceptable after 30 days of storage (6.43, 6.41, 6.22 log CFU/g, respectively). Considering physicochemical and microbiological parameters, the shelf life of fillets packed in AP was 25 days. MAP treatments could prolong the shelf life of fillets by ~4–5 days compared to AP. Overall, MAP with 70% CO2/30% N2 gas ratio was best for inhibiting the quality deterioration of fillets. Furthermore, principal component analysis (PCA) was performed to evaluate the critical indicators of quality deterioration of the fillets. Two principal components were determined by dimensionality reduction, in which the contribution of the first principal component was centrifugal loss > hardness > TVB-N > APC > CO2 solubility > TBARs > drip loss > pH, which mainly reflected the degree of microbial proliferation, protein hydrolysis, and oxidation. The contribution of the second principal component was pH > TBRAs > drip loss > APC > CO2 solubility > TVB-N > hardness > centrifugal loss, indicating a high correlation between lipid oxidation and microbial proliferation index.

The Microbial Quality of Commercial Chopped Romaine Lettuce Before and After the "Use By" Date.

In the United States, due to the limited information about the microbial quality and safety of fresh produce after the labeled open dates, unnecessary discarding of fresh produce in good conditions and food loss have been caused. The aim of this study was to address this knowledge gap and evaluate the microbial quality of commercial chopped Romaine lettuce (RL) on the “Use By” dates (UBD) and 5 days after the “Use By” dates (UBD5). The microbial quality was evaluated using culture-dependent and culture-independent methods. Three brands of RL samples, from early and late harvest seasons, were purchased from local grocery stores and stored at 4°C until 5 days after their UBD. On the UBD and UBD5, bagged lettuce was opened, homogenized, diluted, and plated onto plate count agar and anaerobic agar to obtain total aerobic plate counts (APC) and total anaerobic plate counts (AnPC). For the culture-independent method, DNA was extracted from each sample homogenate and used for 16S rRNA gene sequencing. The culture-dependent results showed that there was no significant change in APC or AnPC between UBD and UBD5 samples. The APC and AnPC ranged from 5.71 ± 0.74 to 7.89 ± 0.10 Log CFU/g and 1.75 ± 0.08 to 7.32 ± 0.61 Log CFU/g, respectively. No significant difference in alpha diversity, based on observed features and Shannon index values, was detected between UBD and UBD5 samples using 16S rRNA sequencing. Similarly, no difference was observed in beta diversity based on the Jaccard distance matrixes and the weighted Unifrac distance matrixes. Taxonomic analysis revealed 128 genera in all RL samples. The top five genera were Pseudomonas (with relative abundance ranging from 16.47 to 92.72%), Serratia (0–52.35%), Weissella (0–42.42%), Pantoea (0.17–21.33%), and Lactococcus (0–24.30%). The differential abundance analysis based on the ANCOM test showed that no bacteria were detected to have significantly differential abundance in RL between UBD and UBD5. In summary, both the culture-dependent and culture-independent results showed that there was no significant difference in the microbial quality of RL before and shortly after the UBD.

Retort processing of traditional chicken biriyani and its microbiological quality

Traditional dishes such as chicken biriyani are relished by many and consumed in almost every celebration. The lifestyle changes and rapid urbanisation calls for the development of readyto- eat processed foods, which are safely processed and neatly packed. Retort processed shelfstable foods are an alternative to such a demand. In the study conducted, the retort processing conditions of traditional chicken biriyani was standardised and commercial sterility of the product was analysed. Microbiological parameters such as aerobic and anaerobic plate counts were assessed on 0th, 30th, 60th, 90th and 120th days of storage. The commercial sterility test was satisfactory and the microbiological analysis revealed an absence of bacterial colonies throughout the storage study. The highly perishable, traditional product was sterile on all days of storage study and was suitable as a shelf-stable product for mass production.

A pig slurry feast/famine feeding regime strategy to improve mesophilic anaerobic digestion efficiency and digestate hygienisation.

The increasing concentration of livestock farms results in large amounts of waste production and the need for their management. The study of anaerobic digestion (AD) technology, under mesophilic conditions, applied to pig slurry is of the upmost importance for biogas recovery and sanitised digestate, contributing to a circular economy. The assessment of the effects of a feast/famine regime on biogas and biomethane (bio-CH4) yield with different feeding frequencies was performed. The evaluation was made in regards to three scenarios: the first is based on daily feeding (FR1); in the second, the feeding occurs once every two days (FR2); and in the third, the feeding happens once every three days (FR3). The results demonstrate that the biogas and methane yield increased by 34% and 37% between FR1 and FR3. The stability inside the reactor was maintained since specific loading energetic rate values did not exceed the recommended limit (0.4 d-1). It was also possible to conclude that the AD technology was efficient to sanitise the pig slurry, with the count of Escherichia coli going from 1 × 105 colony-forming units (CFU) g-1 to less than 100 CFU g-1, meeting the legal requirements for agricultural valorisation. The total anaerobic mesophile plate counts were significantly (p < 0.1) reduced from feeding to digestate, and the plate counts of Clostridia were significantly (p < 0.05) increased, reflecting the changes in the composition of the microbiota. The increasing yield in bio-CH4 in accordance with Clostridium counts suggests this genus as a positive microbiological key indicator of the AD performance.

Bacteriological Quality of Canned Meat Marketed in Egypt

Abstract Because of rapid and busy life style, canned meat are widely consumed in Egypt. Therefore, the main objective of the current study was to evaluate the bacteriological status of canned meat marketed in Beni-Suef city. A total of 150 samples of canned meat represented by canned beef, corned beef, canned chicken sausage, canned chicken luncheon, canned luncheon and canned sausage (25 each) were examined for anaerobic plate count, Staphylococcus aureus count , enterococci count, total Clostridial count and isolation of clostridium perfringens. The highest prevalence of Clostridia were recorded in corned beef and canned sausage (60% each), while their lowest ones were in canned beef and canned poultry sausage (28% each). Twenty, 24%, 16, 12%, 24 and 24% of canned beef, corned beef, canned chicken sausage, canned chicken luncheon, canned luncheon and canned sausage, respectively exceeded the permissible limits of the E.O.S (2005) in relation to staph. aureus count. Enterococci could not be detected from canned chicken luncheon and canned sausage, while the levels of detection in canned beef, corned beef, canned chicken sausage, and canned luncheon were 12, 28, 4, and 12%, respectively. Cl. perfringens failed to be isolated from all the examined samples. It could be concluded that some of the examined samples were exceeding the local and international permissible limits for the examined bacteria, which may reflects under processing or poor storage conditions.

Nutritional Content and Microbial Quality of Complementary Foods Produced from Blends of Orange-Fleshed Sweet Potato and Edible Insects

Abstract Objectives Improved formulations of complementary foods (CFs) with animal-source foods (ASFs) is an eminent strategy to improve infant nutrition, but they are expensive and not readily available in many food insecure settings which are a haven of edible insects. Hence, we developed orange-fleshed sweet potato (OFSP) based CFs supplemented with Cricket or palm weevil larvae (PWL), examined its nutritional content and microbial quality for infant feeding. Methods OFSP roots were sourced from local farmers, peeled, sliced, steam cooked and mechanically dried into OFSP flour. Cricket powder and PWL paste were obtained from commercial producers, steam cooked, and mechanically dried into Cricket/PWL flours. OFSP flour was mixed with either Cricket/PWL flours in the ratios of 100:0 (control), 85:15, 70:30, and 50:50 and used to produce ready-to-eat CFs. The CFs were evaluated for nutrient composition and microbial contamination using standard methods. ANOVA followed by Dunnett's test was used to compare all the formulations to the control. Results There were increase in protein (4.80 to 36.75%), iron (1.26 to 4.38 mg/100 g), zinc (0.69 to 10.65 mg/100 g) and calcium (45.54 to 152.77 mg/100 g) contents of the OFSP-based CFs with increased supplementation with Cricket/PWL flour. The carbohydrate and β-carotene content decreased but the energy content increased with increased supplementation with cricket/PWL flour from 344.52 Kcal/100 g in 100% OFSP CF to 541.09 Kcal/100 g in 50:50 CFs (OFSP: PWL) (P = 0.001). Aerobic mesophilic count (AMC) of the OFSP: Cricket CFs was 60 cfu/g as compared to 1300 cfu/g for the OFSP: PWL CFs. Comparing the OFSP-based Cricket/PWL CFs to the commercial Cricket or PWL, there was 35–331-fold reduction in AMC. Bacillus cereus (BC), aerobic (APC) and anaerobic plate count (NPC) was 0 cfu/g for the OFSP: Cricket CFs. BC, APC and NPC were 100, 260 and 130 cfu/g respectively for the OFSP: PWL CFs. Conclusions Steam cooking, then mechanical drying significantly reduced microbial concentrations in commercial Cricket and PWL to below minimum limits set by the Ghana Standards Authority for CFs requiring heating to boiling before consumption. OFSP-based Cricket/PWL composite flours could be safe viable alternatives as nutritious CFs in countries where they are culturally accepted as food. Funding Sources Nutritional Sciences Council at Iowa State University.

High pressure-assisted thermal sterilization of low-acid fruit and vegetable purees: Microbial safety, nutrient, quality, and packaging evaluation

The objective of this study was to assess the influence of pressure-assisted thermal sterilization (PATS) on nutrients and quality of pumpkin, butternut squash, pea, beetroot, and purple potato purees. PATS processing parameters included preheating of purees at 98 °C for 5 min and pressurizing at 600 MPa in a vessel set at 90 °C for 5 min. Colorimetric temperature sensors, two types of Bacillus amyloliquefaciens spores, total aerobic and anaerobic plate count, HPLC, as well as spectrometer and spectrophotometer were utilized. The colorimetric temperature sensor based on its color value when extrapolated suggested the purees' temperature reached 122 °C. Thus, at least 9-log10 reduction of B. amyloliquefaciens spores was achieved in a purple potato puree, and no detectable aerobic and anaerobic microorganisms were found after PATS in all purees. Vitamin C showed 3–14% reduction after PATS. Total chlorophyll and β-carotene did not vary significantly (p > 0.05) after PATS, while betalains and anthocyanin were sensitive and decreased significantly. Interestingly, total color change (ΔE) of pumpkin, butternut squash, and beetroot purees ranged between 2.5 and 3.4 below the threshold (ΔE = 6) value that can be observed by the naked eyes. EVOH-based packages did not show any visual deformation, but their oxygen and water vapor transmission rates increased significantly (p < 0.05) after PATS. The present research suggests that PATS can be used to produce safe and high-quality shelf-stable fruit and vegetable products.

Preservative Effect of Novel Combined Treatment with Electrolyzed Active Water and Lysozyme Enzyme to Increase the Storage Life of Vacuum-Packaged Carp

In the present study, common carp (Cyprinus carpio), a highly valuable worldwide commercial fish species, was used as a model. One sample group of fresh, skin-on carp fillets was placed in a bath of acidic electrolyzed oxidizing (AEO) water containing a solution of 100 mg/kg chloride ion concentration for 5 minutes. Another sample group was treated with acidic electrolyzed water and 0.5% lysozyme enzyme solution. Another set of samples were washed after the AEO water treatment. Within the study, a storage test was performed to examine the effect of the new combined treatment on the samples’ shelf-life and quality while kept at 2°C. During the storage period, chemical (chlorate) and microbiological (TVC, mesophilic anaerobic plate count, and Enterobacteriaceae count) tests and sensory evaluation were conducted. The combination of AEO water and lysozyme enzyme showed additional bactericidal efficacy on the surface of the carp fillets, which has never been reported before. Both the AEO water and the combined treatment effectively increased the shelf life of the samples, causing 2.4–3.1 log CFU/g difference compared to the control by the end of the 7-day storage. The measured residual chlorate content exceeded the legal threshold, but washing the samples resulted in values below the theoretical threshold limit. The applied preservation methods did not have an adverse effect on the organoleptic properties of the samples.

Impact of par-baking and packaging on the microbial quality of par-baked wheat and sourdough bread

The impact of processing conditions on the microbial quality of par-baked wheat and sourdough bread was investigated. Processing conditions included par-baking time (8 and 13 min), temperature (150 and 200 °C), amount of steam (200 and 600 mL), and packaging (air and modified atmosphere (MA)). Total anaerobic mesophilic plate counts, moulds and yeasts and spore-forming bacteria, together with pH and aw of the par-baked breads were evaluated. Data were used to make predictive models showing the impact of the main effects and their interactions. Sourdough addition could extend the time of acceptable bread quality based on the anaerobic counts from 8 to more than 13 days. Visual growth of moulds and yeasts (presence/absence of single spots) was most efficiently suppressed by the combination of MA-packaging and the highest baking temperature and time. Microbiological analysis of moulds and yeasts however, showed that again sourdough had the best preservation potential, followed by MA-packaging. This study showed that adjusting the par-baking conditions, bread composition and packaging can increase the shelf-life of par-baked bread in a natural way.

Microbiota of lutefisk, a Nordic traditional cod dish with a high pH

Most foods have either a neutral or a slightly acidic pH, whereas only a limited number of products have a pH above 8. The Nordic traditional fish dish lutefisk is an exception, with a pH around 12 during production and a ready for consumption pH above 10. Lutefisk is prepared from dried Atlantic cod (Gadus morhua), soaked in water and thereafter treated in a lye solution. During this process, the muscle proteins are partially hydrolyzed and a characteristic smell and a gel like appearance are developed. Due to its high pH, lutefisk has previously been considered not to harbour any microbiota. However, in our study of commercially available lutefisk, aerobic and anaerobic plate counts of up to 1.4 × 106 and 5.5× 104 CFU g−1, respectively were found. The pure culture isolates from Plate count agar, Iron agar Lyngby and Alkaline Nutrient agar, were identified by 16S rRNA gene sequencing as Carnobacterium maltaromaticum, Pseudomonas fragi, Staphylococcus warneri, S. hominis, Aeromonas salmonicida, Kurthia zopfii, Microbacterium oxydans, Exiguobacterium oxidotolerans, Alishewanella tabrizica and Bacillus licheniformis. This is the first report on the microbiota of lutefisk based on cultivation and 16S rRNA gene sequencing.

Microbiological Assessment of Canned Meat Products with Molecular Detection of Clostridium Perfringens Toxins

The current work was planned to evaluate some locally manufactured canned meat products retailed for sale in Alexandria Province microbiologically beside molecular detection of toxins produced by Clostridium perfringens isolated from the examined samples. To achieve this goal, a total of 100 canned meat samples were randomly collected from different shops and supermarkets. The collected samples were examined bacteriologically at the laboratory of Food Hygiene Department, Faculty of Veterinary Medicine, Alexandria University for determination of aerobic plate count and anaerobic plate count as well as isolation and identification of Cl. perfringens. The obtained results clarified that aerobic plat count was ranged from 3×103 to 15×104 with a mean value of 2.8×106 ± 0.29×104 while the anaerobic plate count was ranged from 3×10 to 11×102 with a mean value of 2.57 ×102 ± 0.16 ×102. Also, it was noticed that 27 and 20% of the examined samples failed to comply with Egyptian Standard Specification of canned meat No. 3491 (2005), for aerobic and anaerobic plate counts, respectively. In addition, the presence of Cl. perfringens was confirmed by neutralization and dermonecrotic tests. Finally, PCR assay was employed for determination of the type of toxins produced by Cl. perfringens.

Evaluation of the Spoilage Microbiota Associated with Sliced Pre-Packaged Deli-Style Ham

ObjectivesThe objective of this study was to evaluate the spoilage microbiota of various sliced, case ready deli-style hams and identify differences between their microbiological communities.Materials and MethodsHam samples were procured at local retail stores from products available on the shelf. Three brands (A, B, C) of smoked, sliced, Ham, Water Added were purchased with a brand being considered the same product and establishment number. Replication was defined as having the same sell-by date indicating a common date of production; 3 different sell-by dates for each brand created 3 replications. Multiple packages of each brand and sell-by date were purchased to allow an unopened package to be used for each sampling date and were stored at 4°C. Sampling times were determined as follows: –4, –2 (4 and 2 wk prior to sell-by, respectively), 0 (sell-by date), 2, and 4 (2 and 4 wk after the sell-by day, respectively). Water activity and salt concentration were sampled at –4 only. Objective color (CIE L*, a*, b*), pH, aerobic plate count (APC) and anaerobic plate count (AnPC) were evaluated throughout storage time. Bacterial community analysis was performed using high throughput 16S rRNA gene sequencing on the Illumina MiSeq platform. Sequences were processed using QIIME, binned into operational taxonomic units (OTUs) at 97% similarity and assigned taxonomy using the Greengenes database as reference. Water activity and salt concentration data were analyzed using R. Color, pH, and plate counts were analyzed as a 3 (brand) by 5 (storage time) factorial using R. Alpha and β diversity of bacterial communities were analyzed using QIIME and R. Alpha diversity was estimated using observed OTUs and Chao1 estimates, and β diversity was determined using a weighted UniFrac distance matrix.ResultsSalt and water activity were different between brands (P ≤ 0.007). Brand A had less salt compared to brands B and C, while brand B had a lower water activity than brands A and C. Objective color values for L* and a* were not different (P ≥ 0.182) between brands or storage times, but b* was different between brands (P < 0.001). Brand A had greater b* (yellowness) than brands B and C. There was a brand by storage time interaction for pH (P = 0.021). At wk 0, the pH of brand B was lower than any time during the study. There was a significant main effect of brand on both APC and AnPC (P < 0.001). Brand A had greater APC and AnPC when compared to brands B and C. Observed OTUs and Chao1 diversity estimates indicated there was a brand by storage time interaction for bacterial richness, where brand A wk –4 had the greatest bacterial richness followed by brand A wk 0. There was a main effect of storage time on the bacterial community structure (P < 0.001). Brand B and brand C were more similar in community structure compared to brand A.ConclusionThe lower salt concentration in brand A may affect bacterial spoilage. Furthermore, results from this study indicate that the spoilage community associated with similar types of sliced ham is dependent on brand, implying that spoilage patterns and characteristics are related to environmental bacteria composition of the initial post-lethality contamination.

Antimicrobial Effect of Sage (Salvia officinalisL.) and Rosemary (Rosmarinus officinalisL.) Essential Oils on Microbiota of Chicken Breast

AbstractThe aim of the study was to evaluate the antimicrobial effect of sage and rosemary essential oils (EO) on microbiota of fresh chicken breast. Sample treatments were stored without packaging, vacuum-packaged, vacuum-packaged with EDTA 1.5% v/w, sage and rosemary EO treatment 0.2% v/w. Assessment of food quality was done by anaerobic plate count (APC), andEnterobacteriaceae, lactic acid bacteria (LAB) andPseudomonasspp. counts a period of 16 days of storage at 4 ± 0.5 °C. Bacterial species were identified with a MALDI TOF MS Biotyper. Antimicrobial activity of isolates against both EO were tested. The APC varied from 2.97 log CFU/g to 6.81 log CFU/g, LAB from 2.35 log CFU/g to 3.36 log CFU/g andEnterobacteriaceaefrom 0.00 log CFU/g on day 0 to 4.77 log CFU/g with the highest counts on day 16 and in control unpackaged samples.Pseudomonasspp. was found only on days 0, 4, 8, and 12, with counts from 0.00 log CFU/g on day 16 to 2.89 log CFU/g on day 4 in control unpackaged samples. APC were represented byStaphylococcusandKocuria, LAB withLactobacillusandEnterobacteriaceaewithButtiauxella,Escherichia,Hafnia,SerratiaandYersinia. ThePseudomonasgenus was represented by ten species. The best antimicrobial effect on APC,Enterobacteriaceae, LAB andPseudomonaswas achieved by application of EO. The results suggest the potential use ofSalvia officinalisL. andRosmarinus officinalisL. EOs as natural food preservatives and potential sources of antimicrobial ingredients in the food industry.

Microbiological quality of chicken breast meat after application of thyme and caraway essential oils

The aim of the present study was to evaluate the effect of selected types of antimicrobial essential oils to the various groups of microorganisms during storage of chicken meat. The samples of chicken breast meat were used in the experiment. The number of lactobacilli, Pseudomonas spp., anaerobic plate count and Enterobacteriaceae after application of caraway and thyme essential oils (EO) at concentration 1% v/w in a combination with the ethylenediaminetetraacetate (EDTA) solution 1.5% w/w and vacuum packaging were evaluated. The samples were analyzed at 0, 4th, 8th, 12th and 16th day of storage of chicken meat at temperature 4 °C. Another aim was to determine the species of isolated microorganisms from samples of chicken meat by MALDI-TOF MS Biotyper (matrix assisted laser desorption ionization-time of flight mass spectrometry). The number of Lactobalillus spp. ranged from 1.35 log CFU.g-1 in all groups to 3.04 log CFU.g-1 on 0th day to 3.04 log CFU.g-1 on 4th day in control group stored in air. The Pseudomonas spp. was not found in all tested samples at the start of the experiment, the highest number of Pseudomonas spp. was in the control group on 16th day (2.68 log CFU.g-1). Presence of Pseudomonas spp. were not found during storage in groups after treatment with caraway and thyme EO. The values of anaerobic plate count ranged from 2.81 log CFU.g-1 on 4th day in control group with vacuum packaging to 5.19 log CFU.g-1 on 16th day in control group in air condition. The Enterobacteriaceae was not found in all tested samples on 0th day and ranged to 4.46 log CFU.g-1 on 12th day in control group in air condition. From Lactobacillus spp., the most often identified species was Lactobacillus paracasei, from genus Pseudomonas, there were identified Pseudomonas fluorescens in two cases. From anaerobic plate count, there were isolated Staphylococcus warneri from control goup stored in air condition, Kocuria rhizophila from control group with vacuum packaging, Staphylococcus warneri, Aeromonas salmonicida and Aeromonas popoffii from control group treated with EDTA, Staphylococcus hominis and Staphylococcus epidermidis from group treated with caraway essential oil. From Enterobacteriaceae, the most bacteria were isolated from control group in air condition and from control group treated with EDTA.

The Effect of Salt Reduction on the Microbial Composition and Quality Characteristics of Sliced Roast Beef and Turkey Breast

ObjectivesThe objective of this study was to determine the effects of salt reduction on microbiological composition and quality characteristics of deli-style turkey breast and roast beef.Materials and MethodsSectioned and formed turkey breast and roast beef were manufactured with four different salt concentrations: 1.0, 1.5, 2.0, and 2.5% on a meat block basis. For three replicates, each treatment was vacuum tumbled for 1.5 h with the designated salt content plus 1.0% sugar and 0.35% sodium phosphate with the balance as water to achieve 25% extension. Turkey and beef samples were cooked to an internal temperature of 71°C, stabilized overnight, sliced, and vacuum packaged. On the day of slicing (wk 0), samples were evaluated for water activity, cook yield, proximate composition and percent salt. Starting on wk 0, samples were evaluated every 2 wk for pH, texture profile analysis (TPA), aerobic plate count (APC), and anaerobic plate count through 18 wk. From week 0 through 14, bacterial communities were analyzed by 16S rRNA gene sequencing using the Illumina Miseq system. Data were analyzed using the PROC GLIMMIX procedure of SAS (SAS Inst. Inc., Cary. NC). Means were separated using the LSMEANS PDIFF option with Tukey’s adjustment.ResultsThere was a species by salt interaction for APC (p = 0.009) where beef with 2.5% salt had the lowest counts, but was only different from beef with 2.0, 1.5, 1.0% and turkey with 2.5% salt. Aerobic plate count (p < 0.001) increased until wk 6 but did not significantly increase beyond. Family Pseudomonadaceae was the dominant flora on all samples, regardless of treatment or storage time. Relative abundance of Pseudomonadaceae was 46.4% of all sequences in beef samples and 36.0% in turkey samples at wk 0, followed by an increase at wk 2, and was statistically similar for the remainder of shelf life in both beef and turkey. Salt reduction negatively impacted cook yield (p < 0.001) and increased water activity (p < 0.001). Decreasing salt content reduced moisture (p = 0.026) and ash (p = 0.021), and increased protein (p < 0.001). Beef samples had a lower pH compared to turkey (p < 0.001), and 1.5% salt had a lower pH than all other treatments, regardless of species (p = 0.003). For all TPA measures except springiness, a salt by species interaction was identified (p < 0.002). In both beef and turkey, decreasing salt concentration increased hardness (p < 0.001). In beef, gumminess and cohesiveness increased as salt decreased. In turkey samples, the greatest gumminess and cohesiveness was observed with 1.5% salt, while 1.0 and 2.0% were less, and turkey with 2.5% salt had the least gumminess and cohesiveness. Beef samples with 1.0% salt had the greatest chewiness, followed by beef with 1.5% salt. Turkey samples with 2.5, 2.0, and 1.0% had the lowest chewiness values. As salt decreased, so did springiness (p < 0.001), and turkey samples had lower values than did beef samples (p < 0.001).ConclusionOur results show that bacterial population dynamics of cooked deli meat may be more dependent on initial population than parameters controlling growth such as salt concentration. Furthermore, reducing salt alters the textural properties of cooked deli meats and reduces cooking yields. At low salt concentrations, these negative effects are amplified in beef products compared to turkey.

The extension of shelf-life of chicken meat after application of caraway and anise essential oils and vacuum packaging

The effect of caraway (CEO) and anise (AEO) essential oils as well as vacuum packaging (VP) in extending of the shelf life of fresh chicken breast meat stored at 4 °C was investigated. CEO and AEO were used at concentrations 0.2% v/w with and without VP. Microbiological properties of chicken breast meat were monitored over a 16 day period. The microbiological parameters as the anaerobic plate count (AC), Enterobacteraceae, lactic acid bacteria and Pseudomonas spp. counts were detected. The anaerobic plate counts ranged from 2.77 log cfu.g-1 in all tested group on 0 day to 5.45 log cfu.g-1 on 16 day in control group stored in air condition. The number of lactic acid bacteria ranged from 3.20 log cfu.g-1 in all tested group on 0 day to 4.75 log cfu.g-1 on 16 day in control group stored in air condition. Enterobacteriaceae counts ranged from 0.00 to 4.25 log cfu.g-1on 16 day in control group stored in air condition. The number of Pseudomonas spp. ranged from 0.00 log cfu.g-1 in all tested group on 0 day to 2.65 log cfu.g-1 on 16 day in control group stored in air condition. Statistically significant differences (P≤0.001) were found among tested group in all tested microorganisms. Among the antimicrobial combination treatments were examined in the study, the as application of vacuum packaging, EDTA, and essential oils were the most effective against the growth of lactic acid bacteria and Enterobactericeae and to a less extent on anaerobic plate count. The results of this present study suggest the possibility of using the essential oil of caraway and anise as natural food preservatives and potential source of antimicrobial ingredients for chicken breast meat.

Microbiological quality of chicken thighs meat after four essential oils combination, EDTA and vaccum packing

The aim of the present work to monitoring chicken the microbiological quality of vaccum packaged thighs after treatment by ethylenediaminetetraacetate (EDTA), anise (Pimpinella anisum), spearmint (Mentha spicata var. crispa), thyme (Thymus vulgaris L.) oregano (Origanum vulgare L.) essential oils and stored in at 4 ±0.5 °C for a period of 16 days. The following treatments of chicken thighs were used: air-packaged control samples, control vacuum-packaged samples, vacuum-packaging with EDTA solution 1.5% w/w, control samples, vacuum-packaging after treatment with Pimpinella anisum, Mentha spicata var. crispa essential oil at concentrations 0.2% v/w, vacuum-packaging after treatment with Thymus vulgaris L., Origanum vulgare L. essential oil at concentration 0.2% v/w. The quality assessment of all samples was done microbiologically and following microbiological parameters were detected: the anaerobic plate count, Enterobacteraceae counts, lactic acid bacteria and Pseudomonas spp. counts. The number of anaerobic plate count ranged from 3.69 log CFU.g-1 in all tested group on 0 day to 5.68 log CFU.g-1 on 16 day in control group stored in air condition. The number of lactic acid bacteria ranged from 2.00 log CFU.g-1 in all tested group on 0 day to 4.82 log CFU.g-1 on 16 day in group with oregano, thyme essential oils combination. Enterobacteriacea counts in chicken thighs was 0.68 log CFU.g-1 on 0 day to 7.58 CFU.g-1 on 16 day in air-packed meat samples. The Pseudomonas spp. was not found in all tested samples. Among the antimicrobial combination treatments examined in this work, the as application of vacuum packaging, EDTA and essential oils treatment was the most effective against the growth of Enterobactericeae, inhibitory effect on anaerobic plate count also was observed. The results of this present study suggest the possibility of application the Pimpinella anisum, Mentha spicata var. crispa, Thymus vulgaris L., Origanum vulgare L. essential oil of as natural food preservatives and potential sources of antimicrobial ingredients for food industry for chicken thighs meat treatment.