scholarly journals Application of Natural Antimicrobial Additives and Protective Culture to Control Aerobic Spore Forming Bacteria in Low Salt Soft Cheese

2020 ◽  
Vol 10 (4) ◽  
pp. 609-616
Author(s):  
Eman K. Abo Shaala ◽  
Sameh A. Awad ◽  
Ashraf M. Nazem
Keyword(s):  
Antimicrobial Agents ◽  
Lactobacillus Rhamnosus ◽  
Microbiological Quality ◽  
Storage Period ◽  
Life Extension ◽  
Natural Antimicrobial ◽  
Soft Cheese ◽  
Low Salt ◽  
Protective Culture ◽  
Spore Forming Bacteria

There is an increasing interest in the application of natural antimicrobials instead of chemical ones to enhance the microbiological quality of dairy products. The objective of this study was to assess the effect of some natural antimicrobial additives and protective culture for reducing the usage of chemical preservatives, shelf-life extension, retarding microbial spoilage in low-salt soft cheese. The antimicrobial agents (protective culture, nisin, lysozyme, and natamycin) were studied on the activity of 28 isolates of spore-forming bacteria. Inhibitory effect of different natural antimicrobial additives as protective culture (Lactobacillus rhamnosus, 40 mg kg -1), nisin (25 mg kg -1), lysozyme (100 mg kg -1), combination of nisin and lysozyme (25 mg kg -1/100 mg kg -1), and combination of protective culture and natamycin (40 mg kg -1/25 mg kg -1) were studied on the growth of aerobic spore-forming bacteria in low-salt soft cheese during the storage period (30 days) at 4±1°C. The results revealed that the addition of different natural antibacterial additives with various concentrations had a significant effect on aerobic spore-forming bacteria, compared to other treatments and control. The growth pattern of aerobic spore-forming bacteria gradually decreased in all treatments along the storage period with variable reduction percentages in comparison with control cheese which was in continuous increment. The application of a combination of nisin and lysozyme had the most significant reduction of aerobic spore-forming bacteria, compared to control and other treatments.

scholarly journals The combined effect of bacteriocin-producing Lactobacillus rhamnosus GG-ATCC and Lactoperoxidase system activation on microbiological quality of raw milk with special emphasis against E.coli O157:H7 in milk

2017 ◽  
Vol 40 (2) ◽  
pp. 66-72
Author(s):  
Najim Hadi Najim
Keyword(s):  
Storage Temperature ◽  
Lactobacillus Rhamnosus ◽  
Microbiological Quality ◽  
Raw Milk ◽  
Latex Agglutination ◽  
Bacterial Cells ◽  
Lactobacillus Rhamnosus Gg ◽  
Time Period ◽  
Soft Cheese ◽  
Chromogenic Agar

     Isolates of Enterohaemorrhagic E.coli O157:H7 were isolated from 51 and 41 of locally produced bovine and ovine soft cheese samples. Their identification were confirmed based on the biochemical reactions and both the morphological cultural and serological properties. Presumptive E.coli O157:H7 isolates obtained by using the conventional selective plating on the chromogenic agar were tested further for the presence of both O157 and H7 antigenes using the latex agglutination test antisera. The current microbiological studies revealed that 31 (33.70 %) out of 92 bovine and ovine soft cheese samples were positive for E.coli O157:H7. The highest non significant (P>0.05) prevalence level of E.coli O157:H7 was found in the ewe᾿s soft cheese samples (36.59 %) followed by cow᾿s soft cheese samples (31.37 %). Agar well diffusion bioassay method was used for measuring the antibacterial activity of the crude bacteriocin that was produced by Lactobacillus rhamnosus GG-ATCC against Escherichia coli and the closely related sensitive strains such as L.acidophilus LA-K and L.acidophilus ROO52. The crude bacteriocin that was produced by the L.rhamnosus GG-TACC exhibited significantly (P<0.05) the highest antibacterial potency (100 %) against both the closely related strains of lactobacilli and the stressed E.coli O157:H7 by the activation of the LPS. The activation of the natural LPS of inoculated pasteurized milk had significantly (P<0.05) influenced the inactivation degree of the crude bacteriocin against E.coli O157:H7. There was a significant (P<0.05) reduction in the viable counts of stressed E.coli O157:H7 after each exposure time period (6, 24 and 48 hrs.) to the crude bacteriocin at room storage temperature. An overall conclusion on the basis of the current results pointed  out  that complete  elimination of viable bacterial cells was not achieved  neither  in  the stabilized milk (Activation of LPS) nor after  subjecting  the stabilized  milk to the action of the crude bacteriocin produced by L.rhamnosus GG-ATCC at room storage temperature.

scholarly journals Effect of Ziziphus spina-christi and Cinnamomum zeylanicum essential oils on the microbiological quality of braided cheese during the storage period

2021 ◽  
Vol 7 (2) ◽  
pp. 001-008
Author(s):  
Abdulaziz Yahya Al-Ghamdi ◽  
Hanady Abdelateef Abdalla Khalefa ◽  
Mohamed Osman Mohamed Abdalla
Keyword(s):  
Essential Oils ◽  
Antimicrobial Agents ◽  
Starter Culture ◽  
Microbiological Quality ◽  
Storage Period ◽  
Raw Milk ◽  
Cow Milk ◽  
Coliform Bacteria ◽  
Cinnamomum Zeylanicum ◽  
Viable Bacteria

The purpose of this study was to understand how the addition of Ziziphus spina–christi and Cinnamomum zeylanicum essential oils as antimicrobial agents affect the microbiological properties of braided cheese. Cheese was made from warmed (45℃) raw cow milk to which essential oils of Z. spina–christi and C. zeylanicum (0.3% and 0.5%) were added. Microbiological characteristics were determined at 1, 7, 14 and 21-day intervals. The essential oils of Z. spina–christi and C. zeylanicum significantly reduced the counts of total viable bacteria (TVB), coliform bacteria, S. aureus, yeasts and moulds in cheese supplemented with the oils compared to the control cheese. As the concentration of oil increased, the number of microbes decreased. The storage period had a significant effect on the microbial counts in both the control cheese and the cheese supplemented with essential oils of Z. spina–christi and C. zeylanicum. The addition of the oils as preservatives to the braided cheese was effective against microbial populations and could be used in cheese preparations to extend the shelf life of cheese, particularly for cheese made from raw milk without the addition of starter culture.

scholarly journals The combined action of the Nisin and Lactoperoxidase system activation on the microbiological quality of raw milk with special emphasis against E.coli O157H7 in milk

2017 ◽  
Vol 40 (2) ◽  
pp. 61-65
Author(s):  
Zina Saab Khudhir
Keyword(s):  
Microbiological Quality ◽  
Storage Period ◽  
Raw Milk ◽  
Lactobacillus Strain ◽  
Lactoperoxidase System ◽  
Test Kit ◽  
Soft Cheese ◽  
C 30 ◽  
Refrigeration Storage ◽  
Antimicrobial Potency

         Escherichia coli O157:H7 were isolated from 90 bovine and ovine locally produced soft cheese samples and their identification were confirmed based on the cultural, biochemical reactions and serological properties, E.coli O157:H7 isolates obtained by plating on the Chromogenic agars. They were further tested serologically for the presence of both O157 and H7 antigenes using the agglutination test kit. The highest non-significant prevalence (P>0.05) level of E.coli O157:H7 was found in the ewe’s soft cheese samples (37.77%) followed by the cow’s soft cheese samples (31.11%). The antimicrobial potency of the Nisin against the sensitive Lactobacillus strain was lost after (10) minutes of heating at (80°C) while retaining (100%) of its antimicrobial potency after its exposure to the pasteurization time and temperature (63°C/ 30 min.). The highest antimicrobial potency of Nisin was achieved at neutral pH (100%) while 90% and 45% of its potency were retained under acidic (pH=3) and alkaline (pH=9) conditions respectively. Nisin had short bacteriocidal incubation period against the sensitive lactobacillus strain where its antimicrobial potency reduced after 48 hours and lost after 120 hours of refrigeration storage period. E.coli O157:H7 was insensitive to the action of Nisin while stressed E.coli O157:H7 by activation of lactoperoxidase system in pasteurized milk was susceptible to its action and such result gave an indication of the synergistic effect of Nisin with activated lactoperoxidase system.

scholarly journals Inhibitory activity of some functional cultures toward common microbial contaminants in soft cheese manufactured from raw milk

2020 ◽  
Vol 6 (10) ◽  
pp. 43-49
Author(s):  
Ahmed M. M. Mabrouk
Keyword(s):  
Inhibitory Activity ◽  
Storage Period ◽  
Raw Milk ◽  
Fecal Coliforms ◽  
Control Treatment ◽  
Total Coliforms ◽  
Soft Cheese ◽  
Microbial Contaminants ◽  
Microbial Groups ◽  
Spore Forming Bacteria

The inhibitory activity of Lb. plantarum NRC AM10, Lb. curvatus NBIMCC 3452, Lb. paracasei NRRL B-4560 and Lb. gasseri NRRL B-14168 were investigated against the microbial contaminants in raw milk soft cheese. Cultures were added at the level of 5 % in T1, T2, T3 and T4 respectively, and the control treatment made without starters. Microbial counts in raw milk sample showed 10.25, 6.85, 5.89, 4.76, 4.42, 4.44, 3.77, 3.64 and 3.46 log cfu/ml for total viable count, total coliforms, Staphylococci, moulds and yeasts, Enterococci, fecal coliforms, spore forming bacteria, psychrotrophic and Salmonella respectively. Some of microbial groups in control cheese were increased in the first 5 days of storage and others were increased until 10 days then all microbial groups were gradually decreased with extending storage period. Staphylococci reached to the lowest counts 3.11 log cfu/ml after 20 days, on contrast moulds and yeasts reached to the highest count 5.22 log cfu/ml at the end of storage period. The inhibition rate % (IR) were influenced by the variety of strain added in cheese treatments and the highest IR 32.58 and 33.96 % against total coliforms and Enterococci were recorded in the treatment containing Lb. plantarum NRC AM10 while the highest IR 25.84 % against fecal coliforms was recorded in the treatment containing Lb. curvatus NBIMCC 3452. Meanwhile, the IR 35.19 and 15.84 % were recorded against Salmonella and spore forming bacteria with strain Lb. gasseri NRRL B-14168. The strain Lb. paracasei NRRL B-4560 showed IR 42.23 and 44.4 % against Staphylococci and psychrotrophic respectively. Moulds and yeasts talked a revers trend of IR because of increasing the counts by acidity development. In conclusion, the only addition of functional cultures to control the growth and survival of pathogens in raw milk products is not enough to produce safe product. Use of pasteurized milk, good hygienic and good manufacturing practices are essential to reduce the risk of microbial contamination and health hazards in dairy products.

scholarly journals Heat shock and salicylic acid on postharvest preservation of organic strawberries

Revista CERES ◽  
2014 ◽  
Vol 61 (3) ◽  
pp. 306-312
Author(s):  
Sidiane Coltro ◽  
Laline Broetto ◽  
Maria Cristina Copelo Rotilli ◽  
Alice Jacobus de Moraes ◽  
Fabiane Karine Barp ◽  
...  
Keyword(s):  
Weight Loss ◽  
Salicylic Acid ◽  
Heat Shock ◽  
Good Condition ◽  
Microbiological Quality ◽  
Storage Period ◽  
Defense Responses ◽  
Life Extension ◽  
Fresh Weight ◽  
And Control

Heat shock and salicylic acid have been studied on shelf-life extension of fruits. The benefits of these techniques have been related to their effect on inducing physiological defense responses against the oxidative stress and pathogen development. The objective of this study was to evaluate the effect of heat shock and salicylic acid on the postharvest preservation and contents of total phenolics, anthocyanins, ascorbic acid, fresh weight loss and microbiological quality of organic strawberries cv. Dover. Strawberries produced organically and stored at 5 ºC were subjected to heat shock (45 ºC ± 3 ºC for 3 h), application of salicylic acid (soaking in 2.0 mmol L-1 solution), heat shock in combination with salicylic acid and control. After treatment, the fruits were packed and stored in a climatic chamber at 5 ºC ± 2 ºC. At 1, 7 and 14 days, the experimental units were removed from refrigeration and kept at room temperature of approximately 20 ºC for two days. There was no effect of treatments on fresh weight loss, incidence of pathogens or chemical variations in strawberry fruits during the storage period. In natural conditions, organically grown strawberries remained in good condition for sale up to seven days of storage in all treatments.

scholarly journals Quality and shelf-life extension of refrigerated (4°C) Spotted snakehead (Channa punctata) using γ-radiation and food-grade preservative

2021 ◽  
Vol 9 (1-2) ◽  
pp. 1-12
Author(s):  
Efat Ara Mou ◽  
Md Enamul Haque ◽  
Arzina Hossain ◽  
Mahfuza Islam ◽  
Md Kamruzzaman Munshi ◽  
...  
Keyword(s):  
Gamma Radiation ◽  
Shelf Life ◽  
Microbiological Quality ◽  
Storage Period ◽  
Life Extension ◽  
Potassium Sorbate ◽  
Control Panel ◽  
Channa Punctata ◽  
Food Grade ◽  
Shelf Life Extension

Investigations were carried out to evaluate the effect of gamma radiation (1.0 and 1.5 kGy) and food-grade preservative (2% potassium sorbate) on the shelf-life of refrigerated (4°C) Spotted snakehead, Channa punctata (Bloch, 1793). Quality assessments were evaluated by sensory (OS), chemical (TV), microbial (TBC and TCC) analyses. Based on control panel, OS was shown to be gradually decreased with the storage time. Irradiated and potassium sorbate treated samples were found acceptable (edible) up to 28 and 21 days, respectively of storage period. TV were lower in irradiated samples with dose of 1.5 kGy compared to other samples. Though microbial load of each of the irradiated samples were within the acceptable limits up to 28 days but 1.5 kGy dose was found more effective. Gamma radiation in combination with good refrigeration could be most effective treatment for the shelf-life extension and microbiological quality improvement for snakehead preservation. Moreover, this preservation technique may be applicable for other fish species to enhance food safety for public health issues. Jahangirnagar University J. Biol. Sci. 9(1 & 2): 1-12, 2020 (June & December)

scholarly journals Effect of selected starter cultures on production, properties and shelf life of fresh type cheese

2020 ◽  
Vol 15 (3-4) ◽  
Author(s):  
Irena Barukčić ◽  
Marta Keškić ◽  
Katarina Lisak Jakopović ◽  
Sven Karlović ◽  
Rajka Božanić
Keyword(s):  
Shelf Life ◽  
Milk Fat ◽  
Microbiological Quality ◽  
Storage Period ◽  
Sensory Properties ◽  
Starter Cultures ◽  
Number Of Microorganisms ◽  
Fresh Cheese ◽  
Protective Culture ◽  
Entire Storage Period

The aim of this study was to examine the influence of different starter cultures including protective culture on the production and properties of fresh cheese. Fresh cheeses were produced from pasteurized milk by adding mesophilic starter cultures, mesophilic cultures and liquid rennet and by adding protective culture. All samples were analysed for acidity (active and titratable), microbiological quality, texture, colour and sensory properties during 21 days of cold storage. Additionally, milk fat, the total dry matter, total proteins and mineral content were determined in all cheese samples on the first day of storage. It could be observed that the used mesophilic culture in general did not affect chemical composition of cheese. As expected, during the storage period acidity in all cheeses decreased, while the number of microorganisms increased, whereby that changes were significantly slowed down in cheese produced by adding protective culture. Scores of sensory evaluation were high during the entire storage period for all cheeses, but samples containing and cheese protective cultures achieved the highest score (18.56) at the first as well as at the last day of storage (17.98). According to all analyses, it is evident that the shelf life of cheese produced by adding protective culture has been prolonged for 12 days in comparison to samples produced without protective culture, and accounted 21 days when properly cool stored. In conclusion, the addition of protective culture might be useful for extending the shelf life and maintaining sensory properties as well as colour of fresh cheese.

scholarly journals Effects of vacuum and modified atmosphere packaging on the biochemical and microbiological quality of sliced goonch fish (Bagarius bagarius) stored at refrigerated condition

Food Research ◽  
2020 ◽  
Vol 4 (6) ◽  
pp. 2256-2264
Author(s):  
E.J. Alice ◽  
M. Amanullah ◽  
M.A. Karim ◽  
M.A. Hossain ◽  
M.T. Islam
Keyword(s):  
Shelf Life ◽  
Promising Result ◽  
Control Sample ◽  
Modified Atmosphere Packaging ◽  
Microbiological Quality ◽  
Storage Period ◽  
Thiobarbituric Acid ◽  
Life Extension ◽  
Modified Atmosphere

Vacuum packaging and modified atmosphere packaging (MAP) are widely applied packaging methods for displaying refrigerated fish and fish products. This study evaluated the biochemical and microbiological quality of sliced goonch fish (Bagarius bagarius) by analysing different parameters under not sealed pack (control), vacuum pack, and MAP-1 (50% CO2 / 50% N2), and MAP-2 (50% CO2 / 50% O2) at three days interval in 15 days of refrigerated storage at 4±1°C. The total volatile base nitrogen (TVB-N), peroxide value (PV) and thiobarbituric acid reactive substances (TBARS) values of the samples in four packaging systems did not cross the acceptable limit in the entire storage time. The total viable count (TVC) progressively increased with time in all packaging systems. However, TVCs were significantly (p<0.05) lower on 9th and 12th storage day in all samples compared to the control sample. Based on the bacterial counts of 7 log CFU/g, the shelflife was determined at about 6, 10, 12, and 9 days for control, vacuum, MAP-1, and MAP2 sample, respectively. All treatments offered satisfactory results during the storage period, except for the control in terms of shelf life. However, MAP-1 with 50% CO2 and 50% N2 demonstrated the promising result for shelf life extension, which can be utilised by the retail superstores for displaying the fishes.

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