scholarly journals Microbiological quality of beef stored under different modified atmospheres

2020 ◽  
Vol 76 (12) ◽  
pp. 6471-2020
Author(s):  
KATARZYNA ŚMIECIŃSKA
Keyword(s):  
Lactic Acid ◽  
Lactic Acid Bacteria ◽  
Microbial Growth ◽  
Microbiological Quality ◽  
The Other ◽  
Microbial Counts ◽  
Psychrotrophic Bacteria ◽  
Modified Atmospheres ◽  
Microbial Groups

The aim of this study was to analyze changes in the microbiological quality of Longissimus lumborum (LL) muscles collected from young Polish Holstein-Friesian Black-and-White (PHF BW) bulls and stored for 7, 14, and 21 days under different modified atmospheres (MA) (vacuum, 80% O2 + 20% CO2, 60% O2 + 30% CO2 + 10% N2, 40% CO2 + 60% N2, 30% CO2 + 70% Ar). Before and after the specified storage periods, crosssectional samples of the LL muscle were collected under aseptic conditions to determine total microbial counts, and the total counts of psychrotrophic bacteria and mesophilic lactic acid bacteria. The effects of storage time and MA composition on changes in the parameters analyzed were evaluated, and the effectiveness of argon in delaying microbial growth in cold-stored beef was determined. Between days 7 and 14 of storage, total microbial counts were lowest in meat packaged under the MA composed of 30% CO2 + 70% Ar, whereas between days 14 and 21 they were lowest in both MA packages containing O2. The greatest increase in total microbial counts between days 7 and 14 of storage was noted in the MAs containing O2, and between days 14 and 21 of storage in the MA containing Ar. Beef stored for 7 days in the MA containing 60% O2 was characterized by the lowest total microbial counts, whereas the highest total microbial counts were noted in samples stored for 14 days in the MA containing 80% O2. Between days 7 and 14 of storage, the counts of psychrotrophic bacteria increased significantly in all MAs. Between days 14 and 21 of storage, the counts of psychrotrophic bacteria did not increase in meat samples packaged under vacuum or the MA composed of 80% O2 + 20% CO2. The counts of psychrotrophs were significantly lower in beef stored for 7 days in the oxygen-free MAs than they were in both MA packages containing O2. The counts of psychrotrophic bacteria were significantly lower in beef stored for 14 days in the MA containing Ar, compared with samples packaged under vacuum and the MA containing 80% O2. Gas composition in MA packaging had no significant effect on total microbial counts or the counts of psychrotrophic bacteria in meat stored for 21 days. Between days 14 and 21 of storage, the counts of lactic acid bacteria did not increase significantly only in meat packaged in the MAs composed of 60% O2 + 30% CO2 + 10% N2 and 40% CO2 + 60% N2. After 7 days of storage, the counts of lactic acid bacteria were higher in beef packaged in oxygen-free MAs than they were in both MA packages containing O2. After 14 days of storage, the counts of lactic acid bacteria were higher in meat packaged in the MA composed of 80% O2 + 20% CO2 than they were in the other MAs. Beef samples stored for 21 days under the MA composed of 80% O2 + 20% CO2 were characterized by significantly lower counts of lactic acid bacteria, compared with samples stored under the other MAs, except for the MA composed of 40% CO2 + 60% N2. It can be concluded that beef can be stored in the MA composed of 30% CO2 + 70% Ar for shorter periods of time (up to 14 days). The modified atmosphere composed of 30% CO2 + 70% Ar contributed to slower microbial growth in meat and resulted in lower counts of psychrotrophs and lactic acid bacteria, relative to the other samples. However, there is a need for further research on different concentrations of argon in MA packages to confirm that this gas can effectively delay microbial growth in beef. Meat stored for 14 days in the MA composed of 80% O2 + 20% CO2 was characterized by the lowest microbiological quality. The composition of MAs had a minor influence on the growth rates of the microbial groups analyzed in beef stored for 21 days; certain changes were observed only in the counts of lactic acid bacteria.

Microbiological Quality and Production of Botulinal Toxin in Film-Packaged Broccoli, Carrots, and Green Beans

1999 ◽  
Vol 62 (5) ◽  
pp. 499-508 ◽  
Author(s):  
Y.-Y. HAO ◽  
R. E. BRACKETT ◽  
L. R. BEUCHAT ◽  
M. P. DOYLE
Keyword(s):  
Lactic Acid ◽  
Lactic Acid Bacteria ◽  
Gas Permeability ◽  
Microbiological Quality ◽  
Packaging Material ◽  
Green Beans ◽  
Psychrotrophic Bacteria ◽  
Anaerobic Microorganisms ◽  
Yeasts And Molds

The production of toxin by a 10-strain mixture of proteolytic Clostridium botulinum in fresh produce packaged in polyethylene films with different oxygen permeability was determined. Broccoli florets, shredded carrots, and green beans inoculated with approximately 102 C. botulinum spores per g were placed in bags (1.4 kg per bag) composed of four films with different oxygen transmission rates (OTRs). Broccoli was packaged in bags with OTRs of 3 (7,000 cm3/m2/24 h) and 4 (16,000 cm3/m2/24 h), and green beans were packaged in bags with OTRs of 2 (6,000 cm3/m2/24 h) and 4. Broccoli and green beans in bags were compressed and heat-sealed. Shredded carrots were packaged in bags with OTRs of 1 (3,000 cm3/m2/24 h) and 3 and vacuum-sealed. Produce was stored at 4, 13, and 21°C for up to 27 (broccoli) or 28 (carrots and green bean) days and analyzed periodically. At each sampling time, gas composition within the bags, pH of the produce, microbial populations (total aerobic and anaerobic microorganisms, lactic acid bacteria, psychrotrophic bacteria, yeasts, and molds), and the presence or absence of botulinal toxin were determined. Packaging material affected the quality of vegetables, especially broccoli stored at 4 and 13°C. For example, broccoli was scored as “good” after 22 days at 4°C when it was packaged in film with higher gas permeability (OTR of 4), whereas broccoli appeared to be in “poor” condition when packaged in film with lower gas permeability (OTR of 3). With the exception of lactic acid bacteria, packaging material did not noticeably influence the growth of microorganisms. Lactic acid bacteria grew better in broccoli packaged in bags with an OTR of 3 than in those with an OTR of 4 at all temperatures. Botulinal toxin was detected in broccoli packaged in bags with an OTR of 3 and stored at 13°C for 21 days and in those with an OTR of 4 and 3 and stored at 21°C for 10 days. All toxic samples were visibly spoiled. Toxin was not detected in produce packaged under any other test conditions.

scholarly journals Hardening Properties of Cheeses by Latilactobacillus curvatus PD1 Isolated from Hardened Cheese-Ddukbokki Rice Cake

2021 ◽  
Vol 9 (5) ◽  
pp. 1044
Author(s):  
Jeong A Kim ◽  
Geun Su Kim ◽  
Se Mi Choi ◽  
Myeong Seon Kim ◽  
Do Young Kwon ◽  
...  
Keyword(s):  
Lactic Acid ◽  
Lactic Acid Bacteria ◽  
Acid Production ◽  
Lactobacillus Casei ◽  
Leuconostoc Mesenteroides ◽  
The Other ◽  
Rice Cake ◽  
Two Samples ◽  
High Protease Activity

Hardening of cheese is one of major issues that degrade the quality of Home Meal Replacement (HMR) foods containing cheese such as Cheese-ddukbokki rice cake (CD, stir-fried rice cakes with shredded cheese). The quality of cheese, such as pH, proteolytic, and flavor properties, depends on various lactic acid bacteria (LAB) used in cheese fermentation. The hardening of cheese is also caused by LAB. In this study, various LAB strains were isolated from CD samples that showed rapid hardening. The correlation of LAB with the hardening of cheese was investigated. Seven of the CD samples with different manufacturing dates were collected and tested for hardening properties of cheese. Among them, strong-hardening of cheese was confirmed for two samples and weak-hardening was confirmed for one sample. All LAB in two strong-hardening samples and 40% of LAB in one weak-hardening sample were identified as Latilactobacillus curvatus. On the other hand, most LAB in normal cheese samples were identified as Leuconostoc mesenteroides and Lactobacillus casei. We prepared cheese samples in which L. curvatus (LC-CD) and L. mesenteroides (LM-CD) were most dominant, respectively. Each CD made of the prepared cheese was subjected to quality test for 50 days at 10 °C. Hardening of cheese with LC-CD dominant appeared at 30 days. However, hardening of cheese with LM-CD dominant did not appear until 50 days. The pH of the LC-CD was 5.18 ± 0.04 at 30 days, lower than that of LM-CD. The proteolytic activity of LC-CD sample was 2993.67 ± 246.17 units/g, higher than that of LM-CD sample (1421.67 ± 174.5 units/g). These results indicate that high acid production and high protease activity of L. curvatus might have caused hardening of cheese.

Microbiological Quality of Commercial Tofu

1984 ◽  
Vol 47 (3) ◽  
pp. 177-181 ◽  
Author(s):  
T. G. REHBERGER ◽  
L. A. WILSON ◽  
B. A. GLATZ
Keyword(s):  
Microbiological Quality ◽  
Plate Count ◽  
Microbial Counts ◽  
Colony Forming Units ◽  
Low Levels ◽  
Microbial Groups ◽  
Yeasts And Molds ◽  
Processing Techniques

A study was done to investigate the microbiological quality of commercial tofu available in local retail outlets. A sampling method was first developed to obtain accurate and representative microbial counts of individual pieces of tofu. Plate count determination of total aerobic organisms, psychrotrophs, coliforms, sporeformers, yeasts and molds, and staphylococci were made on 60 tofu samples (representing three lots each of four different brands) obtained within 24 h after delivery to the retail store. In addition, for two brands that provided manufacturer's pull dates, the same microbial counts were obtained for samples stored in the laboratory at 10°C until the pull date. Of the tofu sampled immediately after purchase, 83% of the lots tested had total counts greater than 106 colony-forming units (CFU)/g and psychrotrophic counts greater than 104 CFU/g. In addition, 67% of the lots tested had confirmed coliform counts greater than 103 CFU/g. Very low levels (less than 10 CFU/g) of all other microbial groups tested for were found in the majority of lots. Samples held until the manufacturer's pull date contained higher total and psychrotrophic counts but lower or stable counts of other organisms compared with samples tested immediately after purchase. To improve the microbiological quality of tofu, processors need to reduce initial loads by improving sanitation and processing techniques, and retailers should provide more consistent and colder refrigerated storage.

scholarly journals Tokat Bez Sucuğunun Mikrobiyolojik Kalitesinin İncelenmesi

2020 ◽  
Vol 8 (12) ◽  
pp. 2683-2694
Author(s):  
Nesrin Kaval ◽  
Nilgün Öncül ◽  
Zeliha Yıldırım
Keyword(s):  
Lactic Acid ◽  
Lactic Acid Bacteria ◽  
Fecal Coliform ◽  
Microbiological Quality ◽  
Total Coliform ◽  
Aerobic Bacteria ◽  
Escherichia Coli O157 ◽  
Salmonella Spp ◽  
Microbiological Parameters

In this study, the microbiological quality of traditionally produced Bez Sucuk in Tokat and its vicinity was investigated. For this purpose, 30 Bez Sucuk samples obtained from butchers, producers of Bez Sucuk, were analyzed for total count of mesophilic aerobic bacteria, lactic acid bacteria, yeasts-moulds, total coliform, fecal coliform, Staphylococcus aureus, Bacillus cereus, and Cl. perfringens. Also, the presence of Escherichia coli O157:H7, Listeria monocytogenes and Salmonella spp. were investigated in all samples. pH and water activity of the samples were determined. As the result of the analysis, the counts of the microbiological parameters investigated were found as follows: total mesophilic aerobic bacteria 3.5×106-4.23×109 CFU/g, lactic acid bacteria 5.55×105-2.45×109 CFU/g, yeasts and moulds 2.50×103-6.90×109 CFU/g, total coliform

Chemical and Microbiological Quality of Raw Milk Produced by Smallholder Farmers in Zimbabwe

1996 ◽  
Vol 59 (9) ◽  
pp. 984-987 ◽  
Author(s):  
A. N. MUTUKUMIRA ◽  
S. B. FERESU ◽  
J. A. NARVHUS ◽  
R. K. ABRAHAMSEN
Keyword(s):  
Lactic Acid ◽  
Lactic Acid Bacteria ◽  
Smallholder Farmers ◽  
Microbiological Quality ◽  
Titratable Acidity ◽  
Raw Milk ◽  
Chemical Characteristics ◽  
Yeasts And Molds ◽  
Microbiological Analyses

Chemical and microbiological analyses were carried out on 10 samples of raw milk collected over 6 months from the Nharira/Lancashire Milk Collection Center. The milk center is run by smallholder farmers. The purpose of the study was to evaluate the quality of the raw milk delivered to the milk collection center. The average chemical characteristics of the milk were (%): titratable acidity expressed as lactic acid, 0.21; total protein, 3.19; fat, 3.52; total solids, 11.76; and solids not fat, 8.25; the pH varied from 6.15 to 6.65. There were large variations in the microbiological composition of the raw milk with total aerobic counts ranging from 6.2 × 103 to 7.8 × 107 CFU/ml, coli forms from 3.2 × 102 to 2.3 × 105, and lactic acid bacteria from less than 1 × 103 to 2.9 × 106 CFU/ml. Yeasts and molds were less than 100 CFU/ml in 7 of the 10 samples analyzed.

Sodium Lactate Addition on the Quality and Shelf Life of Refrigerated Sliced Poultry Sausage Packaged in Air or Nitrogen Atmosphere

2004 ◽  
Vol 67 (3) ◽  
pp. 601-606 ◽  
Author(s):  
RENATA CEGIELSKA-RADZIEJEWSKA ◽  
JAN PIKUL
Keyword(s):  
Lactic Acid ◽  
Lactic Acid Bacteria ◽  
Shelf Life ◽  
Sodium Lactate ◽  
Life Extension ◽  
Poultry Meat ◽  
Color Measurement ◽  
Refrigerated Storage ◽  
Psychrotrophic Bacteria

The aim of this study was to determine the effect of sodium lactate addition on shelf-life extension of sliced poultry sausage packaged both in air and nitrogen atmospheres and stored in refrigerated conditions. Basic chemical composition, pH, and malonaldehyde content were assayed and color measurement using the reflection method was carried out. Microbiological examination consisted of determination of total number of aerobic psychrotrophic bacteria and number of lactic acid bacteria. Sensory evaluation of products was performed. Microbiological and sensory quality of sliced poultry meat sausage was dependent on the addition during production of sodium lactate and the composition of gases (air or nitrogen) used in packaging. Slices of poultry sausage with 1% as well as 2% of sodium lactate maintained their initial quality of evaluated sensory attributes longer, irrespective of the applied gases. Sodium lactate inhibited growth of aerobic psychrotrophic bacteria and lactic acid bacteria during refrigerated storage. Sodium lactate also inhibited the formation of malonaldehyde in sliced poultry sausage during refrigerated storage. The effectiveness of this process depended on the concentration of sodium lactate addition. It was concluded that 1% as well as 2% addition of sodium lactate could extend the shelf life of sliced poultry sausage packaged in air atmosphere and stored at 5 to 7°C by 3 or 4 times, respectively. Sliced poultry sausage treated with 2% sodium lactate packed in nitrogen had the longest (35-day) shelf life. This was a sevenfold increase in the shelf life of sliced poultry sausage compared with the control.

Antimicrobial Effect of Medicinal Plants on Microbiological Quality of Grape Juice

2021 ◽  
Vol 5 (1) ◽  
pp. 28-35
Author(s):  
Miroslava Kačániová ◽  
Jakub Mankovecký ◽  
Lucia Galovičová ◽  
Petra Borotová ◽  
Simona Kunová ◽  
...  
Keyword(s):  
Lactic Acid ◽  
Lactic Acid Bacteria ◽  
Medicinal Plants ◽  
Control Sample ◽  
Microbiological Quality ◽  
Grape Juice ◽  
Coliform Bacteria ◽  
Cabernet Sauvignon ◽  
Microscopic Fungi

Abstract The safety of plant-based food of plant origin is a priority for producers and consumers. The biological value of food products enriched with herbal ingredients is getting more popular among consumers. The present study was aimed to evaluate microbiological quality of grape juice enriched with medicinal plants. There were two varieties of grapes -Welschriesling and Cabernet Sauvignon and six species of medicinal plants used for the experiment: Calendula officinalis L., Ginkgo biloba, Thymus serpyllum, Matricaria recutita, Salvia officinalis L., and Mentha aquatica var. citrata. A total of 14 samples of juice were prepared and two of them were used as controls and 12 samples were treated with medicinal plants. Total microbial count, coliforms, lactic acid bacteria and yeasts and microscopic fungi for testing the microbiological quality were detected. All the samples were negative for lactic acid bacteria. There were neither coliform bacteria nor yeast and fibrous microscopic fungi present in some of the treated samples apart from the control samples. Coliform bacteria of 1 log cfu/mL were detected during the first testing and identified Proteus vulgaris in the control sample of grape juice of the variety Welschriesling. The yeast of the genus Candida was present in 2 log cfu/mL and it was detected during first and second testing in the control sample of Cabernet Sauvignon, unlike the other samples. The sample of grape juice with the addition of sage had the most significant inhibitory effect on total count of bacteria. The most common microorganisms in all samples were Bacillus cereus and Acinetobacter johnsonii, however, those microorganisms were absent during second testing due to the action of naturally occurring antimicrobials in the grapes.

Microbiological Quality of Beef Subprimals as Affected by Lactic Acid Sprays Applied at Various Points during Vacuum Storage

1997 ◽  
Vol 60 (7) ◽  
pp. 795-798 ◽  
Author(s):  
R. K. PRASAI ◽  
C. L. KASTNER ◽  
P. B. KENNEY ◽  
D. H. KROPF ◽  
D. Y. C. FUNG ◽  
...  
Keyword(s):  
Lactic Acid ◽  
Storage Temperature ◽  
Microbiological Quality ◽  
Storage Period ◽  
Microbial Counts ◽  
Before And After ◽  
Main Effects ◽  
Vacuum Storage ◽  
Spray Treatment

Beef strip loins were sprayed with 1.5% (vol/vol) lactic acid before and/or after 14, 28, 56, 84, and 126 days of vacuum-packaged storage at −1.1 or 2°C to assess the effects on bacteria. Five different treatment combinations including a control (no spray treatment) and one treatment with prestorage acid spray followed by poststorage water spray (A/W) were evaluated. Compared to the controls, 97% of all acid-treated loins had lower microbial counts throughout the storage period. Prestorage acid spray (A/0) was more effective than poststorage acid spray (0/A)with the greatest effects (P < 0.05) being observed on day 28, where the bacterial population was reduced by 1.9 and 1.5 log CFU/cm2 for loins stored at −1.1 and 2°C, respectively. Microbial counts for loins with A/A(acid spray both before and after vacuum storage) or A/W treatments were lower than but not significantly different from A/0 (P > 0.05). Poststorage washing resulted in a minimal decontaminating effect, irrespective of the washing agent used. In addition, single spray treatment immediately after fabrication seems more effective and practical than a double spray. Temperature main effects showed that colder temperature (−1.1 versus 2°C) reduced (P < 0.03) microbial growth throughout the storage period. Salmonella contamination was not detected in any samples; however, 28% of the control and 4% of the spray-treated loins were positive for Listeria spp. Appropriate time of acid application in combination with colder storage temperature improved the microbiological quality of meat for at least four weeks.

Bioconversion of Discard Fish (Equulites klunzingeri and Carassius gibelio) Fermented with Natural Lactic Acid Bacteria; the Chemical and Microbiological Quality of Ensilage

2018 ◽  
Vol 11 (4) ◽  
pp. 1435-1442
Author(s):  
Caner E. Ozyurt ◽  
Esmeray Kuley Boga ◽  
Ali Serhat Ozkutuk ◽  
Yılmaz Ucar ◽  
Mustafa Durmus ◽  
...  
Keyword(s):  
Lactic Acid ◽  
Lactic Acid Bacteria ◽  
Microbiological Quality ◽  
Carassius Gibelio
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