Microbiological Characteristics and Shelf Life of Corn Tortillas with and without Antimicrobial Agents

1988 ◽  
Vol 51 (12) ◽  
pp. 945-948 ◽  
Author(s):  
A. TELLEZ-GIRON ◽  
G. R. ACUFF ◽  
C. VANDERZANT ◽  
L. W. ROONEY ◽  
R. D. WANISKA
Keyword(s):  
Shelf Life ◽  
Antimicrobial Agents ◽  
Plate Count ◽  
Refrigerated Storage ◽  
Microbiological Characteristics ◽  
Airborne Contamination ◽  
Aerobic Plate Count ◽  
Mold And Yeast ◽  
Sanitary Conditions ◽  
Corn Tortillas

Commercial corn tortillas were assayed for pH, moisture, aw, aerobic plate count (APC) and mold and yeast count (MYC). The shelf life of commercial tortillas ranged from 3 to 60 days, depending on the amount and type of preservative added. High initial APCs of commercial tortillas were associated with poor sanitary conditions at the plants, airborne contamination and improper storage practices. Shelf life of tortillas was greatly enhanced by refrigerated storage with or without the use of antimicrobials. For tortillas stored at 25°C, substantial increases in shelf life were attained by acidification (0.45% fumaric acid) plus addition of K-sorbate or Ca-propionate, but particularly by combination of these two antimicrobials. For tortillas stored at 4°C, shelf life of non-acidified samples was somewhat enhanced by addition of parabens and combinations of K-sorbate and Ca-propionate. Shelf life of acidified tortillas at 4°C was somewhat enhanced by addition of parabens and K-sorbate but increased substantially by addition of Ca-propionate and combinations of K-sorbate and Ca-propionate.

scholarly journals Effect of antimicrobial agents on some chemical and microbiological characteristics of vacuum: Packaged ground buffalo meat stored under refregerated condition

2009 ◽  
Vol 25 (3-4) ◽  
pp. 231-239 ◽  
Author(s):  
M.A. Kenawi ◽  
Abdel Salam ◽  
M.N. Kenawi
Keyword(s):  
Sodium Chloride ◽  
Shelf Life ◽  
Antimicrobial Agents ◽  
Storage Period ◽  
Bacterial Count ◽  
Sodium Lactate ◽  
Plate Count ◽  
Buffalo Meat ◽  
Microbiological Characteristics ◽  
Aerobic Plate Count

The chemical characteristics and microbiological examination of vacuum packaged ground buffalo meat during cold storage for 24 days were determined in order to evaluate two different antimicrobial agents sodium lactate, sodium chloride and their mixture. The results indicated that the use of sodium lactate with or without sodium chloride delayed the proliferation of aerobic plate count, psychotropic count, and lactic acid bacterial count, and extended the shelf life up to more than 24 and 21 days respectively, compared to 8 days for the control samples. The TBA values for the samples treated by sodium chloride was not affected, while at the end of storage period the TBA values of samples treated by sodium lactate were significantly reduce the oxidation changes. Therefore, the use of sodium lactate with or without sodium chloride could be used to extend the shelf life of ground buffalo meat during refrigerated storage by reducing both chemical and microbiological changes. .

Biodegradable Chitosan Coating Incorporated with Black Pepper Essential Oil for Shelf Life Extension of Common Carp (Cyprinus carpio) during Refrigerated Storage

2016 ◽  
Vol 79 (6) ◽  
pp. 986-993 ◽  
Author(s):  
MARZIEH MOOSAVI-NASAB ◽  
EHSAN SHAD ◽  
ESMAEIL ZIAEE ◽  
SEYYED HOSSEIN ASADI YOUSEFABAD ◽  
MOHAMMAD TAGHI GOLMAKANI ◽  
...  
Keyword(s):  
Shelf Life ◽  
Common Carp ◽  
Black Pepper ◽  
Plate Count ◽  
Refrigerated Storage ◽  
Psychrophilic Bacteria ◽  
Fish Fillet ◽  
Common Carp Cyprinus Carpio ◽  
Basic Nitrogen ◽  
Aerobic Plate Count

ABSTRACT Chitosan (Ch) coating incorporated with black pepper essential oil (Ch+BPEO) was studied to extend the shelf life of common carp (Cyprinus carpio) during refrigerated storage at 4 ± 1°C. The chemical composition of BPEO was characterized using gas chromatography–mass spectrometry (GC-MS). Antibacterial properties of BPEO were determined by disk diffusion agar, MIC, and MBC. Ch (2% [wt/vol]) and Ch+BPEO (2% [wt/vol] Ch with 1.5% [vol/vol] BPEO) were used for common carp fillet coating. The samples were analyzed periodically for chemical (pH, total volatile basic nitrogen) and microbiological (aerobic plate count, psychrophilic bacteria count, lactic acid bacteria, and Enterobacteriaceae bacterial counts) characteristics during 16 days. The GC-MS results indicated that main components in BPEO were carene, caryophyllene, limonene, β-pinene, and α-pinene. The samples coated with Ch and Ch+BPEO resulted in lower pH and total volatile basic nitrogen values in comparison with the control. The microbiological analysis of fish fillets during refrigerated storage clearly indicated that Ch+BPEO coating significantly reduced the fish fillet microbial load. The aerobic plate count, psychrophilic bacteria count, lactic acid bacteria count, and Enterobacteriaceae bacterial count of samples coated with Ch+BPEO were reduced approximately 4.1, 3.9, 2.3, and 2.8 log CFU/g, respectively, at the end of the storage period. Finally, Ch and Ch+BPEO effectively improved the quality of fish fillet during refrigerated storage and extended the shelf life of fish fillets from 8 to 16 days.

Relationships of Microbial Quality of Retail Meat Samples and Sanitary Conditions1

1980 ◽  
Vol 43 (5) ◽  
pp. 385-389 ◽  
Author(s):  
C. JANE WYATT ◽  
V. GUY
Keyword(s):  
Bacterial Load ◽  
Microbiological Quality ◽  
Plate Count ◽  
Microbiological Analysis ◽  
Food Stores ◽  
Aerobic Plate Count ◽  
Quality Of Products ◽  
Meat Samples ◽  
Sanitary Conditions

A sanitation profile scoring form for evaluating sanitation in retail food stores was designed. The profile was tested in 10 Oregon retail markets to evaluate its ability to reflect sanitary conditions. At the time of inspection, samples of meat processed in-store were purchased for microbiological analysis to explore the feasibility of bacterial quality as a measurement of sanitary conditions. Microbiological tests performed included total aerobic plate count (A PC), coliform, Escherichia coli, Staphylococcus aureus, Clostridium perfringens, and Salmonella. Certain deficiencies were noted in the profile designed; however, it provides a means for objective, uniform measurement of sanitary conditions. Data show no correlation exists between microbiological quality of products processed in the store and total store profile sanitary conditions. Fifty percent of the products sampled exceeded bacterial load guidelines currently enforced in Oregon. These “high” counts appear to be directly related to poor temperature control.

Influence of Processing on Bacteriological Quality of Frozen Shrimp

1983 ◽  
Vol 46 (7) ◽  
pp. 572-577 ◽  
Author(s):  
RABIA ZUBERI ◽  
R. B. QADRI ◽  
PIRZADA M. A. SIDDIQUI
Keyword(s):  
Fecal Coliform ◽  
Fecal Coliforms ◽  
Plate Count ◽  
Total Plate Count ◽  
Processing Plants ◽  
Commercial Processing ◽  
Aerobic Plate Count ◽  
Frozen Shrimp ◽  
Sanitary Conditions

Line and finished product samples (668) from two shrimp processing plants located at the Karachi fish harbor were collected and examined bacteriologically. Frozen shrimp samples (100) collected from Plant A had the following bacterial profile: average (geometric) total aerobic plate count 9.4 × 106 CFU/g; MPN coliforms 94/g; and MPN fecal coliforms 41/g. The bacterial profile of 114 frozen shrimp samples from Plant B were 8.3 × 106 CFU/g, 180/g and 133/g for total plate count, MPN coliform and MPN fecal coliforms, respectively. Samples (126) of raw and laboratory-processed (simulating commercial processing) shrimp were also examined. Processing conditions of Plant A were better and resulted in a better quality end-product as compared to that of Plant B. Three of 338 samples from Plant B yielded Salmonella. The composition of microbial flora was nearly the same for both species of shrimps from both plants. Pseudomonads were the predominant microflora followed by Micrococcus sp. When shrimp were handled expeditiously under good sanitary conditions in the laboratory, the bacterial counts were significantly lower than on shrimp from the plants. Laboratory-processed shrimp had an average (geometric) total aerobic plate count of 8.1 × 105 CFU/g and average (geometric) coliform and fecal coliform MPNs were <3/g.

Molecular Analysis of Spoilage-Related Bacteria in Pasteurized Milk during Refrigeration by PCR and Denaturing Gradient Gel Electrophoresis

2009 ◽  
Vol 72 (3) ◽  
pp. 572-577 ◽  
Author(s):  
HONGFEI HE ◽  
JIN DONG ◽  
CHIN NYEAN LEE ◽  
YONG LI
Keyword(s):  
Shelf Life ◽  
Gel Electrophoresis ◽  
Denaturing Gradient Gel Electrophoresis ◽  
Plate Count ◽  
Pasteurized Milk ◽  
Milk Samples ◽  
Gradient Gel Electrophoresis ◽  
Aerobic Plate Count ◽  
Species Specific

Bacterial diversity in fluid milk products has been extensively studied in order to improve milk quality. Here, we illustrate the utility of viable counts and PCR–denaturing gradient gel electrophoresis (DGGE) for monitoring the microbial spoilage of pasteurized milk during shelf life. Five pasteurized milk samples stored at 4°C were examined at 10 and 5 days before expiration and on the expiration day. With bacterial DNA extracted directly from the samples, PCR-DGGE analysis indicated that Pseudomonas became dominant in four samples. Meanwhile, the aerobic plate count of these four samples exceeded the regulatory limit of 20,000 CFU/ml at 5 days before expiration, and the rapid psychrotrophic count markedly surpassed the aerobic plate count on the expiration day. Streptococcus and Buttiauxella spp. were detected in several samples. Sequence analysis of DGGE fragments revealed high diversity among Pseudomonas spp. in the milk samples. P. putida and P. migulae grew to high numbers during refrigerated storage. Further identification of Pseudomonas at the species level was facilitated by PCR and multiplex PCR using species-specific primers; consequently, P. fluorescens and P. fragi were observed. These results highlight an important role of Pseudomonas in the shelf life of pasteurized milk.

scholarly journals Microbiological, chemical, and sensory assessment of Pacific oysters (Crassostrea gigas) stored at different temperatures

2009 ◽  
Vol 27 (No. 2) ◽  
pp. 102-108 ◽  
Author(s):  
R. Cao ◽  
Ch.-H. Xue ◽  
Q. Liu ◽  
Y. Xue
Keyword(s):  
Shelf Life ◽  
Storage Temperature ◽  
Plate Count ◽  
Lag Phase ◽  
Sensory Assessment ◽  
Pacific Oysters ◽  
Basic Nitrogen ◽  
Different Temperatures ◽  
Aerobic Plate Count ◽  
Dominant Bacteria

The changes were studied in microbiological, chemical, and sensory properties of Pacific oysters stored at 10°C, 5°C, and 0°C. <I>Pseudomonas</I> (22%) and <I>Vibrionaceae</I> (20%) species were dominant in raw oysters. The dominant bacteria found in the spoiled samples were <I>Pseudomonas</I> regardless of the storage temperature. During storage, rapid increases in aerobic plate count (APC) values of the samples stored at 10°C and 5°C were observed, while no obvious lag phases were detected. With the samples stored at 0°C, a decrease in APC value during the first 4 days and a lag phase of about 6 days were observed. The APC values of the samples stored at 10°C, 5°C, and 0°C reached the level of 10<sup>7</sup> CFU/g on day 6, 10, and 18, respectively. All the tested samples stored at different temperatures revealed a slight decrease in pH and a significant increase of total volatile basic nitrogen (TVB-N) during storage. The average TVB-N concentration of about 22.0 mg N/100 g was observed at the end of the shelf-life as determined by APC. Combined with the sensory assessments, the shelf-life of 6–7, 10–11, and 17–18 days for oysters stored at 10°C, 5°C, and 0°C, respectively, was determined.

scholarly journals Perubahan Fisiko-Kimiawi dan Mikrobiologis Minuman Tradisional Bali (Loloh) selama Penyimpanan

2019 ◽  
Vol 39 (1) ◽  
pp. 70
Author(s):  
I Desak Putu Kartika Pratiwi ◽  
I Ketut Suter ◽  
Putu Ari Sandhi Widpradnyadewi ◽  
Anak Agung Istri Sri Wiadnyani
Keyword(s):  
Vitamin C ◽  
Shelf Life ◽  
Room Temperature ◽  
Titratable Acidity ◽  
Plate Count ◽  
Total Plate Count ◽  
Microbiological Characteristics ◽  
Physico Chemical ◽  
Soluble Solid ◽  
Standard Limit

Loloh is a Balinese traditional beverage made from one or a combination of several herbal extracts. The most popular variants of loloh in Bali are loloh tibah and loloh cem-cem, which are continuously produced every day. During distribution, loloh is stored at room temperature. The study was aimed to study the physico-chemical and microbiological characteristics of loloh cem-cem and loloh tibah during storage at room temperature.  This study used a purposive random sampling. The samples consisted of 14 loloh sellers in Badung-Denpasar. Type parameters that were observed during a 24 hour-storage at room temperature included pH, total soluble solid, titratable acidity, ascorbic acid, total plate count, total yeast and mold count. During room temperature storage, the level of total plate count, total mold/yeast of loloh cem-cem and loloh tibah changed significantly. The shelf life of loloh cem-cem was only 12 hours at room temperature (28-30 oC) with the characteristics of pH 2.95, TSS 5.67 °Brix, vitamin C 19.35 mg/100 g, titratable acidity 0.24%, log total plate count 6.48 Cfu/mL, log total mold/yeast 5.01 Cfu/mL. The shelf life of Loloh tibah was only 12 hours at room temperature (28-30 ºC) with the characteristics of pH 3.34, TSS 4.21 °Brix, Vitamin C 10.20 mg/100 g, titratable acidity 0.13%, log total plate count 6.68 Cfu/mL, log total mold/yeast 5.86 Cfu/mL. Beyond the 12 hour-storage, both of the lolohs had higher total colony counts than the upper standard limit.

Inhibition of Nonproteolytic, Psychrotrophic Clostridia and Anaerobic Sporeformers by Sodium Diacetate and Sodium Lactate in Cook-in-Bag Turkey Breast†,‡

2003 ◽  
Vol 66 (8) ◽  
pp. 1474-1478 ◽  
Author(s):  
J. D. MEYER ◽  
J. G. CERVENY ◽  
J. B. LUCHANSKY
Keyword(s):  
Shelf Life ◽  
Antimicrobial Agents ◽  
Sodium Lactate ◽  
Refrigerated Storage ◽  
Internal Temperature ◽  
Food Grade ◽  
Plate Counts ◽  
Sodium Diacetate ◽  
Pink Discoloration

A nonproteolytic, psychrotrophic Clostridium isolate, designated strain OMFRI1, was recovered from cook-in-bag turkey breasts (CIBTB) that displayed an intense pink discoloration and an off-odor following extended refrigerated storage. The viability of strain OMFRI1 in CIBTB containing sodium diacetate (at 0, 0.25, and 0.5%) and/or sodium lactate (at 0, 1.25, and 2.5%) was subsequently evaluated. Raw CIBTB batter was inoculated with 9 to 30 spores of strain OMFRI1 per g, vacuum packaged, cooked to an instantaneous internal temperature of 71.1°C, chilled, and incubated at 4°C for up to 22 weeks. In the absence of food-grade antimicrobial agents, spoilage (i.e., an off-odor) occurred within 6 weeks, and anaerobic plate counts reached 6.6 log10 CFU/g. The CIBTB containing sodium diacetate (0.25%) and that containing sodium lactate (1.25%) required 12 weeks for spoilage to occur and for anaerobic plate counts to reach 7.0 and 6.0 log10 CFU/g, respectively. When sodium diacetate (0.25%) and sodium lactate (1.25%) were used in combination, no off-odor was detected and anaerobic plate counts did not exceed 2.3 log10 CFU/g over 22 weeks of storage at 4°C. In related experiments, sodium diacetate (at 0, 0.25, and 0.5%), sodium lactate (at 0, 1.25, and 2.5%), and combinations of both ingredients were evaluated in uninoculated CIBTB incubated at 25°C for up to 22 days. In the absence of antimicrobial agents and in CIBTB containing sodium diacetate (0.5%), spoilage occurred within 8 days and anaerobic plate counts reached 6.8 and 6.6 log10 CFU/g, respectively. Samples of CIBTB containing sodium lactate (2.5%) showed signs of spoilage within 22 days, and anaerobic plate counts for these samples ranged from ≤1.0 to 6.3 log10 CFU/g. In CIBTB containing both sodium lactate (2.5%) and sodium diacetate (0.25%), spoilage was not evident and anaerobic plate counts were ≤1.0 log10 CFU/g within 22 days. These data validate the efficacy of sodium lactate and sodium diacetate in extending the shelf life of CIBTB.

scholarly journals Effect of Chitosan/Nano-Titanium Dioxide/Thymol and Tween Films on Ready-to-Eat Cantaloupe Fruit Quality

Coatings ◽  
2019 ◽  
Vol 9 (12) ◽  
pp. 828 ◽  
Author(s):  
Guohua Qiao ◽  
Zhigang Xiao ◽  
Wenxin Ding ◽  
Ahmed Rok
Keyword(s):  
Ascorbic Acid ◽  
Titanium Dioxide ◽  
Shelf Life ◽  
Fruit Quality ◽  
Antimicrobial Agents ◽  
Control Sample ◽  
Soluble Solids ◽  
Mold And Yeast ◽  
Nano Titanium Dioxide ◽  
Population Counts

The effect of chitosan/nano-titanium dioxide coating with antimicrobial agents on ready to eat cantaloupe fruit by chilling was investigated. In comparison with uncoated samples, ascorbic acid and juice leakage in chitosan/nano-titanium dioxide (CH/TiO2) treated fruit were significantly maintained. Likewise, the decrease of malondialdehyde (MDA) and total soluble solids (TSS) in chitosan/nano-titanium dioxide/thymol/tween (CH/TiO2/TT) coated fruits was also inhibited. Total mold and yeast population counts decreased from 2.60 to 1.60 log CFU/g, respectively. Moreover, activities of water (AW) and polyphenol oxidase (PPO) were also much lower than those in control sample fruit. The results indicated that (CH/TiO2/TT) coating was effective in enhancing the shelf life with acceptable in the internal and the external cantaloupe fruit quality.

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