Microbial Flora of Normal and High pH Beef Stored at 4 C in Different Gas Environments

1981 ◽  
Vol 44 (11) ◽  
pp. 866-869 ◽  
Author(s):  
INGER ERICHSEN ◽  
GÖRAN MOLIN
Keyword(s):  
Lactic Acid ◽  
Lactic Acid Bacteria ◽  
Shelf Life ◽  
Microbial Flora ◽  
Gas Mixture ◽  
High Ph ◽  
Pseudomonas Spp ◽  
Brochothrix Thermosphacta

Beef of high pH (6.6) and of normal pH (5.8) was packed in air, a mixture of 78% N2 + 20% CO2 + 2% 02, vacuum, and 100% CO2 and stored at 4 C. The effect of the different gas environments on development of the microbial flora of the two types of beef was examined. The shelf-life increased in the order: pure CO2 > vacuum > gas mixture (20% CO2 > air. After storage in air for 14 days, Pseudomonas spp. comprised 76% of the flora on the normal beef and 88% of the flora on the high pH beef. In the gas mixture, after 21 days the microbial flora on the normal beef was dominated by lactic acid bacteria (52%), Enterobacteriaceae (16 %) and coryneforms (16 %) while the high pH beef contained Pseudomonas spp. (44 %), lactic acid bacteria (28%) and Brochothrix thermosphacta (28%). In the vacuum, after 21 days 96% of the flora in normal beef consisted of lactic acid bacteria, whereas 60% lactic acid bacteria and 40% B. thermosphacta were found on the high pH beef. In pure CO2, stored for 51 days, both the normal and high pH beef were completely dominated by lactic acid bacteria.

Microbiology of Pork Packaged in Various Gas Atmospheres

1979 ◽  
Vol 42 (4) ◽  
pp. 323-327 ◽  
Author(s):  
F. M. CHRISTOPHER ◽  
C. VANDERZANT ◽  
Z. L. CARPENTER ◽  
G. C. SMITH
Keyword(s):  
Lactic Acid ◽  
Lactic Acid Bacteria ◽  
Gas Mixtures ◽  
Microbial Flora ◽  
Significant Part ◽  
Pseudomonas Spp ◽  
C 50 ◽  
D 20 ◽  
Retail Conditions ◽  
Lactobacillus Spp

Boneless pork roasts were vacuum-packaged; one group remained in vacuum-packages (controls), other vacuum-packages were injected with one of six gas mixtures: (a) 100% O2, (b) 20% CO2 + 80% N2, (c) 50% CO2 + 50% O2. (d) 20% CO2 + 80% O2, (e) 25% CO2 + 25% O2 + 50% N2, or (f) 51% CO2 + 30% O2 + 18% N2 + 1% CO. Roasts were stored from 0–35 days at 1–3 C and chops from each treatment were observed under retail conditions for 5 days. Differences, both in psychrotrophic and lactobacillus counts, between roasts stored in modified gas atmospheres and those stored in vacuum-packages were rarely statistically significant. Psychrotrophic counts of pork chops from roasts stored for 21–35 days in modified gas atmospheres were somewhat higher than those prepared from comparable vacuum-packaged roasts. However, few of these differences were statistically significant. The initial microbial flora of the roasts consisted of Pseudomonas and Lactobacillus spp. Pseudomonas spp. remained a significant part of the microflora of roasts stored in 100% O2, whereas lactic acid bacteria (Lactobacillus and Leuconostoc spp.) predominated on roasts after 1 week in all other atmospheres.

Methods of Chilling and Packaging of Beef, Pork and Lamb Variety Meats for Transoceanic Shipment: Microbiological Characteristics

1985 ◽  
Vol 48 (9) ◽  
pp. 765-769 ◽  
Author(s):  
C. VANDERZANT ◽  
M. O. HANNA ◽  
J. G. EHLERS ◽  
J. W. SAVELL ◽  
D. B. GRIFFIN ◽  
...  
Keyword(s):  
Lactic Acid ◽  
Lactic Acid Bacteria ◽  
Refrigerated Storage ◽  
Coryneform Bacteria ◽  
Pseudomonas Spp ◽  
Microbiological Characteristics ◽  
Brochothrix Thermosphacta ◽  
Plate Counts ◽  
Ice Water

The effect of various initial chilling treatments on the numbers and types of microorganisms of beef, pork and lamb tongues (n = 60) and livers (n = 60) packaged either in polyethylene (PE) film or in vacuum packages in Texas and transported fresh-chilled via transoceanic shipment to Antwerp, Belgium, was evaluated. Initial chilling treatments included: cooler-tempered (4 to 6 h at 2°C), cooler-chilled (24 h at 2°C) freezer-tempered (0.5 to 1 h at −20°C), freezer-chilled (2 h at −20°C), ice-chilled (2 h in ice water slush) and no prechilling (NPC) before packaging and subsequent refrigerated storage at 2°C. After the initial chilling treatments, the microflora was varied with Micrococcus spp. with or without coryneform bacteria being the predominant bacterial types of most samples. After refrigerated storage for 13 to 15 d, lactic acid bacteria became dominant in most vacuum-packaged samples and in pork and lamb samples stored in PE film. Brochothrix thermosphacta and Pseudomonas spp. constituted a greater part of the microflora of beef tongues and livers stored in PE film than that of comparable vacuum-packaged samples. Increases in aerobic plate counts (APC) of refrigerated vacuum-packaged samples nearly always were greatest for samples (NPC) that were not pre-chilled before packaging and usually were smallest for samples that were either freezer-chilled, freezer-tempered or ice-chilled.

Effect of Aerobic Storage before Vacuum Packaging on the pH, Color and Bacterial Flora of Beef1

1983 ◽  
Vol 46 (4) ◽  
pp. 287-291 ◽  
Author(s):  
E. A. FOEGEDING ◽  
H. D. NAUMANN ◽  
W. C. STRINGER
Keyword(s):  
Lactic Acid ◽  
Lactic Acid Bacteria ◽  
Storage Time ◽  
Bacterial Flora ◽  
Color Difference ◽  
Major Effect ◽  
Vacuum Packaging ◽  
Pseudomonas Spp ◽  
Brochothrix Thermosphacta ◽  
Plate Counts

Beef was stored aerobically for 2 or 6 d at 1 ± 1°C before vacuum packaging. Total numbers of aerobic bacteria, Pseudomonas spp., Brochothrix thermosphacta and lactic acid bacteria were determined by selectively plating stored samples. Meat color was evaluated with a color difference meter and a color panel. Aerobic plate counts, numbers of pseudomonads and B. thermosphacta, and pH each were higher in samples held aerobically for 6 d compared with those held aerobically for 2 d. The major effect of delayed vacuum packaging was to slow the growth of lactic acid bacteria and minimize the number of pseudomonads. The variation among treatments was similar in Pseudomonas spp. population for 21 d and in pH for 7 d, and there was no significant effect of packaging treatment in color. Results indicate that the initial treatment variations were lost as storage time progressed.

scholarly journals Microbiological Condition of Retail Beef Steaks: A Canadian Survey

2018 ◽  
Vol 7 (4) ◽  
pp. 1 ◽  
Author(s):  
Xianqin Yang ◽  
Julia Devos ◽  
Hui Wang ◽  
Mark Klassen
Keyword(s):  
Escherichia Coli ◽  
Lactic Acid ◽  
Lactic Acid Bacteria ◽  
Microbial Quality ◽  
Indicator Organisms ◽  
Mean Values ◽  
E Coli ◽  
Upper Limit ◽  
Brochothrix Thermosphacta ◽  
Beef Steaks

The second national baseline microbiological survey of beef steaks offered for retail in Canada was conducted in 2015. A total of 621 steaks of four types (cross rib, CR; inside round, IR; striploin, SL; top sirloin, TS) collected from 135 retail stores in five cities across Canada were tested. Swab samples each from swabbing the entire upper surface of each steak were processed for enumeration of seven groups of indicator organisms: total aerobes (AER), psychrotrophs (PSY), lactic acid bacteria (LAB), pseudomonads (PSE), Brochothrix thermosphacta (BRO), coliforms (COL) and Escherichia coli (ECO). The overall mean values (log CFU/100 cm2) were 5.17±1.29, 4.92±1.36, 4.79±1.42, 3.26±1.49, 2.34±1.88, and 0.80±1.05 for AER, PSY, LAB, PSE, BRO, and COL, respectively. ECO were not recovered from 87.3% of the steaks and when there was recovery, the numbers were mostly ≤ 1 log CFU/100 cm2. Strong correlation was found between the log numbers of AER and PSY, of AER and LAB, and of PSY and LAB, while the correlation between the log numbers of COL and ECO was weak. The numbers of COL and ECO from different groups of steak types or from different cities were not substantially different. Of the four types of steaks, IR had the lowest median values for AER, PSY, LAB, PSE and BRO, followed by CR. The microbiological condition of retail beef steaks in this survey was on par with that in the previous one, with very low numbers of generic E. coli being recovered from very few steaks and the indicators for microbial quality being at numbers much lower than the upper limit for shelf life of beef.

Effect of Single or Sequential Hot Water and Lactic Acid Decontamination Treatments on the Survival and Growth of Listeria monocytogenes and Spoilage Microflora during Aerobic Storage of Fresh Beef at 4, 10, and 25°C

2004 ◽  
Vol 67 (12) ◽  
pp. 2703-2711 ◽  
Author(s):  
KONSTANTINOS P. KOUTSOUMANIS ◽  
LAURA V. ASHTON ◽  
IFIGENIA GEORNARAS ◽  
KEITH E. BELK ◽  
JOHN A. SCANGA ◽  
...  
Keyword(s):  
Lactic Acid ◽  
Listeria Monocytogenes ◽  
Lactic Acid Bacteria ◽  
Hot Water ◽  
Microbial Profile ◽  
Spoilage Bacteria ◽  
Brochothrix Thermosphacta ◽  
Survival And Growth ◽  
Spoilage Microflora ◽  
Storage Temperatures

The survival and growth of Listeria monocytogenes and spoilage microflora during storage of fresh beef subjected to different decontamination treatments was studied. Fresh beef inoculated with a five-strain mixture of L. monocytogenes (5.18 log CFU/cm2) was left untreated (control) or was immersed (30 s) in hot water (HW; 75°C), 2% lactic acid (LA; 55°C), hot water followed by lactic acid (HW-LA), or lactic acid followed by hot water (LA-HW) and then stored aerobically at 4, 10, and 25°C for 25, 17, and 5 days, respectively. Initial populations of L. monocytogenes were reduced by 0.82 (HW), 1.43 (LA), 2.73 (HW-LA), and 2.68 (LA-HW) log CFU/cm2. During storage, the pathogen grew at higher rates in HW than in control samples at all storage temperatures. Acid decontamination treatments (LA, HW-LA, and LA-HW) resulted in a weaker inhibition of L. monocytogenes (P < 0.05) at 25°C than at 4 and 10°C. In general, the order of effectiveness of treatments was HW-LA > LA > LA-HW > HW > control at all storage temperatures tested. In untreated samples, the spoilage microflora was dominated by pseudomonads, while lactic acid bacteria, Enterobacteriaceae, and yeasts remained at lower concentrations during storage. Brochothrix thermosphacta was detected periodically in only a limited number of samples. Although decontamination with HW did not affect the above spoilage microbial profile, acid treatments shifted the predominant microflora in the direction of yeasts and gram-positive bacteria (lactic acid bacteria). Overall, the results of the present study indicate that decontamination with LA and combinations of LA and HW could limit growth of L. monocytogenes and inhibit pseudomonads, which are the main spoilage bacteria of fresh beef stored under aerobic conditions. However, to optimize the efficacy of such treatments, they must be applied in the appropriate sequence and followed by effective temperature control.

Cassava starch/carboxymethylcellulose edible films embedded with lactic acid bacteria to extend the shelf life of banana

2020 ◽  
Vol 248 ◽  
pp. 116805 ◽  
Author(s):  
Siying Li ◽  
Yanlan Ma ◽  
Tengteng Ji ◽  
Dur E. Sameen ◽  
Saeed Ahmed ◽  
...  
Keyword(s):  
Lactic Acid ◽  
Lactic Acid Bacteria ◽  
Shelf Life ◽  
Edible Films ◽  
Cassava Starch
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