PREDOMINANT MICROORGANISMS ON RAW PLANT FOODS1,2

1970 ◽  
Vol 33 (11) ◽  
pp. 500-505 ◽  
Author(s):  
D. F. Splittstoesser
Keyword(s):  
Microbial Growth ◽  
Microbial Populations ◽  
Green Beans ◽  
Plant Foods ◽  
Microbial Counts ◽  
Equipment Contamination ◽  
Growth History

Considerable variation was observed in the microbial populations present on raw plant foods. Equipment contamination and microbial growth on the product following harvest often were responsible for high microbial counts. Because of these factors, vegetables protected by a pod or husk frequently were more heavily contaminated than those exposed to soil and air throughout their growth history. Similar types of microorganisms were isolated from raw and post-blanch samples of peas and green beans. The samples recontaminated after the blanch generally contained a higher proportion of catalase-negative cocci. Some of the properties of the more numerous groups are presented. Many of the isolates were sufficiently different from “type” cultures that they could not be readily placed into described species.

scholarly journals A Comparison of Sanitation Systems for Fresh-cut Mango

2005 ◽  
Vol 15 (4) ◽  
pp. 837-842 ◽  
Author(s):  
Jan Narciso ◽  
Anne Plotto
Keyword(s):  
Microbial Growth ◽  
Mangifera Indica ◽  
Quality Parameters ◽  
Microbial Populations ◽  
Sodium Chlorite ◽  
Peroxyacetic Acid ◽  
Microbial Counts ◽  
Fresh Cut ◽  
Microbial Stability ◽  
Sanitation Systems

A comparison of sanitizers for fresh-cut mango (Mangifera indica cv. Keitt) was made. Mangos were obtained from a farm in Homestead, Fla., and stored at 15 °C until processed. Before cutting, fruit were dipped in solutions of either sodium hypochlorite (NaOCl) (200 ppm) or peroxyacetic acid (100 ppm). The cut pieces were dipped in acidified sodium chlorite (NaClO2) (200 ppm, pH 2.6) or dilute peroxyacetic acid (50 ppm) for 30 seconds. Resulting cut slices were placed in polystyrene clamshell food containers and stored at 5 °C for 21 days. Samples in the clamshells were tested for changes in microbial stability and for quality parameters every 7 days. Results showed that even though the fruit slices were sanitized after cutting, cut fruit microbial populations were related to the method of whole fruit sanitation. After 15-21 days in storage at 5 °C, cut slices from whole fruit sanitized with peroxyacetic acid that were subsequently treated with dilute peroxyacetic acid or acidified NaClO2 had less contamination [<1 colony-forming unit (cfu) per gram] than samples cut from whole fruit sanitized with NaOCl (<1000 to 3700 cfu/g). These data demonstrate that the method of whole fruit sanitation plays a role in determining the cleanliness of the cut fruit. These sanitizer systems (peroxyacetic acid on whole fruit followed by peroxyacetic acid or acidified NaClO2 on cut slices) effectively reduced microbial growth and kept microbial counts low on cut fruit surfaces for 21 days when compared to cut fruit slices from NaOCl-treated whole fruit.

scholarly journals Enhancement in physicochemical parameters and microbial populations of mushrooms as influenced by nano-coating treatments

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Rokayya Sami ◽  
Abeer Elhakem ◽  
Amina Almushhin ◽  
Mona Alharbi ◽  
Manal Almatrafi ◽  
...  
Keyword(s):  
Physicochemical Parameters ◽  
Microbial Growth ◽  
Research Work ◽  
Microbial Populations ◽  
Coating Film ◽  
Epidermal Structure ◽  
Nano Coating ◽  
Soluble Solid ◽  
Button Mushrooms ◽  
White Button Mushrooms

AbstractWhite button mushrooms are greatly high perishable and can deteriorate within a few days after harvesting due to physicomechanical damage, respiration, microbial growth of the delicate epidermal structure. For that reason, the present research work was applied to evaluate the effect of chitosan combination with nano-coating treatments on physicochemical parameters and microbial populations on button mushrooms at chilling storage. Nano coating with the addition of nisin 1% (CHSSN/M) established the minimum value for weight loss 12.18%, maintained firmness 11.55 N, and color index profile. Moreover, O2% rate of (CHSSN/M) mushrooms was the lowest at 1.78%; while the highest rate was reported for CO2 24.88% compared to the untreated samples (Control/M) on day 12. Both pH and total soluble solid concentrations increased during storage. Results reported that the (CHSS/M) mushroom significantly (P < 0.05) reduced polyphenol oxidase activity (24.31 U mg−1 Protein) compared with (Control/M) mushrooms that increased faster than the treated samples. (CHSSN/M) treatment was the most efficient in the reduction of yeast and mold, aerobic plate microorganisms (5.27–5.10 log CFU/g), respectively. The results established that nano-coating film might delay the aging degree and accompany by marked prolongation of postharvest mushroom freshness.

scholarly journals Effects of Replacing Extruded Maize by Dried Citrus Pulp in a Mixed Diet on Ruminal Fermentation, Methane Production, and Microbial Populations in Rusitec Fermenters

Animals ◽  
2020 ◽  
Vol 10 (8) ◽  
pp. 1316
Author(s):  
Jairo García-Rodríguez ◽  
Cristina Saro ◽  
Iván Mateos ◽  
Jesús S. González ◽  
María Dolores Carro ◽  
...  
Keyword(s):  
Methane Production ◽  
Microbial Growth ◽  
Microbial Populations ◽  
Mixed Diet ◽  
Ruminal Fermentation ◽  
Citrus Industry ◽  
Ph Values ◽  
Citrus Pulp ◽  
Liquid Phases ◽  
Fermentation Parameters

Citrus pulp is a highly abundant by-product of the citrus industry. The aim of this study was to assess the effects of replacing extruded maize (EM; 20% of total diet) by dried citrus pulp (DCP; 20%) in a mixed diet on rumen fermentation and microbial populations in Rusitec fermenters. The two diets contained 50% alfalfa hay and 50% concentrate, and the same protein level. Four Rusitec fermenters were used in a cross-over design with two 13-d incubation runs. After 7-d of diet adaptation, diet disappearance, fermentation parameters, microbial growth, and microbial populations were assessed. Fermenters receiving the DCP showed greater pH values and fiber disappearance (p < 0.001) and lower methane production (p = 0.03) than those fed EM. Replacing EM by DCP caused an increase in the proportions of propionate and butyrate (p < 0.001) and a decrease in acetate (p = 0.04). Microbial growth, bacterial diversity, and the quantity of bacteria and protozoa DNA were not affected by the diet, but the relative abundances of fungi and archaea were greater (p < 0.03) in solid and liquid phases of DCP fermenters, respectively. Results indicate that DCP can substitute EM, promoting a more efficient ruminal fermentation.

Development of Microbial Populations in Fermented Wastes from Frozen Vegetable Processing

1981 ◽  
Vol 44 (4) ◽  
pp. 288-293 ◽  
Author(s):  
NANCY J. MOON
Keyword(s):  
Lactic Acid ◽  
Lactobacillus Plantarum ◽  
Microbial Populations ◽  
Soluble Carbohydrate ◽  
Population Changes ◽  
Green Beans ◽  
End Products ◽  
Facultative Anaerobic ◽  
Turnip Greens ◽  
Acetic Acids

Changes in microbial populations were evaluated in fermented silage-like products prepared from wastes generated during frozen vegetable processing. Lactobacillus plantarum (107/g) was used to inoculate wastes from black-eyed peas, corn, potatoes, turnip greens and green beans. Populations of facultative anaerobic flora (lactobacilli, lactic acid cocci), anaerobes (clostridia) and lactate-hydrolyzing microflora differed in silages of different composition. Development of microflora correlated with pH decline and production of volatile and nonvolatile acids. Lactic and acetic acids were produced early while secondary metabolic end products (propionic, butyric acids) accumulated later in silages as populations of clostridia and propionibacteria increased. Minimum pH levels were attained after 2 and 4 days of fermentation. Black-eyed pea and potato silages had relatively high pH levels (&gt;4.50). This was correlated with low soluble carbohydrate content. No generalized role could be determined for population changes of fungi or coliforms. The most desirable waste silages can be produced from temperature-stressed materials adjusted to proper composition to ensure optimum fermentation patterns.

Experiments in Sanitizing Beef With Sodium Hypochlorite1,2

1977 ◽  
Vol 40 (4) ◽  
pp. 246-249 ◽  
Author(s):  
R. T. MARSHALL ◽  
M. E. ANDERSON ◽  
H. D. NAUMANN ◽  
W. C. STRINGER
Keyword(s):  
Sodium Hypochlorite ◽  
Sampling Methods ◽  
Microbial Populations ◽  
Microbial Counts ◽  
Core Sampling ◽  
Single Passage ◽  
Line Pressure

Beef plate meat was sprayed with sodium hypochlorite (pH 6.0) from two sources, commercial and electroytically generated. Variables studied in two experiments were rate of flow of sanitizer, line pressure, speed of movement of meat through the sprays, and method and time of sanitization. Hypochlorite sprays reduced microbial counts significantly more than did water applied under the same conditions, but type of hypochlorite was unimportant. Maximum reductions in counts made immediately after sanitization approximated 97 and 93% as measured by swab and core sampling methods, respectively. Sprays were most effective when delivered in a single passage over meat at a rate of 2 rather than 10 cm/sec or in about seven successive passages at 10 cm/sec. Samples collected by coring and swabbing estimated microbial populations different from each other when the samples were taken after sanitized meat had been stored at 3 C for 48 h. Based on our findings we recommend the coring method.

scholarly journals Succession of microbial populations and nitrogen-fixation associated with the biodegradation of sediment-oil-agglomerates buried in a Florida sandy beach

2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Boryoung Shin ◽  
Ioana Bociu ◽  
Max Kolton ◽  
Markus Huettel ◽  
Joel E. Kostka
Keyword(s):  
Nitrogen Fixation ◽  
Petroleum Hydrocarbons ◽  
Microbial Growth ◽  
Sandy Beach ◽  
Sandy Beaches ◽  
Beach Sand ◽  
Microbial Populations ◽  
In Situ Experiment ◽  
Potential Threat ◽  
Nitrogenase Genes

AbstractThe Deepwater Horizon (DWH) oil spill contaminated coastlines from Louisiana to Florida, burying oil up to 70 cm depth in sandy beaches, posing a potential threat to environmental and human health. The dry and nutrient-poor beach sand presents a taxing environment for microbial growth, raising the question how the biodegradation of the buried oil would proceed. Here we report the results of an in-situ experiment that (i) characterized the dominant microbial communities contained in sediment oil agglomerates (SOAs) of DWH oil buried in a North Florida sandy beach, (ii) elucidated the long-term succession of the microbial populations that developed in the SOAs, and (iii) revealed the coupling of SOA degradation to nitrogen fixation. Orders of magnitude higher bacterial abundances in SOAs compared to surrounding sands distinguished SOAs as hotspots of microbial growth. Blooms of bacterial taxa with a demonstrated potential for hydrocarbon degradation (Gammaproteobacteria, Alphaproteobacteria, Actinobacteria) developed in the SOAs, initiating a succession of microbial populations that mirrored the evolution of the petroleum hydrocarbons. Growth of nitrogen-fixing prokaryotes or diazotrophs (Rhizobiales and Frankiales), reflected in increased abundances of nitrogenase genes (nifH), catalyzed biodegradation of the nitrogen-poor petroleum hydrocarbons, emphasizing nitrogen fixation as a central mechanism facilitating the recovery of sandy beaches after oil contamination.

MICROBIAL COUNTS OF INDIVIDUAL PRODUCER AND COMMINGLED GRADE A RAW MILK1

1973 ◽  
Vol 36 (3) ◽  
pp. 146-151 ◽  
Author(s):  
H. E. Randolph ◽  
B. K. Chakraborty ◽  
Otto Hampton ◽  
D. L. Bogart
Keyword(s):  
Statistical Significance ◽  
Correlation Coefficients ◽  
Raw Milk ◽  
Microbial Populations ◽  
Plate Count ◽  
Microbial Counts ◽  
Standard Plate Count ◽  
Standard Plate ◽  
Bulk Tank ◽  
Highly Correlated

Microbial populations of Grade A raw milk samples from 105 individual producers and 74 bulk tank trucks (commingled) were enumerated by Standard Plate Count (SPC), psychrotrophic count (PBC), coliform count (CC), laboratory pasteurized count (LPC), thermophilic count (TBC), yeast and mold count (Y&M), and special penicillin (PEN) and crystal violet tetrazolium (CVT) agar count procedures. In addition, microbial populations were determined by the SPC, PBC, PEN, and CVT procedures after preliminary incubation (PI) of samples. Initial mean counts obtained on individual producer samples were generally lower than those for commingled samples. However, producer samples had higher mean counts after PI. Growth ratios were lower for commingled than for individual producer samples indicating slower growth during PI. Results obtained by the PBC, PEN, and CVT procedures were similar when viewed as correlation coefficients, distribution of samples according to microbial counts, mean counts, and growth ratios during PI. Before PI, the correlation between these three tests was poor and lacked statistical significance when the PBC was &lt;50,000/ml. After PI, the tests were highly correlated (P&lt;0.01) and the r values ranged from 0.8 to 0.9 for samples with PBC levels above 108/ml.

scholarly journals Growth tradeoffs produce complex microbial communities on a single limiting resource

2018 ◽  
Author(s):  
Michael Manhart ◽  
Eugene I. Shakhnovich
Keyword(s):  
Microbial Growth ◽  
Growth Traits ◽  
Fundamental Problem ◽  
Higher Order ◽  
Microbial Populations ◽  
Order Effects ◽  
Pairwise Interactions ◽  
Lag Times ◽  
The Relationship ◽  
Higher Order Effects

The relationship between the dynamics of a community and its constituent pairwise interactions is a fundamental problem in ecology. Higher-order ecological effects beyond pairwise interactions may be key to complex ecosystems, but mechanisms to produce these effects remain poorly understood. Here we show that higher-order effects can arise from variation in multiple microbial growth traits, such as lag times and growth rates, on a single limiting resource with no other interactions. These effects produce a range of ecological phenomena: an unlimited number of strains can exhibit multi stability and neutral coexistence, potentially with a single keystone strain; strains that coexist in pairs do not coexist all together; and the champion of all pairwise competitions may not dominate in a mixed community. Since variation in multiple growth traits is ubiquitous in microbial populations due to pleiotropy and non-genetic variation, our results indicate these higher-order effects may also be widespread, especially in laboratory ecology and evolution experiments.

Quality Changes of Beef Steaks Stored in Controlled Gas Atmospheres Containing High or Low Levels of Oxygen1,2

1982 ◽  
Vol 45 (1) ◽  
pp. 41-45 ◽  
Author(s):  
LAURA BARTKOWSKI ◽  
F. D. DRYDEN ◽  
J. A. MARCHELLO
Keyword(s):  
Microbial Growth ◽  
Gas Mixtures ◽  
Microbial Counts ◽  
Red Color ◽  
Beef Steaks ◽  
Storage Atmosphere ◽  
Retail Display ◽  
Low Levels ◽  
Experimental Trials ◽  
Beef Color

Steaks from bovine Longissimus and Semimembranosus muscles were used to determine the influence of gas atmospheres on beef color, microbial growth and shrinkage during 9 days of retail display in two separate experimental trials. Steaks were displayed in one of four gas mixtures and were compared to steaks packaged under conventional vacuum and in a film wrap. Gas mixtures containing O2 levels of 10% (one-half ambient) did not maintain a bright red color, but those with 40–75% O2 (more than twice ambient) maintained acceptable color for 9 days of storage. Atmosphere stored steaks lost more moisture (P&lt;0.05) than vacuum-packaged steaks. Psychrotrophic and mesophilic microbial counts from steaks stored 9 days in atmospheres containing 15% CO2 were lower (P&lt;0.05) than the counts for the control steaks.

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