scholarly journals Effects of moisture and temperature on Salmonella survivability in beef tallow, white grease and chicken rendered fat

2021 ◽  
Author(s):  
A Molitor ◽  
U Yucel ◽  
J Vipham ◽  
C Jones ◽  
V Trinetta
Keyword(s):  
Beef Tallow ◽  
Weibull Model ◽  
Inoculum Level ◽  
Progressive Decline ◽  
Growth And Survival ◽  
White Grease ◽  
Challenge Study ◽  
Poultry Fat ◽  
Rendered Fat ◽  
And Storage

Abstract High moisture levels introduced to fats after the rendering process can lead to Salmonella presence and growth. Limited research on strategies to eliminate pathogens in these environments are available. Rendered fat characteristics, such as water activity and fatty acids composition, may contribute to Salmonella survivability. The purpose of this research was to evaluate the effects of moisture levels (0%, 0.5%, 1%, and 3%), storage temperatures (48˚C and 76˚C), and fat characteristics on the growth and survival of Salmonella in beef tallow, white grease and poultry fat samples. Samples were inoculated with a high (~10⁸ CFU/mL) and a low (~10⁵ CFU/mL) Salmonella cocktail (S. Sentfenberg, S. Newport, S. Thompson and S. Infantis). Samples were stored for up to 5 days at 48 and 76 ºC. Remaining population was evaluated daily with and without enrichment step. Death rates were calculated using Weibull model for each temperature and moisture level. Only temperature had an effect (P < 0.05) on Salmonella inactivation, while no effect between moisture and/or inoculum level were observed. When all products were challenged at 76 ˚C, counts were below detectable limits after 6 hours. At 48˚C a progressive decline in Salmonella population was observed within 3 days for both beef tallow and white grease when high inoculum was used for the challenge study. Salmonella was below detectable limit within 4 days for both fat types when a low inoculum was instead applied. This research identified the effect of moisture and temperature in rendered fat samples contaminated with Salmonella and underlined the need to use time-moisture-temperature data to minimize microbial growth during transportation and storage.

scholarly journals Effects of different moisture and temperature levels on Salmonella survival in poultry fat

2019 ◽  
Vol 3 (4) ◽  
pp. 1369-1374
Author(s):  
Valentina Trinetta ◽  
Austin McDaniel ◽  
Gabriela Magossi ◽  
Umut Yucel ◽  
Cassandra Jones
Keyword(s):  
Salmonella Spp ◽  
Inoculum Level ◽  
Residual Moisture ◽  
Growth And Survival ◽  
Poultry Fat ◽  
Low Levels ◽  
Temperature Levels ◽  
And Storage ◽  
Salmonella Survival ◽  
Storage Temperatures

Abstract Fat products have been historically thought to have too low water activity to harbor pathogens. However, it has been recently reported that high moisture levels in fats may lead to Salmonella presence and growth. Limited research on strategies to eliminate pathogens in these environments is available, and the mechanisms contributing to microbial presence and growth are not yet well understood. The purpose of this research was to evaluate the effects of moisture levels and storage temperatures on the growth and survival of Salmonella in poultry fat. Samples were stored for 7 d at 48°C or 76°C and remaining Salmonella was evaluated. When poultry fat was challenged with a wet high inoculum, more than a 4 log CFU/mL difference in Salmonella population was observed with 1% and 3% moisture levels at 48°C after 5 d (P < 0.05). No differences between moisture levels (P > 0.05) were observed when samples were tested with a wet low inoculum. Counts below detectable limits were observed after 24 h in samples challenged at 76°C, regardless of inoculum level. When poultry fat was stored at 48°C and inoculated with low levels of Salmonella spp., bacterial growth was influenced only by time (P < 0.05) and not affected (P > 0.05) by moisture level. However, when poultry fat was stored at 48°C and inoculated with high levels of Salmonella spp., bacterial decrease was easier (P < 0.05) in samples containing greater moisture. This research suggests that residual moisture in containers during transportation of poultry fat largely does not affect Salmonella spp. growth.

scholarly journals Influence of Different Filling, Cooling, and Storage Conditions on the Growth of Alicyclobacillus acidoterrestris CRA7152 in Orange Juice

2009 ◽  
Vol 75 (23) ◽  
pp. 7409-7416 ◽  
Author(s):  
Ana Cláudia N. F. Spinelli ◽  
Anderson S. Sant'Ana ◽  
Salatir Rodrigues-Junior ◽  
Pilar R. Massaguer
Keyword(s):  
Orange Juice ◽  
Storage Temperature ◽  
Growth Parameters ◽  
Storage Conditions ◽  
Inoculum Level ◽  
Alicyclobacillus Acidoterrestris ◽  
Time Required ◽  
Cold Point ◽  
And Storage ◽  
A Current

ABSTRACT The prevention of spoilage by Alicyclobacillus acidoterrestris is a current challenge for fruit juice and beverage industries worldwide due to the bacterium's acidothermophilic growth capability, heat resistance, and spoilage potential. This study examined the effect of storage temperature on A. acidoterrestris growth in hot-filled orange juice. The evolution of the A. acidoterrestris population was monitored under six different storage conditions after pasteurization (at 92°C for 10 s), maintenance at 85°C for 150 s, and cooling with water spray to 35°C in about 30 min and using two inoculum levels: <101 and 101 spores/ml. Final cooling and storage conditions were as follows: treatment 1, 30°C for the bottle cold point and storage at 35°C; treatment 2, 30°C for 48 h and storage at 35°C; treatment 3, 25°C for the bottle cold point and storage at 35°C; treatment 4, 25°C for 48 h and storage at 35°C; treatment 5, storage at 20°C (control); and treatment 6, filling and storage at 25°C. It was found that only in treatment 5 did the population remain inhibited during the 6 months of orange juice shelf life. By examining treatments 1 to 4, it was observed that A. acidoterrestris predicted growth parameters were significantly influenced (P < 0.05) either by inoculum level or cooling and storage conditions. The time required to reach a 104 CFU/ml population of A. acidoterrestris was considered to be an adequate parameter to indicate orange juice spoilage by A. acidoterrestris. Therefore, hot-filled orange juice should be stored at or below 20°C to avoid spoilage by this microorganism. This procedure can be considered a safe and inexpensive alternative to other treatments proposed earlier.

scholarly journals Metabolic Responses of Lactobacillus plantarum Strains during Fermentation and Storage of Vegetable and Fruit Juices

2014 ◽  
Vol 80 (7) ◽  
pp. 2206-2215 ◽  
Author(s):  
P. Filannino ◽  
G. Cardinali ◽  
C. G. Rizzello ◽  
S. Buchin ◽  
M. De Angelis ◽  
...  
Keyword(s):  
Amino Acids ◽  
Lactobacillus Plantarum ◽  
Malic Acid ◽  
Gamma Aminobutyric Acid ◽  
Content Type ◽  
Growth And Survival ◽  
The Matrix ◽  
Cell Densities ◽  
Almost All ◽  
And Storage

ABSTRACTStrains ofLactobacillus plantarumwere grown and stored in cherry (ChJ), pineapple (PJ), carrot (CJ), and tomato (TJ) juices to mimic the chemical composition of the respective matrices. Wheat flour hydrolysate (WFH), whey milk (W), and MRS broth were also used as representatives of other ecosystems. The growth rates and cell densities ofL. plantarumstrains during fermentation (24 h at 30°C) and storage (21 days at 4°C) differed only in part, being mainly influenced by the matrix. ChJ and PJ were the most stressful juices for growth and survival. Overall, the growth in juices was negatively correlated with the initial concentration of malic acid and carbohydrates. The consumption of malic acid was noticeable for all juices, but mainly during fermentation and storage of ChJ. Decreases of branched-chain amino acids (BCAA)—with the concomitant increase of their respective branched alcohols—and His and increases of Glu and gamma-aminobutyric acid (GABA) were the main traits of the catabolism of free amino acids (FAA), which were mainly evident under less acidic conditions (CJ and TJ). The increase of Tyr was found only during storage of ChJ. Some aldehydes (e.g., 3-methyl-butanal) were reduced to the corresponding alcohols (e.g., 3-methyl-1-butanol). After both fermentation and storage, acetic acid increased in all fermented juices, which implied the activation of the acetate kinase route. Diacetyl was the ketone found at the highest level, and butyric acid increased in almost all fermented juices. Data were processed through multidimensional statistical analyses. Except for CJ, the juices (mainly ChJ) seemed to induce specific metabolic traits, which differed in part among the strains. This study provided more in-depth knowledge on the metabolic mechanisms of growth and maintenance ofL. plantarumin vegetable and fruit habitats, which also provided helpful information to select the most suitable starters for fermentation of targeted matrices.

Expression of resistance in bean pods to an incompatible isolate of Pseudomonas syringae

1977 ◽  
Vol 55 (15) ◽  
pp. 2043-2052 ◽  
Author(s):  
D. M. Webster ◽  
L. Sequeira
Keyword(s):  
Pseudomonas Syringae ◽  
Bacterial Growth ◽  
Ethanolic Extract ◽  
Fresh Weight ◽  
Inoculum Level ◽  
Bacterial Populations ◽  
Progressive Decline ◽  
High Inoculum ◽  
Inhibitory Compounds ◽  
Extract Fraction

Isolates of Pseudomonas syringae from hairy vetch were either virulent (compatible) or avirulent (incompatible) to bean. When bean pods were injected at high inoculum levels (5 × 107 cells/ml), both compatible and incompatible isolates multiplied rapidly and caused water-soaking of injected tissues; populations of both isolates were similar at the end of log phase. Lesions caused by the incompatible isolate turned brown by 3 days after inoculation and did not expand; those caused by the compatible isolate remained water-soaked and expanded into the adjoining, noninoculated tissues. At low inoculum levels (5 × 104 cells/ml), the compatible isolate exhibited the same pattern of multiplication and lesion development as at the high inoculum level. The incompatible isolate, on the other hand, caused necrotic flecking within the injected area by 24 h, and these small lesions remained limited. Appearance of the necrotic flecks was correlated with a progressive decline in bacterial populations; after5 days, the population of incompatible bacteria was about a hundredfold lower than that of compatible ones. Populations of incompatible bacteria within and between the necrotic flecks declined rapidly, indicating the potential accumulation of inhibitors of bacterial growth as a result of an inducible resistance mechanism.The phytoalexin phaseollin reached 280 μg/g fresh weight by 3 days after inoculation of bean pods with incompatible bacteria. However, this compound was not involved in resistance. Neither compatible nor incompatible isolates of the bacterium were significantly inhibited when grown in a medium saturated with phaseollin. When other antibiotic substances in plant extracts were sought, substantial amounts of inhibitory compounds were detected only in the ethanolic extract (fraction soluble in ethyl acetate) of pods previously inoculated with an incompatible isolate of P. syringae. Only low levels of inhibition were obtained from identical extracts of uninfected pods or from pods inoculated with a compatible isolate of P. syringae. Bacterial growth was completely prevented in a bean infusion medium containing 1 g fresh weight equivalent of pod tissue challenged with the incompatible isolate. The active compound(s) was nonfluorescent, had a UV absorption maximum at 286 nm, and gave a positive reaction with reagents for phenolic compounds.

Biocontrol of Salmonella Typhimurium in Raw Salmon Fillets and Scallop Adductors by Using Bacteriophage SLMP1

2018 ◽  
Vol 81 (8) ◽  
pp. 1304-1312 ◽  
Author(s):  
DONGQIN XU ◽  
YANHUA JIANG ◽  
LIANZHU WANG ◽  
LIN YAO ◽  
FENGLING LI ◽  
...  
Keyword(s):  
Detection Limit ◽  
Salmonella Typhimurium ◽  
Storage Time ◽  
Biocontrol Agent ◽  
Storage Temperature ◽  
Inoculum Level ◽  
Potential Effectiveness ◽  
Low Level ◽  
And Storage ◽  
Variation Trends

ABSTRACT The aim of this study was to evaluate the effectiveness of bacteriophage (phage) SLMP1 to reduce Salmonella Typhimurium on contaminated raw salmon fillets and scallop adductors as a function of Salmonella inoculum level, phage dose, storage temperature, and storage time. Samples were inoculated with 102 and 104 CFU/g Salmonella and then treated with different concentrations of phage SLMP1, followed by incubation at 4, 15, and 25°C, respectively. The results showed that 108 PFU/g was the optimal concentration of phage for the control of Salmonella, which was applied in the following storage experiments over a 7-day period at 4°C, a 4-day period at 15°C, and a 2-day period at 25°C. For the salmon fillets samples, 102 CFU/g Salmonella could be reduced below the detection limit at all three temperatures, whereas 104 CFU/g Salmonella was first decreased and then increased at 15 and 25°C. For the scallop adductors samples, 102 CFU/g Salmonella could be reduced below the detection limit first and then increased after a certain period at 15 and 25°C. The variation trends of 104 CFU/g Salmonella in scallop adductors were similar to those in salmon fillets. The results also showed that the Salmonella counts of both inoculum levels on samples could be reduced below the detection limit or maintained at a low level by phage SLMP1 during storage at 4°C. Phage SLMP1 remained stable on raw salmon fillets and scallop adductors. This study indicated that phage SLMP1 has potential effectiveness as a biocontrol agent of Salmonella in seafood.

Effects of Environment on Growth and Survival of Douglas-fir Transplants

1974 ◽  
Vol 4 (2) ◽  
pp. 193-200
Author(s):  
E. B. Tregunna ◽  
M. Crown
Keyword(s):  
Storage Time ◽  
Water Status ◽  
Douglas Fir ◽  
Planting Date ◽  
Growth And Survival ◽  
Lower Elevation ◽  
Survival And Growth ◽  
And Storage ◽  
Root Treatment ◽  
Spring Planting

Variation in lifting date, planting date, planting site, seedling history, root treatment, and storage time were tested for their effects on Douglas-fir transplants. Survival, water status, types of damage, and both shoot and root growth were measured. Survival decreased with later spring planting date in the field, but this was partly offset by trends in browsing. Survival was greater at the lower elevation. Differences in seed lot, or conditions in the nursery, resulted in differences in tree size, which had some effects because the larger trees were browsed more. Survival and growth were not markedly different between root treatments. Cold storage increased survival of trees lifted late in the spring. The relative turgidity of leaves from bareroot trees in storage was related to lifting date and subsequent survival. Survival decreased severely as lifting date progressed through March.

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