Survival and Growth of Staphylococcus aureus on Temperature-Abused Beef Livers

1984 ◽  
Vol 47 (4) ◽  
pp. 260-262 ◽  
Author(s):  
B. W. BERRY ◽  
K. F. LEDDY ◽  
C. A. ROTHENBERG
Keyword(s):  
Staphylococcus Aureus ◽  
Storage Temperature ◽  
Frozen Storage ◽  
Storage Period ◽  
Developed Countries ◽  
Slow Surface ◽  
Plate Counts ◽  
Survival And Growth ◽  
High Storage ◽  
Storage Temperatures

Beef livers from freshly slaughtered cattle were inoculated with coagulase-positive Staphylococcus aureus and then placed in frozen storage. After 14 d of frozen storage, one-half of the livers were subjected to 21°C for 24 h followed by a 15-d period of storage at −1°C. The other livers were kept in frozen storage (−29°C) during this 15-d period after which all livers were subjected to either 10 or 21°C temperatures. S. aureus counts did not change during the 15-d storage period at −1°C, whereas aerobic plate counts (APC) increased by over 3 log10 cycles. The low storage temperature plus the growth of competitor bacteria most likely prevented S. aureus from proliferating. When all livers were subjected to 24 to 144 h of storage at either 10 or 21°C, those that had been subjected to 15 d of slow surface thawing displayed a lower S. aureus count and higher APC than livers subjected to rapid thawing followed by holding at the high temperatures. This may mean that if livers become contaminated with substantial numbers of S. aureus before freezing, then rapid thawing coupled with high storage temperatures (more typical of meat merchandising in less developed countries) could allow for rapid S. aureus growth before competitor organisms increase in numbers.

Effects of Potassium Sorbate on Normal Flora and on Staphylococcus aureus Added to Minced Cod

1982 ◽  
Vol 45 (9) ◽  
pp. 824-828 ◽  
Author(s):  
DONALD J. LYNCH ◽  
NORMAN N. POTTER
Keyword(s):  
Staphylococcus Aureus ◽  
Storage Period ◽  
Inhibitory Effect ◽  
Potassium Sorbate ◽  
Normal Flora ◽  
Ph Changes ◽  
Normal Microflora ◽  
Enterotoxin Production ◽  
Plate Counts ◽  
Storage Temperatures

Minced cod and pasteurized minced cod, with and without 0.5% potassium sorbate, were subjected to abusive storage temperatures of 7 and 15°C. Staphylococcus aureus FRI 100 was inoculated into the cod before storage. Total aerobic plate counts (20 and 35°C), pH changes, S. aureus counts and the presence of thermonuclease were monitored throughout the studies. With the unpasteurized minced cod, potassium sorbate caused slightly lower aerobic plate counts (at 20 and 35°C) in the 7°C study over an 11-day storage period. Psychrotrophic organisms were inhibited to a slightly greater extent than were mesophilic organisms. Inoculated S. aureus was quickly outgrown by the normal microflora without or with sorbate. Similar results were obtained at the still more abusive temperature of 15°C over a storage period of 5 d, but the inhibitory effect of sorbate was less evident. Pasteurized minced cod, inoculated with S. aureus and stored at 15°C, showed a considerable difference in growth of S. aureus with and without sorbate. Potassium sorbate resulted in a markedly slower rate of growth of the pathogen and a substantial delay of several days in production of detectable levels of thermonuclease. This delay in nuclease production is indicative of a similar delay in enterotoxin production.

Effect of Storage Temperature on the Outgrowth and Toxin Production of Staphylococcus aureus in Freeze-Thawed Precooked Tuna Meat

2016 ◽  
Vol 79 (4) ◽  
pp. 620-627 ◽  
Author(s):  
AI KATAOKA ◽  
ELENA ENACHE ◽  
CARLA NAPIER ◽  
MELINDA HAYMAN ◽  
LISA WEDDIG
Keyword(s):  
Staphylococcus Aureus ◽  
Storage Temperature ◽  
Salt Content ◽  
Frozen Storage ◽  
Toxin Production ◽  
Sensory Profile ◽  
Katsuwonus Pelamis ◽  
Enterotoxin Production ◽  
Sample Composition ◽  
Plate Counts

ABSTRACT The aim of this study was to determine the time for a 3-log CFU/g outgrowth of Staphylococcus aureus and its toxin production in previously frozen precooked tuna meat (albacore [Thunnus alalunga] prepared as loin, chunk, and flake or skipjack [Katsuwonus pelamis] prepared as chunk and flake) held either at 21 or 27°C. A five-strain cocktail of enterotoxin-producing S. aureus was surface inoculated with ~103 CFU/g onto tuna samples. The experimental time–temperature conditions were designed to mimic common industry holding conditions. After a 3-h incubation at 37°C, inoculated samples were individually vacuum sealed and stored at −20°C for 4 weeks. Following frozen storage, samples were thawed to the target temperature (21 or 27°C) and then incubated aerobically. Growth of S. aureus in tuna was then monitored using Baird Parker agar; simultaneously, aerobic plate counts, enterotoxin production, and sensory profile (color and odor) were determined. The results showed that the time for a 3-log CFU/g increase was >20 h at 21°C and 8 to 12 h at 27°C for albacore, with toxin production observed at 14 to 16 h at 21°C and at 8 h at 27°C. A 3-log CFU/g increase for skipjack occurred at 22 to 24 h at 21°C and at 10 to 14 h at 27°C. The toxin production in skipjack started at 20 to 22 h at 21°C and at 8 to 10 h at 27°C. Toxin production was observed before a 3-log increase was achieved in albacore samples at 21°C. Under all conditions, toxins were detected when the cell density of S. aureus was 6 log CFU/g. Overall, significantly faster S. aureus growth was observed in albacore compared with skipjack (P < 0.05), possibly owing to differences in sample composition (e.g., pH and salt content). The data developed from this study can be used by the tuna industry to model the growth and enterotoxin production of S. aureus and to design manufacturing controls that ensure food safety.

Microbiological Characteristics of Beef Tongues and Livers as Affected by Temperature-Abuse and Packaging Systems

1982 ◽  
Vol 45 (6) ◽  
pp. 527-532 ◽  
Author(s):  
C. A. ROTHENBERG ◽  
B. W. BERRY ◽  
J. L. OBLINGER
Keyword(s):  
Staphylococcus Aureus ◽  
Clostridium Perfringens ◽  
Frozen Storage ◽  
Storage Period ◽  
Storage Conditions ◽  
Microbiological Characteristics ◽  
Packaged Beef ◽  
And Storage ◽  
Storage Temperatures ◽  
Chloride Film

Effects of various handling, packaging, temperature-abuse and storage conditions were determined on the microbiological characteristics of beef livers and tongues. These organs were evaluated: (a) initially following slaughter, (b) immediately following the frozen storage period of 2–4 weeks at −29°C and (c) following a simulated shipping-temperature abuse of 24 h at 22–28°C followed by 13 days of storage at −1 ± 0.5°C. Initial counts (log/cm2) of coliforms, coagulase-positive Staphylococcus aureus and Clostridium perfringens ranged from 0.19–1.37. Generally, neither freezing nor temperature-abuse had a significant effect on these microorganisms. Vacuum-packaged beef tongues and livers, generally, had lower bacterial counts than did either naked or polyvinyl chloride film-wrapped products. Generally, it was observed that abusive storage temperatures, in conjunction with the naked and film-wrapped packaging systems, appear to present potential microbial spoilage problems when compared with vacuum packaging.

Viability of Salmonella and Listeria monocytogenes in Delicatessen Salads and Hummus as Affected by Sodium Content and Storage Temperature

2012 ◽  
Vol 75 (6) ◽  
pp. 1043-1056 ◽  
Author(s):  
WALID Q. ALALI ◽  
DAVID A. MANN ◽  
LARRY R. BEUCHAT
Keyword(s):  
Listeria Monocytogenes ◽  
Storage Temperature ◽  
Storage Period ◽  
Sodium Concentration ◽  
Sodium Content ◽  
Initial Population ◽  
Ph Values ◽  
Plate Counts ◽  
Survival And Growth ◽  
And Storage

A study was conducted to determine survival and growth behavior of Salmonella and Listeria monocytogenes in commercially prepared mayonnaise-based potato salad, macaroni salad, and coleslaw and in hummus (initial mean pH values were 4.80 to 4.94, 4.18 to 4.31, 3.87, and 4.50 to 4.52, respectively) as affected by sodium concentration (133 to 364, 190 to 336, 146 to 272, and 264 to 728 mg/100 g, respectively) and storage at 4 or 10°C for up to 27 days. Salmonella did not grow in any of the test products. Initial populations (2.02 to 2.38 log CFU/g) decreased in coleslaw to undetectable levels (<1 CFU/25 g) within 13 days and in most formulations of macaroni salad within 20 to 27 days. Salmonella survived in highest numbers in potato salad and hummus. The presence of added sodium in macaroni salad stored at 4°C and hummus stored at 4 or 10°C appeared to protect Salmonella against inactivation. L. monocytogenes, at an initial population of 1.86 to 2.23 log CFU/g, did not grow in test products, but with the exception of coleslaw containing sodium at a concentration used in the standard (control) recipe, this pathogen was detected by direct plating (≥1.0 log CFU/g) in all products stored at 4 or 10°C for 27 days. L. monocytogenes populations were significantly (P < 0.05) lower in potato salad and hummus with no added sodium than in test products with added sodium after storage at 4°C. Sodium concentration did not markedly affect aerobic plate counts over the 27-day storage period. Results confirm that the acidic pH of mayonnaise-based salads and hummus is a major factor preventing growth and influencing rates of inactivation of Salmonella and L. monocytogenes. In the absence of added sodium, death of these bacteria may be more rapid. However, in general decreasing or increasing the sodium concentration in selected delicatessen salad and hummus recipes does not markedly affect the behavior of Salmonella and L. monocytogenes when products are stored at 4 or 10°C for up to 27 days.

scholarly journals Effect of storage temperatures on the quality parameters of fish condiment prepared from Thai pangus (Pangasianodon hypophthalamus)

2019 ◽  
Vol 17 (3) ◽  
pp. 417-423
Author(s):  
Md Ismail Hossain ◽  
Fatema Hoque Shikha ◽  
Nurun Naher
Keyword(s):  
Room Temperature ◽  
Storage Temperature ◽  
Ph Value ◽  
Bacterial Load ◽  
Frozen Storage ◽  
Storage Period ◽  
Quality Parameters ◽  
Fish Food ◽  
Pangasianodon Hypophthalmus ◽  
Storage Temperatures

Quality parameters of a fish/food product changes with the storage temperature. Therefore, the present study was carried out to evaluate the effect of different storage temperatures on the changes in chemical and microbiological parameters of fish condiment prepared from Thai pangus (Pangasianodon hypophthalmus). The study was conducted in the Department of Fisheries Technology Laboratory from October 2015 to September 2016.Standard methodologies for product preparation and other analyses (chemical and microbiological) with some modifications were followed. The results of the experiment showed that- irrespective of storage temperature the TVB-N value increased progressively with the lapse of storage period. At room temperature (28°C to 32°C), the values increased very rapidly in compare to those of refrigeration (5°C to 8°C) and frozen temperature (-18°C to -20°C). The TVBN value increased from 1.63±0.01 to 3.31±0.06, 3.18±0.02 and 2.02±0.02 mg/100g on day 15th at room, 90th at refrigeration and 120th at frozen storage temperature, respectively. On the other hand, the peroxide values increased from 2.80±0.10 to 6.08±0.10, 6.97±0.20 and 5.40±0.20 meq/kg of oil, on 15th at room, 90th at refrigeration and 120th at frozen storage temperature, respectively. Throughout the storage period, the pH values of fish condiment also changed at different temperatures. The pH value decreased from 5.24±0.01 to 4.75±0.05, 4.51±0.11 and 4.49±0.90, respectively on day 15th at room, day 90th at refrigeration and day 120th at frozen storage temperature. The bacterial load (CFU/g) in condiment was found to increase at room temperatures (from 2.2 ×104 to 2.6×107). However, the growth of bacteria was slower at refrigeration temperature (from 2.2 ×104 to 2.5×107) and at frozen temperature bacterial growth found negative (from 2.2 ×104 to 3.6×102). So, from the observation on the changes in different quality parameters at different storage temperatures, it could be concluded that, the shelf life of Thai pangus fish condiment at room temperature was shorter but at refrigeration temperature fish condiment may remain in acceptable condition more than 90 days and more than 120 days at frozen temperature. J Bangladesh Agril Univ 17(3): 417–423, 2019

Modeling the Effect of Water Activity, pH, and Temperature on the Probability of Enterotoxin A Production by Staphylococcus aureus

2016 ◽  
Vol 79 (1) ◽  
pp. 148-152 ◽  
Author(s):  
TIAN DING ◽  
YAN-YAN YU ◽  
CHENG-AN HWANG ◽  
QING-LI DONG ◽  
SHI-GUO CHEN ◽  
...  
Keyword(s):  
Staphylococcus Aureus ◽  
Water Activity ◽  
Storage Temperature ◽  
Probability Model ◽  
Toxin Production ◽  
Factors Affecting ◽  
Model Predictions ◽  
And Storage ◽  
Storage Temperatures ◽  
Good Agreement

ABSTRACT The objectives of this study were to develop a probability model of Staphylococcus aureus enterotoxin A (SEA) production as affected by water activity (aw), pH, and temperature in broth and assess its applicability for milk. The probability of SEA production was assessed in tryptic soy broth using 24 combinations of aw (0.86 to 0.99), pH (5.0 to 7.0), and storage temperature (10 to 30°C). The observed probabilities were fitted with a logistic regression to develop a probability model. The model had a concordant value of 97.5% and concordant index of 0.98, indicating that the model satisfactorily describes the probability of SEA production. The model showed that aw, pH, and temperature were significant factors affecting the probability of toxin production. The model predictions were in good agreement with the observed values obtained from milk. The model may help manufacturers in selecting product pH and aw and storage temperatures to prevent SEA production.

The effect of dissolved O2 on the changes occurring in the flavour of ultra-high-temperature milk during storage

1973 ◽  
Vol 40 (2) ◽  
pp. 169-177 ◽  
Author(s):  
J. G. Zadow ◽  
R. Birtwistle
Keyword(s):  
High Temperature ◽  
Storage Temperature ◽  
Marked Decrease ◽  
Uht Milk ◽  
Noticeable Improvement ◽  
High Storage Temperature ◽  
High Storage ◽  
Dissolved O2 ◽  
Storage Temperatures ◽  
Ultra High Temperature

SummaryUltra-high-temperature (UHT)-treated milks containing a range of dissolved O2 levels were prepared using both direct and indirect UHT processes. The O2 content of directly processed UHT milk had a significant influence on the changes in the level of cooked flavour in the product during storage over a 12-week period. At storage temperatures of 2 and 20°C, a noticeable improvement in flavour could be achieved by O2 control. In general, samples with a head-space sufficient to yield an initial of 60–100 mm were most preferred. The effect of O2 control on samples stored at 38°C was only minor when compared with the marked decrease in acceptability of flavour occurring due to the high storage temperature.Directly processed samples stored at 20°C all gelled at 14 weeks while those stored at 2°C showed no evidence of gelation after 36 weeks. Storage at 38°C gave rapid flavour deterioration, bitterness at 7 weeks and gelation at 10 weeks.All indirectly processed samples were found to be severely cooked under the conditions employed, and any differences in flavour due to differing O2 contents were masked by the intensity of this flavour.

scholarly journals Lifting and Overwinter Storage of White Pine in Southern Ontario

1985 ◽  
Vol 61 (6) ◽  
pp. 480-483 ◽  
Author(s):  
G. D. Racey ◽  
R. E. Hutchison ◽  
C. Glerum
Keyword(s):  
Cold Storage ◽  
Storage Temperature ◽  
Frozen Storage ◽  
Field Performance ◽  
Pinus Strobus ◽  
Forest Tree ◽  
White Pine ◽  
Southern Ontario ◽  
Temperature Regimes ◽  
Survival And Growth

A fall lifting and overwinter storage trial on 3+0 white pine (Pinus strobus L.) was carried out at St. Williams forest tree nursery (42° 40′N, 80° 25′W) during two consecutive years to study: (1) the degree hardening day (DHD) requirement for lifting; and (2) the effect of different storage temperature regimes: cold (1-4 °C) and frozen (−3 °C) on the performance of stock stored overwinter. Field performance was best if lifting for overwinter storage was delayed until after an accumulation of 125 DHD which is less than that required farther north. In some instances, seedlings lifted very late in the year had reduced survival and growth in the following year. Seedlings were ready for cold storage before being ready for frozen storage. Frozen storage is preferred owing to molding problems associated with cold storage.

Formation of Dimethylamine in Stored Frozen Sea Fish

1970 ◽  
Vol 27 (10) ◽  
pp. 1685-1690 ◽  
Author(s):  
C. H. Castell ◽  
Wanda Neal ◽  
Barbara Smith
Keyword(s):  
Frozen Storage ◽  
Microbial Spoilage ◽  
The Family ◽  
Sea Fish ◽  
High Storage ◽  
Storage Temperatures

In cod fillets undergoing deterioration during frozen storage, the dimethylamine content increases (and not the trimethylamine content as previously reported by us). There was no evidence to show an accumulation of dimethylamine in the muscle of frozen scallops, lobster, or shrimp that were purposely held at relatively high storage temperatures. It is suggested that for fish of the family Gadidae dimethylamine might be used as a measure of "frozen-storage deterioration" in much the same way as trimethylamine has been used as a measure of microbial spoilage in the unfrozen fish.

Nucleotide Degradation in Frozen Swordfish Muscle

1969 ◽  
Vol 26 (6) ◽  
pp. 1597-1603 ◽  
Author(s):  
W. J. Dyer ◽  
Doris I. Hiltz
Keyword(s):  
Fish Species ◽  
Arrhenius Plot ◽  
Frozen Storage ◽  
Storage Period ◽  
Taste Panel ◽  
Storage Quality ◽  
Inosine Monophosphate ◽  
Red Muscle ◽  
Nucleotide Degradation ◽  
Storage Temperatures

In frozen swordfish steaks, inosine monophosphate (IMP) dephosphorylation was active at − 8 C and less so at − 18 C. A loss of IMP at − 26 C became apparent during a 2-year storage period. Rates of loss were about 0.24 and 0.029 μmoles per g per week at − 8 and − 18 C, the Arrhenius plot being linear over the temperature range 0 to − 26 C. Inosine ribohydrolase was less active; nevertheless, about 2.5 μmoles per g of hypoxanthine accumulated in 2 years at − 8 C. Taste panel tests indicated a storage life of 3 months at − 8 C, 9 months at − 18 C, and several years at − 26 C. The loss of IMP was slightly slower than the associated taste panel score decrease and thus may have potential as an indicator of frozen storage quality in some fish species, though it did not prove useful for swordfish. Hypoxanthine formation at low storage temperatures is sufficiently slow to allow use of hypoxanthine as an index of prefreezing quality; however, red muscle must not be included in the sample because of its high initial hypoxanthine content, about 1.9 μmoles per g.

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