Vacuum-packaged Beef Research Articles

The effective product life of vacuum-packaged beef imported into Saudi Arabia by sea, as assessed by chemical, microbiological and organoleptic criteria

Five transport and storage trials were conducted on commercial shipments of vacuum-packaged beef half striploins imported into Saudi Arabia by sea from Australia, New Zealand and the Republic of Ireland. The cold chains, from packaging to the end of chilled storage in Saudi Arabia, were monitored using miniature electronic data loggers placed in cartons of striploins. Development of spoilage microfloras was followed from packaging to trial end using a differential aerobic plate count technique. Changes in meat pH, total volatile nitrogen (TVN) and free fatty acid (FFA) content were determined over the storage period. Sensory evaluations to identify spoilage conditions and to determine consumer acceptability were also conducted over the course of storage in Saudi Arabia. Results indicated that aerobic plate counts, TVN and FFA were all unsuitable as indicators of the fitness, or acceptability of vacuum-packaged beef for human consumption. Under good but commercially realistic conditions (i.e. normal ultimate pH beef, initial microbial contamination at packaging of less than 10 3/cm 2, packaging, film oxygen transmission rate less than 40 ml/m 2/24 h/atm at 23°C and 90% R.H., and mean product temperature during transport and storage of 0°C), vacuum-packaged beef transported by sea has an anticipated product life of at least 90 days measured from the date of slaughter. Under the conditions just stated, deterioration of meat texture resulting from excessive aging rather than the onset of overt microbial spoilage will limit the effective product life of vacuum-packaged beef.

Polyvinylchloride-packaged loin strip steaks from vacuum-packaged beef strip loins decontaminated with lactic acid and stored for up to 126 days

Aerobic plate counts (APCs), presence/ absence of Listeria monocytogenes and Salmonella spp., and visual color evaluations were used to determine the microbiological and display quality of steaks fabricated from beef strip loins sprayed with lactic acid (1.5% v/v) or water before, after, o r both before and after vacuum storage (14, 28, 56, 84, or 126 days) at either 30 ÌŠor 36 ÌŠF compared to nonsprayed or nonstored controls. Lactic acid applied pre- and poststorage (126 days) at 30 ÌŠF reduced APCs of steak s up to 2 log (99%). L. monocytogenes and Salmonella spp. were absent from all steaks. Lactic acid caused slightly more rapid color deterioration, resulting in slightly shorter display-life for steaks.

Polyvinylchloride-packaged loin strip steaks from vacuum-packaged beef strip loins decontaminated with lactic acid and stored for up to 126 days (1994)

Aerobic plate counts (APCs), presence/ absence of Listeria monocytogenes and Salmonella spp., and visual color evaluations were used to determine the microbiological and display quality of steaks fabricated from beef strip loins sprayed with lactic acid (1.5% v/v) or water before, after, o r both before and after vacuum storage (14, 28, 56, 84, or 126 days) at either 30E or 36EF compared to nonsprayed or nonstored controls. Lactic acid applied pre- and poststorage (126 days) at 30EF reduced APCs of steak s up to 2 log (99%). L. monocytogenes and Salmonella spp. were absent from all steaks. Lactic acid caused slightly more rapid color deterioration, resulting in slightly shorter display-life for steaks.

Reduction of Listeria monocytogenes in Precooked Vacuum-Packaged Beef Using Postpackaging Pasteurization

Precooked beef loin chunks were inoculated separately with three strains of Listeria monocytogenes (Scott A, 101M, and 103M). Uninoculated chunks served as controls. All chunks were vacuum packaged after inoculation. Half were not pasteurized and half were pasteurized in 85°C water for 16 min. All samples were stored at 4°C for up to 85 d and examined periodically. Pasteurization reduced all microflora and significantly reduced populations of three strains of L. monocytogenes on the surface and in the broth of the precooked beef chunks for 85 d of refrigerated storage as determined by direct plating procedures. All three strains of L. monocytogenes were recovered from the inoculated pasteurized beef using enrichment. Uninoculated chunks were positive for Listeria spp. which were primarily Listeria welshimeri. Without pasteurization, microflora increased 5- to 6-fold within 14 d of storage. Populations of Scott A and 101M strains of L. monocytogenes increased significantly within 7 d. After 14 d, populations of all three strains did not differ from initial levels and remained unchanged for the remainder of the storage period.

Using Laboratory Experimental Auctions in Marketing Research: A Case Study of New Packaging for Fresh Beef

This paper illustrates the use of laboratory experimental auctions in a pretest market research program for new products. We review the experimental auctions literature, discuss the range of auction mechanisms available and present the advantages and disadvantages of using a particular mechanism for a laboratory pretest market. We then present a step-by-step example of how a theoretically incentive compatible auction mechanism (fifth-price, sealed-bid) was used in a laboratory pretest market for vacuum-packaged beef. Based on the illustration, we discuss the potential for using laboratory experimental auctions in pretest market research. We present the limitations that may be encountered in such applications and outline research aimed at improving the behavioral properties of the technique.

Biogenic Amine Formation in Fresh Vacuum-Packaged Beef During Storage at 1°C for 120 Days

Undesirable changes in vacuum-packaged beef products during prolonged storage can present a problem to some consumers. Bacterial proteolysis and decarboxylation can release pressor amines, such as tyramine and histamine, that can be toxic when ingested by individuals taking monoamine oxidase-inhibiting drugs. This study determined the effect of carcass decontamination on bacterial growth and biogenic amine production in vacuum-packaged subprimals. Beef carcasses were treated with 200 ppm chlorine or 3% lactic acid sprays, fabricated, vacuum packaged, and stored at 1°C. Samples were evaluated up to 120 d for amine concentrations, total aerobic counts, and lactic acid bacteria. Of all the amines monitored, only tyramine was consistently detected over the course of the study. Significant levels of tyramine were detected starting at day 20 of storage in all treatments and controls. By day 60, the levels had increased to about 50 μg/g and continued to increase to about 180 μg/g by 120 d of storage. Tryptamine was detected in some samples by 60 d of storage, but the levels were variable and did not follow any trend. Initial aerobic plate counts ranged from 10-200 CFU/cm2, whereas lactic acid bacteria counts were from 6-46 CFU/cm2. Bacterial numbers increased exponentially until about day 60, when they leveled off at between 106-107 CFU/cm2, with no differences between any of the treatments and/or controls. Although the vacuum-packaged beef was organoleptically acceptable up to day 60 (day 90 for some samples), it could pose some risk to individuals sensitive to biogenic amines if the product is stored at 1°C or higher for 60 d or more.

Efficiency of a Commercial Process for the Storage and Distribution of Vacuum-Packaged Beef

The storage efficiency of a commercial processed for the distribution of vacuum-packaged beef by road was assessed using a temperature function integration technique. Temperature histories were collected from representative samples of product units during the in-plant storage of product before its dispatch and during carriage of product on journeys lasting 2 or more days. The temperature histories were integrated with respect to models relating the growth of psychrotrophic enterobacteria to temperature. The growth of the organisms was considered indicative for the development of spoilage flora. During in-plant storage, the lag induced by vacuum packaging was calculated to be nearly or wholly resolved for the reference bacteria on 31 % of the product units. Assuming the worst case situation of full lag resolution of the bacteria in all product units by the time of loading to transport, proliferations calculated for the periods of transport ranged from 3 to 13 generations. From that data, it was estimated that the product would achieve on average only about 25% of the potential storage life. The major factor contributing to poor storage performance was the failure to equilibrate product to near the optimum storage temperature before the product was loaded to transport.

Taxonomic studies on a psychrophilic Clostridium from vacuum-packed beef: Description of Clostridium estertheticum sp. nov.

Taxonomic studies were performed on an anaerobic Gram-positive, spore-forming, psychrophilic bacterium originally isolated from spoiled vacuum-packed refrigerated beef. Based on the present finding it is proposed that this unknown psychrophilic bacterium be classified as a new species of the genus Clostridium, as Clostridium estertheticum sp. nov. The type strain is NCIMB 12511.

Microbiological characteristics of precooked, vacuum-packaged uncured beef and pork

Microbiological examination of 29 packages of precooked, vacuum-packaged beef and pork products purchased at local and regional supermarkets along with 110 packages of precooked, vacuum-packaged, sliced roast beef obtained from a major meat processor did not disclose the presence of Escherichia coli, coagulase-positive Staphylococcus aureus, Clostridium perfringens or Salmonella. The effects of storage temperature and length of storage on the microflora of 110 packages of sliced roast beef were determined at specific intervals of storage up to 84 days at 1° and 5°C, and up to 28 days at 10°C. The microflora of samples stored at 1° and 5°C was dominated by Lactobacillus spp. when examined on day 28 and throughout the remainder of the 84-day test period. The microflora of samples held at 10°C was dominated by Lactobacillus spp. until late in storage when Hafnia alvei became a major portion of the bacterial population. Precooked, sliced roast beef had a longer shelf life in laboratory controlled evaluations when stored at 1°C as opposed to 5° or 10°C.

Amines in fresh beef of normal pH and the role of bacteria in changes in concentration observed during storage in vacuum packs at chill temperatures

The amine content of fresh and vacuum-packaged beef of normal pH stored at 1 degree C was evaluated by high performance liquid chromatography of dansyl derivatives. Fresh samples contained five amines, viz. putrescine, cadaverine, histamine, spermine and spermidine. Development of a natural spoilage flora during storage led to increases in concentration of putrescine and cadaverine and the production of a sixth amine, tyramine. Pure culture meat inoculation experiments showed tyramine formation to be restricted to lactobacilli and to strains of Lactobacillus divergens and Lact. carnis in particular; strains of leuconostocs, Enterobacteriaceae, Pseudomonas spp. and Brochothrix thermosphacta were negative. Production of tyramine at cell densities less than log10 6/cm2 indicated its potential as an objective measure of acceptability/spoilage.

CHANGES IN TENDERNESS DURING AGING OF VACUUM-PACKAGED BEEF

The variation of tenderness during aging of vacuum-packaged beef at different storage temperatures (0, 4, 10 and 13°C) was determined. Tensile and Warner Bratzler (WB) shear measurements were used to assess the tenderness of raw and cooked beef (M. semitendinosus). Coefficients of variation corresponding to each method demonstrated the usefulness of the WB shear test with cooked beef. An exponential decay equation was used to quantify changes in beef tenderness during aging; rate constants and activation energies for each method were calculated. The model was adequate to represent the time dependence of different aging indicators: Biochemical Index of Myofibrillar Aging (BIMA) and Yield Point (YP).

Effect of Film Oxygen Transmission Rate on Lean Color and Microbiological Characteristics of Vacuum-Packaged Beef Knuckles

Seventy-two beef knuckles were packaged (n = 12) in each of six different bag types with oxygen transmission rates (OTR) of 1, 10, 12, 13, 30 and 400 cc/m2/24 h at 4°C and 100% relative humidity to study brown discoloration of knuckles during refrigerated storage. Knuckles in bag types of OTR of 1 and 12 cc did not discolor as compared to those in bags with higher OTR (30 and 400 cc) probably due to differences in oxygen tension in the package and in the types of bacteria present. Deterioration of lean color of knuckles in some bag types of low OTR appeared associated with large percentages of Leuconostoc mesenteroides in the microflora.

Bacterial sources of putrescine and cadaverine in chill stored vacuum-packaged beef.

Of the meat strains of streptobacteria, leuconostocs, Enterobacteriaceae and Brochothrix thermosphacta tested, only Hafnia alvei and Serratia liquefaciens showed diamine-producing potential during growth in pure culture on beef stored in vacuum packs at 1 degree C. Both organisms produced cadaverine at concentrations similar to those reported previously in naturally contaminated beef stored under the same conditions. Putrescine concentrations produced by the two organisms, however, were an order of magnitude lower. During the growth on beef of either H. alvei or S. liquefaciens in mixed culture with arginine-utilizing strains of streptobacteria, putrescine as well as cadaverine concentrations were similar to those detected in naturally contaminated samples.

Toxin Production by Clostridium botulinum and Organoleptic Changes in Vacuum-Packaged Raw Beef

Vacuum-packaged beef, inoculated with Clostridium botulinum spores of types A and B and incubated at 25°C, was monitored for the production of toxin and for changes in appearance and odor. Toxin was detected first after 6 d of incubation and was always accompanied by significant organoleptic changes when compared to meat stored at 4°C. Uninoculated meat samples stored at 25°C remained non-toxic, whereas their sensory scores, in particular with respect to appearance, were similar to those of the inoculated samples.

Classification of some lactic acid bacteria from vacuum-packed meats by direct probe mass spectrometry.

The technique of direct probe mass spectrometry (DPMS) has been applied to the classification of 40 strains of lactic acid bacteria from refrigerated vacuum-packed beef, pork, lamb and bacon. Relationships between strains were examined by multi-variate statistical techniques using sets of ions selected for reproducibility and sample discrimination. Five groups were distinguished which corresponded closely to those detected in a previous numerical taxonomic study. Two groups contained all 12 representatives of a cluster of unidentifiable non-aciduric streptobacteria whose sub-division is supported by other taxonomic evidence. All twenty-one strains from a cluster of aciduric streptobacteria provisionally identified with Lactobacillus sake were contained in two further groups. The sub-division of these aciduric strains revealed by DPMS has not been verified by other techniques and requires further investigation. The fifth group contained Leuconostoc strains. The study demonstrates the value of DPMS in confirming and clarifying classification schemes obtained by conventional methods.

Vacuum-Packaged Trimmings as a Source for Ground Beef Patties: Changes During One Year of Frozen Storage

Vacuum-packaged beef trimmings were stored for four time periods of 0, 1, 2 and 3 wk (4 lots) at 5°C. After the storage period, the four lots of trimmings were evaluated for chemical, microbial and sensory properties. Each lot was then made into beef patties. Two lots of patties (0 and t wk of storage at 5°C) were further stored at −18°C for 0, 3, 6, 9 and 12 months and used to determine sensory properties. The two lots prepared from trimmings stored for 2 and 3 wk were evaluated for chemical properties at 0, 6, 9 and 12 months of −18°C frozen storage. Patties prepared from vacuum-packaged beef trimmings stored for 2 and 3 wk had significantly lower sensory ratings as compared to ratings for patties made from trimmings stored for 0 or 1 wk. Microbial counts indicated that bacterial action could be more important than oxidative rancidity as the cause for these changes. Increased length of frozen storage time did not markedly affect sensory properties.

Microbial Growth in Carcasses and Boxed Beef During Storage

Fresh western-Canadian beef delivered to an eastern-Canadian terminal (Quebec City, Qc) was evaluated for microbial contamination of carcasses (front and rear portions) and of boxed beef (heat and clip-sealed). Total microbial counts during a 12-month sampling varied from log10 values of 6.28 in front portions of carcasses to 7.10 in clip-sealed boxed beef. Lactobacillus counts were higher in clip-sealed boxed beef (6.93) than in the front portion of carcasses (4.39). Total and fecal coliform counts were much higher in vacuum-packed beef than in carcass beef (4.42 and 0.97, respectively). Microbial species isolated from carcasses and vacuum-boxed beef varied markedly, with Pseudomonas spp. as predominant in carcasses and a mixed flora of Pseudomonas spp., Lactobacilli spp. and Aeromonas spp. in vacuum-packed beef.

A numerical taxonomic study of lactic acid bacteria from vacuum-packed beef, pork, lamb and bacon.

A numerical taxonomic study using 79 unit characters has been performed on 100 isolates of lactic acid bacteria from refrigerated vacuum-packed beef, pork, lamb and bacon. Three clusters were observed at 78% S which contained all the strains apart from three unidentifiable streptobacteria, one Leuconostoc, and one strain of Pediococcus pentosaceus. One cluster (III) consisted of only one strain of Leuc. paramesenteroides and six unidentifiable Leuconostoc strains. The two largest clusters (I and II) were both composed entirely of streptobacteria. Cluster I contained 31 strains (G + C content 33.2-36.9 moles%) which were not identifiable with any described species. Cluster II contained 57 strains (G + C content 40.7-43.7 moles %) which were provisionally identified with Lactobacillus sake or Lact. bavaricus according to the lactic acid isomer produced. The division of nearly all the streptobacteria into two clearly defined clusters has resolved problems which have existed in the classification of lactic acid bacteria from vacuum-packed meat.

Microbial Growth on Fat and Lean Surfaces of Vacuum‐Packaged Chilled Beef

ABSTRACT Brochothrix thermosphacta, Enterobacteriaceae and the Pseudomonas‐Moraxella group grew more rapidly on the fat than on the lean surfaces of chilled vacuum‐packaged beef striploins of pH 5.45–5.85. On the fat, both B. thermosphacta and Enterobacteriaceae grew to outnumber the Pseudomonas‐Moraxella. When Enterobacteriaceae and B. thermosphacta were present initially in about equal numbers, Enterobacteriaceae outgrew B. thermosphacta on both the fat and the lean surfaces of packs stored at 5°C. At 1°C the growth rate of the Enterobacteriaceae was greatly reduced. As a result, on the fat at 1°C, B. thermosphacta grew considerably faster than did the Enterobacteriaceae.

Lactic acid bacteria of meat and meat products.

When the growth of aerobic spoilage bacteria is inhibited, lactic acid bacteria may become the dominant component of the microbial flora of meats. This occurs with cured meats and with meats packaged in films of low gas permeability. The presence of a flora of psychrotrophic lactic acid bacteria on vacuum-packaged fresh chilled meats usually ensures that shelf-life is maximal. When these organisms spoil meats it is generally by causing souring, however other specific types of spoilage do occur. Some strains cause slime formation and greening of cured meats, and others may produce hydrogen sulphide during growth on vacuum-packaged beef. The safety and stability of fermented sausages depends upon fermentation caused by lactic acid bacteria. Overall the presence on meats of lactic acid bacteria is more desirable than that of the types of bacteria they have replaced.