Identification of an N-terminal formylated, two-peptide bacteriocin from Enterococcus faecalis 710C.

Enterococcus faecalis 710C, isolated from beef product, has a broad antimicrobial activity spectrum against foodborne pathogens. Two bacteriocins, enterocin 7A (Ent7A) and enterocin 7B (Ent7B), were purified from the culture supernatant of E. faecalis 710C and characterized using matrix-assisted laser desorption ionization-time-of-flight mass spectrometry and electrospray infusion tandem mass spectrometry analyses.

Effect of low temperature on stability of theta-type plasmids in Carnobacterium maltaromaticum.

The heterologous production of useful peptides such as bacteriocins by lactic acid bacteria (LAB) has been studied for use in the biopreservation of foods. Recombinant plasmids can suffer drawbacks such as segregational instability affecting the production of these peptides in certain environments such as absence of selective pressure or low temperature. The link between growth temperature characteristics of parental strains and stability of theta-type plasmids at a low temperature was investigated.

Production of piscicolin 126 by Carnobacterium maltaromaticum UAL26 is controlled by temperature and induction peptide concentration.

Carnobacterium maltaromaticum UAL26 produces the antimicrobial peptides (bacteriocins) piscicolin 126, first isolated from C. maltaromaticum JG126, and carnobacteriocin BM1, first isolated from C. maltaromaticum LV17.

Characterization of the theta-type plasmid pCD3.4 from Carnobacterium divergens, and modulation of its host range by RepA mutation.

The complete nucleotide sequence of the 3475 bp plasmid pCD3.4 from Carnobacterium divergens LV13, which encodes the bacteriocin divergicin A, was determined. Nucleotide sequence, deletion and complementation analyses revealed the presence of a trans-acting replication protein, RepA, and DNA sequences involved in plasmid replication and copy-number control.

Enterococci in foods--a conundrum for food safety.

Enterococci form part of the lactic acid bacteria (LAB) of importance in foods. They can spoil processed meats but they are on the other hand important for ripening and aroma development of certain traditional cheeses and sausages, especially those produced in the Mediterranean area. Enterococci are also used as human probiotics.

Purification and characterization of brochocin A and brochocin B(10-43), a functional fragment generated by heterologous expression in Carnobacterium piscicola.

Brochothrix campestris ATCC 43754 produces a heat-stable, two-component, nonlantibiotic, class IIb bacteriocin, brochocin C (BrcC), that is active against a broad range of gram-positive bacteria, including spores of Clostridium botulinum. An improved purification method was developed for BrcC, in which n-butanol and chloroform extraction are used. Mass spectral characterization of the two components, brochocin A (BrcA) and brochocin B (BrcB), showed that both components are excreted into the medium by B.

Characterization of the genetic locus responsible for production and immunity of carnobacteriocin A: the immunity gene confers cross-protection to enterocin B.

Carnobacteriocin A (CbnA) is a regulated bacteriocin produced by Carnobacterium piscicola LV17A that is encoded on a 72 kb plasmid. A 10.0 kb fragment from this plasmid that contained information necessary for bacteriocin production and immunity was cloned and sequenced.

Potential for Use of Bacteriocin-Producing Lactic Acid Bacteria in the Preservation of Meats.

Bacterial spoilage and safety are major concerns in the marketing of raw and processed meats. When meat is packaged under modified atmosphere with elevated levels of carbon dioxide (including vacuum packaging), the prevailing microflora of meat is changed from aerobic, putrefactive bacteria to lactic acid bacteria. Some "new generation" convenience foods rely almost entirely on refrigeration for assurance of safety against growth of pathogenic bacteria.

Changes in Microbial Parameters and Gas Composition During Modified Atmosphere Storage of Fresh Pork Loin Cuts.

The storage life of modified atmosphere packaged pork loin cuts in 40% CO and 60% N was determined at -1, 4.4, and 10°C in three packaging films with oxygen transmission rates (OTR) of 0.0, 12.

Storage Life of Selected Meat Sandwiches at 4°C in Modified Gas Atmospheres.

The refrigerated storage life of selected meat sandwiches packed in elevated carbon dioxide atmospheres with air or nitrogen was studied by acceptability scores of untrained panelists and by microbiological analysis. Commercially produced sandwiches, including processed meats, roast beef and hamburgers, were packed in gas impermeable film with 50% CO and 50% air, stored at 4°C, and compared with a frozen reference sample. Processed meat products were still acceptable up to 35 d storage, roast beef for 28 to 35 d storage, and hamburger for only 14 d.

Microbial Quality of Vacuum Packaged Sliced Ham .

A total of 60 paired samples of vacuum packaged sliced ham was purchased at retail stores and analyzed for microbial quality as new (less than 10 days from manufacture) and old product (held to manufacturer's pull date at 4 C). Microbial counts of new product were variable, but at the product pull date, counts reached 10 per g. Differences in microbial load were noted between manufacturers.

Food Poisoning Potential of Artificially Contaminated Vacuum Packaged Sliced Ham in Sandwiches .

Ham sandwiches inoculated with a mixture of five enteropathogenic bacteria, Bacillus cereus , Clostridium perfringens . Escherichia coli , Salmonella typhimurium and Staphylococcus aureus , were held at 30, 21 and 4 C for up to 24 h. Food poisoning potential was judged by the growth and survival of the inoculated pathogens.