Treatment With High-Hydrostatic Pressure, Activated Film Packaging With Thymol Plus Enterocin AS-48, and Its Combination Modify the Bacterial Communities of Refrigerated Sea Bream (Sparus aurata) Fillets

Abstract

The aim of this study was to determine the impact of activated plastic films with thymol and enterocin AS-48 and high-hydrostatic pressure (HP) treatment on the bacterial load and bacterial diversity of vacuum-packaged sea bream fillets under refrigerated storage for 10 days. The activated film and the HP treatment reduced aerobic mesophiles viable counts by 1.46 and 2.36 log cycles, respectively, while the combined treatment achieved a reduction of 4.13 log cycles. HP and combined treatments resulted in longer delays in bacterial growth. Proteobacteria were the dominant phyla in sea bream fillets. The relative abundance of Firmicutes increased by the end of storage both in controls and in samples treated by HP singly or in combination with the activated films. The predominant operational taxonomic units (OTUs) found at time 0 in control samples (Listeria, Acinetobacter, Pseudomonas, Enterobacteriaceae, Chryseobacterium) rapidly changed during storage (with an increase of Vibrio, Photobacterium, and Shewanella together with Cloacibacterium and Lactobacillales by the end of storage). The activated film and the HP treatment induced drastic changes in bacterial diversity right after treatments (with Comamonadaceae, Methylobacterium, Acidovorax, and Sphingomonas as main OTUs) and also induced further modifications during storage. Bacterial diversity in activated film samples was quite homogeneous during storage (with Vibrio, Photobacterium, and Shewanella as main OTUs) and approached control samples. HP treatments (singly or in combination with activated films) determined a high relative abundance of Acinetobacter (followed by Pseudomonas and Shewanella) during early storage as well as a higher relative abundance of lactic acid bacteria by the end of storage. The results indicate that the complex dynamics of bacterial populations in the refrigerated sea bream fillets are markedly influenced by treatment and antimicrobials applied.

Encapsulation Systems for Antimicrobial Food Packaging Components: An Update

“…Taking into consideration that bacteriocins are more effective against Gram-positive bacteria and possess a narrow antimicrobial spectrum, they are used in food packaging in combination with other antimicrobials or preservation techniques. Over the last five years, the use of enterocin AS-48 [47], bacteriocins-like substances [48] or bacteriocin-producing strains [49] with modified atmosphere packaging or high hydrostatic pressure has yielded improved results in the packaging of chilled food products. Furthermore, bacteriocin combination with other antimicrobials such as thymol [47,50], carvacrol [50], EDTA [51] or chitosan [17,52] have also improved their antibacterial action in food products such as meat and fish.…”

High pressure processing combined with selected hurdles: Enhancement in the inactivation of vegetative microorganisms

“…Ortega Blázquez et al. (2018) reported that the combination of HPP (300 MPa/23 °C/5 min) and enterocin AS‐48 and thymol through active package reduced the total aerobic bacteria in sea bream fillets by 4.13 log cycles, while single treatment induced 2.36 or 1.46 log cycles, respectively. Pérez‐Baltar et al.…”

“…found that more than 5 log reduction of both L. innocua and E. coli in carrot juice was achieved by the combination of HPP (300 MPa/35 • C/2 min) and nisin (0.0025%, w/w), compared with less than 1 log reduction in the absence of nisin. OrtegaBlázquez et al (2018) reported that the combination of HPP (300 MPa/23 • C/5 min) and enterocin AS-48 and thymol through active package reduced the total aerobic bacteria in sea bream fillets by 4.13 log cycles, while single treatment induced 2.36 or 1.46 log cycles, respectively Pérez-Baltar et al (2019). reported that HPP (450 MPa/18…”

Natural Plant-Derived Chemical Compounds as Listeria monocytogenes Inhibitors In Vitro and in Food Model Systems

“…In samples treated with the activated film, bacteria were reduced to 0.00% of all the microorganisms at day 0. After 10-day storage relative abundance of Listeria genus in the treated and untreated samples were of 0.09% and 0.79%, respectively [ 116 ].…”