Effect of beef long-storage under different temperatures and vacuum-packaging conditions on meat quality, oxidation processes and microbial growth.

BACKGROUND: The global beef market demands the meat industry to ensure product quality and safety in markets that are often very distant. The present study aimed to evaluate the effects of chilled (CH, 120 d) and chilled-then-frozen (CHF, 28 d + 92 d) storage conditions of beef vacuum packaged (VP) and vacuum packaged with antimicrobial (VPAM) on meat quality, oxidative status and microbial loads. Treatments resulted from the combination of storage condition and packaging type: VP + CH, VP + CHF, VPAM + CH and VPAM + CHF. RESULTS: Warner-Bratzler shear force values decreased in all treatments after 28 d of chilling. Except for VP + CH, L* values (lightness) of meat color did not differ in each treatment as the storage time increased. Meat from VP + CH had greater a* values than CHF treatments on day 120 of storage. A consumer panel did not detect differences in tenderness, flavor and overall liking between VP and VPAM beef, but they preferred CHF steaks rather than CH beef. TBARS values did not differ between VP and VPAM and between CH and CHF at any time during the storage period. At the end of storage time, all treatments except VP + CHF presented a greater concentration of thiols than at 48 h post-mortem. On day 120 of storage, VP + CH had greater catalase enzyme activity than CHF treatments while VP + CH and VP + CHF showed a greater superoxide dismutase activity than VPAM + CHF. Storage condition (CH or CHF) had a greater impact on microbial counts than the type of packaging. CONCLUSION: Freezing meat after an ageing period represents a suitable strategy to extend beef storage life without a detrimental impact on its quality. © 2023 The Authors. Journal of The Science of Food and Agriculture published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.

Microbiological Changes during Long-Storage of Beef Meat under Different Temperature and Vacuum-Packaging Conditions.

We evaluated a combination of two temperatures and two packaging materials for long-term storage of vacuum-packaged (VP) beef striploins. Microbial populations and microbiome composition were monitored during refrigerated storage (120 days between 0-1.5 °C) and refrigerated-then-frozen storage (28 days between 0-1.5 °C then 92 days at -20 °C) under low-O2 permeability VP and high-O2 permeability VP with an antimicrobial (VPAM). Pseudomonas (PSE) and Enterobacteriaceae (EB) counts in VPAM samples were significantly higher (p < 0.05) than in VP samples at 28, 45, 90, and 120 days of storage. Microbiome data showed that bacteria of the genera Serratia and Brochothrix were more abundant in VPAM samples at 120 days, while lactic acid bacteria (LAB) dominated in VP samples. Frozen temperatures inhibited microbial growth and maintained a relatively stable microbiome. Refrigerated and frozen VPAM samples showed the greatest difference in the predicted metabolic functions at the end of storage driven by the microbiome composition, dominated by PSE and LAB, respectively. Although no signs of visible meat deterioration were observed in any sample, this study suggests that VP meat refrigerated and then frozen achieved better microbiological indicators at the end of the storage period.

Chemical characterisation and in vitro anthelmintic activity of phenolic-rich extracts from the leaves and branches of Maytenus ilicifolia, a native plant from South America.

Free (epi) catechin, quercetin, (epi) gallocatechin, flavonol glycosides and condensed tannins were identified according to their molecular mass, characteristic product ions and retention times in extracts obtained from leaves and branches of Maytenus ilicifolia (Congorosa) by mass spectrometry. The in vitro anthelmintic activity against cattle gastrointestinal nematodes of Congorosa extract was determined using the Egg Hatch Inhibition Assay. Additionally, commercial quercetin, gallocatechin and epicatechin were evaluated. Although total phenolics, total tannins and condensed tannins contents were lower in branches extract than in leaves extract, the EC50 were 0.065 mg/mL and 0.890 mg/mL for branches and leaves extract, respectively. Moreover, the use of polyvinylpyrrolidone as a blocking agent of tannins, did not change significantly the EC50 for branches extract, but significantly changed for leaves extract. Quercetin and gallocatechin EC50 values were in the range 0.03-0.05 mg/mL and epicatechin showed 100% inhibition of the egg hatching process at 0.004 mg/mL.