Work

Recovered Bacteria Associated with Gas Accumulation in Vacuum-Packaged Fresh Kosher Ground Beef Stored at Refrigeration Temperature

Year: 2025

Type: article

Abstract: • Facility environmental samples indicated contamination sources throughout production. • Slight off-odor and hydrogen sulfide detected as early as 5 d at 2–4 °C. • Lactic acid bacteria and Enterobacteriaceae were the most often isolated and identified. • L. mesenteroides , L. curvatus , and S. liquefaciens were the most recovered gas producers. Vacuum packaging and storage at chilled temperatures are commonly used to prolong the shelf life of meat. Under these conditions, cold-tolerant facultatively anaerobic spoilage microorganisms not only can grow but the conditions are more favorable for their growth because these conditions eliminate competition from cold-tolerant aerobic microorganisms. The objective of this study was to identify bacteria that caused gas formation and accumulation in vacuum-packaged refrigerated fresh kosher ground beef as well as from processing plant environment samples. A total of 87 vacuum-packaged ground beef (∼454 g size) and 33 environmental samples were received from a kosher processing plant. The initial populations of aerobic bacteria (AB), psychrotrophic bacteria (PSYB), Enterobacteriaceae (EB) increased by 0.58–1.09 log CFU/g, while the population of lactic acid (LAB) increased 3.18 log CFU/g after 5d at 2–4 °C. After 5 d storage at 2–4 °C, 34% of the packages exhibited gas accumulation. The accumulated gas reacted with lead acetate and formed a brown-black color indicating hydrogen sulfide (H 2 S) formation, and the ground beef had a slight off-odor. Lactococcus lactis , Enterobacter cloacae , and Klebsiella oxytoca were the most isolated from environmental samples. Based on the results from the present study, the potential bacteria responsible for gas accumulation and distention of the vacuum-packaged ground beef were Leuconostoc mesenteroides (LAB), Lactobacillus curvatus (LAB), and Serratia liquefaciens (EB). The bacterial strains isolated from 5 d storage distended packages after 5 d storage were dominantly LAB, while the bacterial strains isolated after 56 d storage were mainly EB. These results indicated that LAB are potentially responsible for gas formation that occurs early postpackaging.

Source: Journal of Food Protection

DOI: 10.1016/j.jfp.2025.100493

Authors: Norasak Kalchayanand, Mohammad Koohmaraie, Tommy L. Wheeler

Institutions: Agricultural Research Service, United States Department of Agriculture, Roman L. Hruska U.S. Meat Animal Research Center

Language: English

Topic: Meat and Animal Product Quality

Subfield: Animal Science and Zoology

Field: Agricultural and Biological Sciences

Domain: Life Sciences

SDG: Zero hunger

Open Access status: gold

Estimated APC paid: $2,300