Survival of Salmonella on Red Meat in Response to Dry Heat

Abstract

Red meat is associated with Salmonella outbreaks resulting in negative impacts for the processing industry. Little work has been reported on the use of dry heat as opposed to moist heat against Salmonella on red meat. We determined the effect of drying at 25°C and dry heat at 70°C with ~10% relative humidity (RH) for 1 h against eleven Salmonella strains of multiple serovars on beef, lamb, goat, and rubber as an inert surface. Each strain at ~108 cfu/ml was inoculated (100ul) onto ±1g (1cm2) of each surface and allowed to attach for 15 min in a microcentrifuge tube. Samples were then exposed to 70°C and 25°C with ~10% RH in a heating block. Surviving Salmonella numbers on surfaces were enumerated on a thin layer medium. If numbers were below the limit of detection (LOD), (2.01 log cfu/cm2), Salmonella cells were enriched before plating to determine the presence of viable cells. Water loss (%) from meat after at 25°C and 70°C was determined. Whole genomes of Salmonella were interrogated to identify the presence/absence of stress response genes (n=30) related to dry heat which may contribute to the survival of Salmonella. The survival of Salmonella at 25°C was significantly higher across all surfaces (~6.09–7.91 log cfu/cm2) as compared to 70°C (~3.66–6.33 log cfu/cm2). On rubber, numbers of Salmonella were <LOD at 70°C. Water loss at 70°C (~17.72–19.89%) was significantly higher as compared to 25°C (~2.98–4.11%). Salmonella was not detected on rubber while survival occurred on all red meat at 70°C, suggesting its protective effect against the effect of heat. All Salmonella strains carried 30 stress response genes which likely contributed to its survival. A multi-antibiotic resistant S. Typhimurium 2470 exhibited an increase in heat resistance at 70°C on beef and lamb as compared to other strains. Our work shows that dry heat at 70°C for 1 h against Salmonella on red meat is not a practical approach for effectively reducing or eliminating them from red meat.

Assessing the Impact of Heat Treatment of Food on Antimicrobial Resistance Genes and Their Potential Uptake by Other Bacteria—A Critical Review

“…AMR strains were reported to be no more heat resistant than non-AMR strains, in relation to Salmonella in beef [ 62 ]. Though as previously reported, AMR strains of Salmonella were more heat resistant than non-AMR strains to a dry heat treatment [ 61 ].…”

“…The majority of published reviews and studies conclude that there is no evidence to suggest that AMR bacteria are more heat tolerant than non-AMR bacteria, with the exception of three studies [ 51 , 60 , 61 ].…”

“…A study on the impact of a dry heat treatment at 70 °C for up to an hour on inoculated strains of Salmonella spp. on beef, lamb, and goat meat in the context of a processing CCP intervention step also reported AMR strains to be particularly heat resistant [ 61 ]. Of the Salmonella strains used, an AMR strain of S .…”

Anti-Salmonella Activity of Thymus serpyllum Essential Oil in Sous Vide Cook–Chill Rabbit Meat

“…Currently utilized physical interventions to minimize Salmonella on red meat, notably beef, include heating to a temperature between 48 and 66 • C; nonetheless, depending on the serotype, these bacteria have been reported to survive [36][37][38]. In other research, it was found that in high-moisture foods like meat and a model meat juice system, Salmonella can survive exposure to heating at temperatures as high as 70 • C [39]. Numerous investigations have been carried out to ascertain Salmonella's heat tolerance on beef and chicken meat at either ≤70 • C or ≥70 • C [38,40,41].…”

Aplikasi Basic Local Alignment Search Tool (BLAST) NCBI Pada Penelitian Molekuler Salmonella SPP

“…Su et al (2018) melaporkan hasil BLAST menunjukkan keberadaan gen PMQR and mcr-1 pada isolat Salmonella yang berasal dari babi yang terkena diare. (Sarjit, Ravensdale, Coorey, Fegan, & Dykes, 2021). ( 2019) melaporkan hasil BLAST menunjukkan keberadaan gen yang merespon pemberian kondisi stress heatshock fadA, rpoH, rpoE, rpoD, rpoS, fkpA, cpxP, ibpA htrA, htpG, cypD, gyrA, ompC, dnaJ, dnaK, yggX, grpE, rdgB, pspA, groEL dan gen yang merespon kondisi kekeringan yaitu gen rpoS, otsB, hilA, dnaK, grpE, proV, sseD, sopD, STM1494 pada Salmonella yang berasal dari daging merah (Selçuk, 2019).…”