Hygiene Indicators and Salmonellae on Surfaces of Swine Carcasses from Two Slaughterhouses in Northern Portugal

Abstract

The monitorization of carcass surfaces contamination along the slaughter lines enables the verification of the slaughter operations hygiene and the good manufacturing practices. Pork meat is a common source of human non-typhoidal salmonellosis, one of the most frequently reported foodborne illnesses worldwide. This study aimed to gather data on microbial loads in carcass surfaces in two slaughterhouses, before and after evisceration. Salmonella enterica search was made after evisceration, due to the frequent reference to pork as being a common carrier of this microorganism. The contamination of carcass surfaces was evaluated by delimitation of surface area with sterilized templates (100 cm2), and sampled by gauze swabs. Enumeration of total aerobic mesophilic microorganisms, Enterobacteriaceae, and Escherichia coli was performed. The detection of Salmonella was performed for carcass surfaces after evisceration, and from animal liver and floor drains (environmental). Significant differences (p < 0.05) were observed for mesophilic microorganisms, Enterobacteriaceae, and E. coli counts on the external surfaces, with higher counts after evisceration. The neck and abdominal area presented higher levels for mesophilic microorganisms, Enterobacteriaceae and E. coli, and a high prevalence of Salmonella. Salmonella was detected only in one of the studied slaughterhouses; 19 out of 259 analysed carcass samples were positive for Salmonella (7.3%). Salmonella was also detected in two livers and in two floor drains. A collection of 52 Salmonella isolates (44 from carcasses, 5 from livers, 3 from drains) was gathered. Three serovars of Salmonella were identified (Typhimurium 4,5:i- , Wernigerone and Derby), and 53.8% of isolates were multidrug-resistant. The results demonstrate the need for continuous improvement of slaughtering operations and good manufacturing practices, to ensure food safety of pork produced in Portugal.

Levels of Different Microbial Groups on Inert Surfaces of Poultry Slaughterhouses: Identification Using Matrix-Assisted Laser Desorption Ionization Time-of-Flight and Detection of Extended-Spectrum Beta-Lactamase- and Carbapenemase-Producing Enterobacteria

“…(0.34%) [37], but higher as for Enterobacteriaceae in general (60%) [38], on different surfaces of slaughterhouses and retail establishments. Monitoring the presence of different genera of Enterobacteriaceae, including the ones reported in this study, along the slaughter line enables the verification of slaughter operation hygiene and the use of good manufacturing practices by slaughter operators [39].…”

The Distribution Characteristics of Aerosol Bacteria in Different Types of Pig Houses

“…Firmicutes are the most abundant phylum in the intestinal microbiome of pigs at all growth stages [ 38 ], suggesting that the dominant bacteria in the air of the pig house may originate from feces [ 39 ]. Proteobacteria is the largest phylum of bacteria, including many pathogenic bacteria, such as Escherichia coli, Salmonella, Vibrio cholera, Helicobacter pylori, and other well-known species [ 40 , 41 , 42 , 43 ], while some members of Proteobacteria play an important ecological role in various environments [ 44 ].…”

Foodborne bacteria in slaughterhouses : with focus on cleaning and disinfection

“…Bacteria are of particular concern in terms of the safety and quality of raw meat (Meat Industry Guide 2017; EFSA & ECDC 2022), as they can multiply in food under the right circumstances, unlike most other hazards. To prevent contamination of meat, a hygienic slaughter process is essential and must be followed by efficient cleaning and disinfection (C&D) procedures (EC 2004;Moura-Alves et al 2022).…”