Identification of priority bacterial groups to optimize sanitary procedures at meat processing plants

The meat industry continues to play an important role in the growth and maintain in food chains of human diets and nutrients to our society. To fully understand the implication of improvements and problems in animal products impacts to the meat quality and safety during the processing, this book aimed to bring comprehensive recent advances for better understanding of meat quality and safety as well as nutrient factors and recovery of values from by- products. The chapters 1 and 2 summarized the live stock hygiene control and Hazard Analysis and Critical Control Points (HAACP) system in the meat production and practices. The sources of microbial contamination in meats from livestock and processing plant are highlighted and improvement of meat safety by HAACP program is described well. In Chapter 2, various chemical and physical methods of decontamination of meat are summarized. The effect of probiotics and prebiotics in cooked meat products is highlighted, and its mechanism and beneficial effects were described in chapter 3. Tenderness, juiciness, taste and flavour of meats are the most important factors for meat consumers. The chapter 4 did deal with important factors affecting meat tenderization and chemical and physical methods of meat tenderization, which improve meat quality. Nano-technology in food processing is getting important and promising technology to improve texture, flavour and add more values. This technology is also useful for applying to food safety, bio safety, packaging and so on. The current trend of nano-technology in meat processing is highlighted in Chapter 5 and this covers many aspects of food nano-technology, bio sensing of meat, meat packaging, and pathogen identification in muscle foods. Irradiation in foods is always arguments on its efficacy and safety issues. Radiation processing technology of meats and quality changes by this processing are summarized in Chapter 6 including safety and nutrient changes of irradiation in meat products. The comminuted meat products are unique type of processed meat products made by mechanical process of reducing raw materials to small particles. Types of comminuted meat products, processing steps, meat and non-mat ingredients and quality of comminutd products are very well dealt with in chapter 7. Chapter 8 describes the current meat products and processing technologies of various commercial meat products, such as sausages, enrobed meat products, intermediate moisture meat foods, restructured meat products, meat analogues and designer meat products. Technological and microbiological aspects of fermented sausages, new information obtained by using modern approaches to study the microbial ecology based on molecular biology methods are focused in chapter 9. Thermal processing of meat inactivates pathogens and spoilage organisms to produce shelf stable products. Principles of thermal processing including canning, retort pouch processing, microwave cooking, extrusion cooking and ohmic heating are briefly discussed in chapter 10. These chapters help reader to understand various meat products and technologies behind these products including nutrient issues and functionality changes. Lastly, the waste management of meat by-products and recovery of biomaterials from animal wasters are discussed in Chapter 11. Over 50% of live animal weight is considered as by- products and recovery of valuable components is critical in future meat industry and minimizing the environments pollution by their disposal. This chapter addresses this challenge and future perspective for readers. This book is well organized and contains much comprehensive information in current practices of meat industry and muscle foods. It is recommended for use as a textbook for animal, food and nutrition graduate program. It is also useful for livestock and meat industry people as well as nutraceutical personnel as a handbook.

Several species of the genus Acinetobacter are nosocomial pathogens with a well-documented ability to acquire resistance to multiple antibiotics. Although Acinetobacter is one of the most abundant genera in meat processing environments, data on this genus outside of clinical environments remains limited. The objective of this study was to ascertain the prevalence, diversity and antimicrobial resistance profile of Acinetobacter spp. in 200 samples collected from food contact surfaces, non-food contact surfaces, carcasses and final meat cuts across five pork, chicken and beef processing facilities, each comprising physically connected slaughterhouses and meat processing plants. Acinetobacter spp. were detected in 80% (95% CI = 71–87%) and 70% (95% CI = 60–79%) of samples from slaughterhouses and processing plants, respectively. The facilities harboured a wide diversity of Acinetobacter species, with 27 different species identified. Acinetobacter baumannii was the species most frequently detected. Whole-genome sequencing of 18 Acinetobacter spp. isolates revealed the presence of ARGs conferring resistance to beta-lactams, tetracyclines and aminoglycosides, and disclosed phylogenetic relationships with isolates from fresh meat. Phenotypic resistance to beta-lactams, fluoroquinolones, aminoglycosides, folate pathway inhibitors and/or tetracyclines was observed in 77.8% of the sequenced isolates, with 44.4% classified as multidrug-resistant. These findings identify meat processing environments as an important reservoir of Acinetobacter spp. and highlight the need for further investigation to prevent the dissemination of antimicrobial-resistant strains.

MLVA subtyping of Listeria monocytogenes isolates from meat products and meat processing plants

Different strains of Listeria monocytogenes are well known to persist in individual food processing plants and to contaminate foods for many years; however, the specific genotypic and phenotypic mechanisms responsible for persistence of these unique strains remain largely unknown. Based on sequences in comK prophage junction fragments, different strains of epidemic clones (ECs), which included ECII, ECIII, and ECV, were identified and shown to be specific to individual meat and poultry processing plants. The comK prophage-containing strains showed significantly higher cell densities after incubation at 30°C for 48 h on meat and poultry food-conditioning films than did strains lacking the comK prophage (P < 0.05). Overall, the type of strain, the type of conditioning film, and the interaction between the two were all highly significant (P < 0.001). Recombination analysis indicated that the comK prophage junction fragments in these strains had evolved due to extensive recombination. Based on the results of the present study, we propose a novel model in which the concept of defective comK prophage was replaced with the rapid adaptation island (RAI). Genes within the RAI were recharacterized as "adaptons," as these genes may allow L. monocytogenes to rapidly adapt to different food processing facilities and foods. If confirmed, the model presented would help explain Listeria's rapid niche adaptation, biofilm formation, persistence, and subsequent transmission to foods. Also, comK prophage junction fragment sequences may permit accurate tracking of persistent strains back to and within individual food processing operations and thus allow the design of more effective intervention strategies to reduce contamination and enhance food safety.

We examined the rates of pathogenic bacterial cross-contamination from gloves tomeat and from meat to gloves during pork processing under meat-handlingscenarios in transfer rate experiments of inoculated pathogens. The inoculatedpork contained ~5–6 Log10 CFU/g pathogenic bacteria likeEscherichia coli (E. coli),Staphylococcus aureus (S. aureus),Listeria monocytogenes (L. monocytogenes),and Salmonella enterica subsp. enterica(Sal. enteritidis). On cotton gloves, after cutting thepork, the cutting board, knife, and cotton gloves showed 3.07–3.50,3.29–3.92 and 4.48–4.86 Log10 CFU/g bacteria. However,when using polyethylene gloves, fewer bacteria (3.12–3.75,3.20–3.33, and 3.07–3.97 Log10 CFU/g, respectively)were transferred. When four pathogens (6 Log10 CFU/g) were inoculatedonto the gloves, polyethylene gloves showed a lower transition rate (cuttingboard 2.47–3.40, knife 2.01–3.98, and polyethylene glove2.40–2.98 Log10 CFU/g) than cotton gloves. For cotton gloves,these values were 3.46–3.96, 3.37–4.06, and 3.55–4.00Log10 CFU/g, respectively. Use of cotton gloves, polyethylenegloves, knives and cutting boards for up to 10 hours in a meat butcheringenvironment has not exceeded HACCP regulations. However, after 10 h of use,3.09, 3.27, and 2.94 Log10 CFU/g of plate count bacteria weredetected on the cotton gloves, cutting board, and knives but polyethylene glovesshowed no bacterial count. Our results reveal the transfer efficiency ofpathogenic bacteria and that gloved hands may act as a transfer route ofpathogenic bacteria between meat and hands. The best hand hygiene was achievedwhen wearing polyethylene gloves. Thus, use of polyethylene rather than cottongloves reduces cross-contamination during meat processing.

Tracking and tracing system is an important technology to guarantee food product safety. A design and realization of intelligent food production processing monitoring system for pork production processing is introduced. Production data in the processing of the system is studied. Using radial base function (RBF) neural network, fuzzy data processing techniques, the system analyze over-range abnormality data, and tracing data of pork processing supply chain control is standardized through European article numbering-uniform code council (EAN/UCC) system. Then quality information exchange of pork production and processing of each member of supply chain is achieved. Therefore, product quality monitoring pre-warning and traceability in the process of food processing is realized. The system real-timely monitors, acquires and exchanges pork producing and processing data by using Radio Frequency Identification (RFID) , Controller Area Network (CAN) bus and embedded system technologies. Through constructing software and hardware platforms, the real-time data are imploded into data link of tracing information which ensures the data consistency and integrity. Thus, tracing and tracking the whole pork slaughter and processing information are effectively implemented. System operation showed that the proposed intelligent monitoring system had good real-time performance, high reliability and accuracy.

In this study, we used both a WGS and an in vitro approach to study the virulence potential of nine Listeria monocytogenes (Lm) strains belonging to genetic clusters persisting in a meat processing plant in Central Italy. The studied clusters belonged to CC1-ST1, CC9-ST9, and CC218-ST2801. All the CC1 and CC218 strains presented the same accessory virulence genes (LIPI-3, gltA, gltB, and aut_IVb). CC1 and CC9 strains presented a gene profile similarity of 22.6% as well as CC9 and CC218 isolates. CC1 and CC218 showed a similarity of 45.2% of the same virulence profile. The hypervirulent strains of lineage I (CC1 and CC218) presented a greater ability to adhere and invade Caco-2 cells than hypovirulent ones (CC9). CC1 strains were significantly more adhesive and invasive compared with CC9 and CC218 strains, although these last CCs presented the same accessory virulence genes. No statistically significant difference was found comparing CC218 with CC9 strains. This study provided for the first time data on the in vitro adhesiveness and invasiveness of CC218-ST2801 and added more data on the virulence characteristics of CC1 and CC9. What we observed confirmed that the ability of Lm to adhere to and invade human cells in vitro is not always decipherable from its virulence gene profile.

Incidence and principal sources of Listeria spp. and Listeria monocytogenes contamination in processed meats and a meat processing plant

The zoonotic Listeria monocytogenes is mainly transmitted to humans by the food-borne route. This bacterium was often found in the environment of food processing plants. Therefore the aims of this study were (i) the identification of environmental factors associated with L. monocytogenes contamination on working and non-working surfaces in poultry or pork processing plants and (ii) the understanding of its survival in such environments. The physicochemical risk profiles showed that a surface in resin or plastic, rather than uneven, with organic residues, with a neutral pH, a low temperature and a high hygrometry was associated with L. monocytogenes contamination.

Edible films can be used as wrapping material on food products to reduce surface contamination. The incorporation of antimicrobials into edible films could serve as an additional barrier against pathogenic and spoilage microorganisms that contaminate food surfaces. The objective of this study was to investigate the antimicrobial effects of carvacrol and cinnamaldehyde, incorporated into apple, carrot, and hibiscus-based edible films against Listeria monocytogenes on contaminated ham and bologna. Ham or bologna samples were inoculated with L. monocytogenes and dried for 30 min, then surface wrapped with edible films containing the antimicrobials at various concentrations. The inoculated, film-wrapped samples were stored at 4 °C. Samples were taken at day 0, 3, and 7 for enumeration of surviving L. monocytogenes by plating on appropriate media. Carvacrol films showed better antimicrobial activity than cinnamaldehyde films. Compared to control films without antimicrobials, films with 3% carvacrol induced 1 to 3, 2 to 3, and 2 to 3 log CFU/g reductions on ham and bologna at day 0, 3, and 7, respectively. Corresponding reductions with 1.5% carvacrol were 0.5 to 1, 1 to 1.5, and 1 to 2 logs, respectively. At day 7, films with 3% cinnamaldehyde reduced L. monocytogenes population by 0.5 to 1.5 and 0.5 to 1.0 logs on ham and bologna, respectively. Inactivation by apple films was greater than that by carrot or hibiscus films. Apple films containing 3% carvacrol reduced L. monocytogenes population on ham by 3 logs CFU/g on day 0 which was 1 to 2 logs greater than that by carrot and hibiscus films. Films were more effective on ham than on bologna. The food industry and consumers could use these films to control surface contamination by pathogenic microorganisms. Antimicrobial edible, food-compatible film wraps prepared from apples, carrots, and hibiscus calyces can be used by the food industry to inactivate Listeria monocytogenes on widely consumed ready to eat meat products such as bologna and ham. This study provides a scientific basis for large-scale application of edible fruit- and vegetable-based antimicrobial films on foods to improve microbial food safety.

Organic acids are vital in the production of shrimp and fish pastes, influencing fermentation, preservation, flavor, and safety. These acids, primarily lactic, acetic, and propionic, are produced during fermentation facilitated by lactic acid bacteria. They enhance sensory qualities and extend shelf life by inhibiting spoilage and pathogenic microorganisms through pH reduction. However, their concentrations must comply with regulatory standards to ensure consumer safety and mitigate health risks. The integration of organic acids into seafood pastes not only supports preservation but also improves flavor complexity. Lactic acid provides tanginess, acetic acid adds a sharp, vinegar-like flavor, and propionic acid aids in microbial stability without altering taste. The combination of these acids enhances the texture, aroma, and overall sensory profile of the products. Adherence to permissible limits is critical, as excessive concentrations may pose metabolic risks. Regulatory bodies like the FDA and EFSA establish guidelines to ensure these acids are safely used within acceptable daily intake levels. Innovations in fermentation technology, including the use of starter cultures and controlled environments, offer opportunities for better management of organic acid production, improving product quality and consistency. Emerging non-thermal preservation methods, such as high-pressure processing, further ensure safety without compromising the natural characteristics of seafood pastes. Continued research into organic acid dynamics and alternative preservation techniques is essential to meet consumer demands for safe, high-quality, and naturally fermented seafood products, while maintaining compliance with global food safety standards.

(1) Background: L. monocytogenes is a food pathogen of great importance, characterized by a high mortality rate. Quaternary ammonium compounds (QACs), such as benzalkonium chloride (BC), are often used as disinfectants in food processing facilities. The effectiveness of disinfection procedures is crucial to food safety. (2) Methods: A collection of 153 isolates of L. monocytogenes from meat processing industry was analyzed for their sensitivity to BC using the agar diffusion method. Genes of interest were detected with PCR. (3) Results: Genes emrC, bcrABC, and qacH were found in 64 (41.8%), 6 (3.9%), and 1 isolate (0.7%), respectively, and 79 isolates (51.6%) were classified as having reduced sensitivity to BC. A strong correlation between carrying QACs resistance-related genes and phenotype was found (p-value < 0.0001). Among 51 isolates originating from bacon (collected over 13 months), 48 had the emrC gene, which could explain their persistent presence in a processing facility. Isolates with the ilsA gene (from LIPI-3) were significantly (p-value 0.006) less likely to carry QACs resistance-related genes. (4) Conclusions: Reduced sensitivity to QACs is common among L. monocytogenes from the meat processing industry. Persistent presence of these bacteria in a processing facility is presumably caused by emrC-induced QACs resistance.

Pulsed electric field processing of different fruit juices: Impact of pH and temperature on inactivation of spoilage and pathogenic micro-organisms

Distribution of airborne microorganisms in commercial pork slaughter processes

Rhamnolipid and surfactin: Anti-adhesion/antibiofilm and antimicrobial effects