Growth inhibition of lactic acid bacteria in ham by nisin: A model approach

Alternative Additives for Organic and Natural Ready-to-Eat Meats to Control Spoilage and Maintain Shelf Life: Current Perspectives in the United States

Food additives are employed in the food industry to enhance the color, smell, and taste of foods, increase nutritional value, boost processing efficiency, and extend shelf life. Consumers are beginning to prioritize food ingredients that they perceive as supporting a healthy lifestyle, emphasizing ingredients they deem acceptable as alternative or "clean-label" ingredients. Ready-to-eat (RTE) meat products can be contaminated with pathogens and spoilage microorganisms after the cooking step, contributing to food spoilage losses and increasing the risk to consumers for foodborne illnesses. More recently, consumers have advocated for no artificial additives or preservatives, which has led to a search for antimicrobials that meet these demands but do not lessen the safety or quality of RTE meats. Lactates and diacetates are used almost universally to extend the shelf life of RTE meats by reducing spoilage organisms and preventing the outgrowth of the foodborne pathogen Listeria monocytogenes. These antimicrobials applied to RTE meats tend to be broad-spectrum in their activities, thus affecting overall microbial ecology. It is to the food processing industry's advantage to target spoilage organisms and pathogens specifically.

Nisin and Organic Acid Salts Improved the Microbial Quality, Extended the Shelf Life, and Maintained the Sensory Attributes of Semidry Beef Luncheon Marketed at Adverse (35-40 °C) Ambient Summer Temperatures

Semidry beef luncheon may undergo deteriorative changes during storage at ambient temperatures in tropical and subtropical regions including Egypt. This study was conducted in a meat plant in Egypt with the aim of overcoming the economic losses from the returns of spoiled unsold beef luncheon displayed in grocery stores at adverse summer temperatures of 37 °C or more. Ten approaches were applied using different preservatives, comprising sodium nitrite, nisin, potassium sorbate, and organic acid salts (a combination of sodium lactate, sodium acetate, and sodium diacetate). In addition, the product was cooked at different temperatures and was stored for 21 days at 37 °C, during which time the shelf life, microbial quality, pH, and sensory attributes were investigated. By Day 21 of storage, the luncheon contained 50 mg/kg sodium nitrite, 25 mg/kg nisin, and 1000 mg/kg organic acid salts and, when cooked at a final core temperature of 92 °C, exhibited reductions in aerobic plate count, anaerobic plate count, lactic acid bacterial count, and mold and yeast counts by 4.32, 3.54, 3.47, and 1.89 log10 CFU/g, respectively, when compared with the control. The sensory attributes and pH were also maintained in the final products of such treatment, with no product return and the avoidance of economic loss. This study presents a novel approach for solving the major problem of the deteriorative changes that occur in semidry luncheon sausage and similar meat products which require rejection with a huge economic loss, especially in tropical and semitropical areas of the world that have similar problems of high climatic temperatures and a low availability of energy or technological resources.

A Comprehensive Review of Bioactive Compounds from Lactic Acid Bacteria: Potential Functions as Functional Food in Dietetics and the Food Industry

Lactic acid bacteria (LAB) are beneficial microbes known for their health-promoting properties. LAB are well known for their ability to produce substantial amounts of bioactive compounds during fermentation. Peptides, exopolysaccharides (EPS), bacteriocins, some amylase, protease, lipase enzymes, and lactic acid are the most important bioactive compounds generated by LAB activity during fermentation. Additionally, the product produced by LAB is dependent on the type of fermentation used. LAB derived from the genera Lactobacillus and Enterococcus are the most popular probiotics at present. Consuming fermented foods has been previously connected to a number of health-promoting benefits such as antibacterial activity and immune system modulation. Furthermore, functional food implementations lead to the application of LAB in therapeutic nutrition such as prebiotic, immunomodulatory, antioxidant, anti-tumor, blood glucose lowering actions. Understanding the characteristics of LAB in diverse sources and its potential as a functional food is crucial for therapeutic applications. This review presents an overview of functional food knowledge regarding interactions between LAB isolated from dairy products (dairy LAB) and fermented foods, as well as the prospect of functioning LAB in human health. Finally, the health advantages of LAB bioactive compounds are emphasized.

A review of potential antibacterial activities of nisin against Listeria monocytogenes: the combined use of nisin shows more advantages than single use

Listeria monocytogenes is a foodborne pathogen causing serious public health problems. Nisin is a natural antimicrobial agent produced by Lactococcus lactis and widely used in the food industry. However, the anti-L. monocytogenes efficiency of nisin might be decreased due to natural or acquired resistance of L. monocytogenes to nisin, or complexity of the food environment. The limitation of nisin as a bacteriostatic agent in food could be improved using a combination of methods. In this review, the physiochemical characteristics, species, bioengineered mutants, and antimicrobial mechanism of nisin are reviewed. Strategies of nisin combined with other antibacterial methods, including physical, chemical, and natural substances, and nanotechnology to enhance antibacterial effect are highlighted and discussed. Additionally, the antibacterial efficiency of nisin applied in real meat, dairy, and aquatic products is evaluated and analyzed. Among the various binding treatments, the combination with natural substances is more effective than the combination with physical and chemical methods. However, the combination of nisin and nanotechnology has more potential in terms of the impact on food quality.

Natural Antimicrobials: A Clean Label Strategy to Improve the Shelf Life and Safety of Reformulated Meat Products

Meat is a nutrient-rich matrix for human consumption. However, it is also a suitable environment for the proliferation of both spoilage and pathogenic microorganisms. The growing demand to develop healthy and nutritious meat products with low fat, low salt and reduced additives and achieving sanitary qualities has led to the replacement of the use of synthetic preservatives with natural-origin compounds. However, the reformulation process that reduces the content of several important ingredients (salt, curing salts, etc.), which inhibit the growth of multiple microorganisms, greatly compromises the stability and safety of meat products, thus posing a great risk to consumer health. To avoid this potential growth of spoiling and/or pathogenic microorganisms, numerous molecules, including organic acids and their salts; plant-derived compounds, such as extracts or essential oils; bacteriocins; and edible coatings are being investigated for their antimicrobial activity. This review presents some important compounds that have great potential to be used as natural antimicrobials in reformulated meat products.

Phytic Acid against Clostridium perfringens Type A: A Food Matrix Study

This study evaluated the inhibitory effect of phytic acid (PA) on the spore germination and vegetative cells growth of Clostridium perfringens type A, as well as its effect in combination with maltodextrin (MD) in cooked sausages. The addition of 1% PA showed a satisfactory inhibition of spores’ germination and vegetative cells growth of C. perfringens in BHI media. The inhibitory effect of 1% PA on vegetative cells was similar to the additive sodium sorbate (SS) at 10%. Subsequently, a mixture of PA-MD (1:1; w/w) was evaluated for the inhibition of C. perfringens spores in cooked sausages. The PA-MD 1.5% and 2.5% had a similar performance to SS 10% and a similar or higher performance than 0.015% NO₂ (p < 0.05). In an unprecedented way, the present study demonstrated that PA inhibited spore germination and vegetative cells growth of C. perfringens, highlighting its potential use as an alternative and natural preservative for the meat industry.

Quality Changes and Shelf-Life Prediction of Cooked Cured Ham Stored at Different Temperatures

ABSTRACT

Cooked cured ham is a ready-to-eat food that is popular among consumers. Stored temperature has a key effect on the quality and shelf life of ham. In this work, the quality changes and shelf-life prediction of cooked cured ham stored at different temperatures were investigated. Sensory evaluation, physical and chemical indicators, and aerobic plate count were determined. Results showed that high storage temperature of cooked ham accelerates quality deterioration. Partial least squares (PLS) regression analysis based on the variable importance for projection identified nine important variables for predicting the shelf life of cooked cured ham. Compared with either PLS or back-propagation artificial neural network, the hybrid PLS-back-propagation artificial neural network model better predicts the shelf life of cooked cured ham by using the nine variables. This study provides a theoretical basis and data support for the quality control of cooked cured ham and a new idea for research on the shelf-life prediction of cooked cured ham.

HIGHLIGHTS

Metabolism Characteristics of Lactic Acid Bacteria and the Expanding Applications in Food Industry

Lactic acid bacteria are a kind of microorganisms that can ferment carbohydrates to produce lactic acid, and are currently widely used in the fermented food industry. In recent years, with the excellent role of lactic acid bacteria in the food industry and probiotic functions, their microbial metabolic characteristics have also attracted more attention. Lactic acid bacteria can decompose macromolecular substances in food, including degradation of indigestible polysaccharides and transformation of undesirable flavor substances. Meanwhile, they can also produce a variety of products including short-chain fatty acids, amines, bacteriocins, vitamins and exopolysaccharides during metabolism. Based on the above-mentioned metabolic characteristics, lactic acid bacteria have shown a variety of expanded applications in the food industry. On the one hand, they are used to improve the flavor of fermented foods, increase the nutrition of foods, reduce harmful substances, increase shelf life, and so on. On the other hand, they can be used as probiotics to promote health in the body. This article reviews and prospects the important metabolites in the expanded application of lactic acid bacteria from the perspective of bioengineering and biotechnology.

Inhibition of a spoilage exopolysaccharide producer by bioprotective extracts from Lactobacillus acidophilus CRL641 and Latilactobacillus curvatus CRL705 in vacuum-packaged refrigerated meat discs

The effect of bioprotective extracts (BEs) from Lactobacillus acidophilus CRL641 (BE-1) and Latilactobacillus curvatus CRL705 (BE-2) against the exopolysaccharide producer Latilactobacillus sakei CRL1407 in vacuum-packaged meat discs at 4 °C was evaluated. Lat. sakei CRL1407 was able to grow in control samples from 2.80 to 7.77 log CFU/g after 38 days. BE-1 and BE-2 reduced bacterial growth by 2.11 and 1.35 log CFU/g, respectively, but their combination led to a greater growth reduction (3.31 log CFU/g). The antimicrobial activity was detected in treated samples with BE-1 and BE-1 + BE-2 until day 16, while with BE-2 only at the initial time. The pH values remained constant in the discs treated with the BEs combination, whereas the greatest drop in pH was observed in control samples. The minor lipid oxidation without perceptible color changes was detected in the presence of BE-1 and BE-1 + BE-2. The combination of BEs as biocontrol agent plus conventional preservation barriers could extend the fresh meat shelf-life without quality loss.

Dried Biomass of Arthrospira platensis Inhibits Growth of Aureobasidium pullulans LW14 and Some Bacteria When Added to Unpasteurised Apple Juice

The main goal was to evaluate if dried cyanobacterium (Arthrospira platensis) biomass added to unpasteurised apple juice could inhibit growth of fungi dominant in apples and which fraction of cyanobacterium biomass contributed to this phenomenon. A. platensis biomass, its protein and/or polysaccharide fraction were added to the sterilised apple juice inoculated with Aureobasidium pullulans LW14 and stored at 4 °C for 96 h. Samples were tested against number of fungi and selected physical-chemical parameters. In the last research stage, protein fraction was added to the unpasteurised apple juice inoculated with A. pullulans LW14 to test its potency against fungi, lactic acid bacteria and acetic acid bacteria. When A. platensis biomass was added to the sterilised apple juice (1.15% w/v), it effectively inhibited growth of A. pullulans LW14 and the metabolism of all analysed sugars (glucose, sucrose and fructose). Protein fraction added to the sterilised apple juice contributed significantly to mycostatic properties of A. platensis. When protein fraction was added to unpasteurised apple juice, the same conclusions were obtained, however, except for inhibiting growth of A. platensis LW14, it inhibited growth of some bacteria.

Spoilage of Chilled Fresh Meat Products during Storage: A Quantitative Analysis of Literature Data

A literature search was performed on spoilage of fresh meat products by combining keyword query, text mining and expert elicitation. From the 258 collected studies, a quantitative analysis was first performed to identify the methods which are the most used to evaluate spoilage beside the preservation strategies suggested. In a second step focusing on a subset of 24 publications providing quantitative data on spoilage occurrence time, associations between spoilage occurrence time of meat products and specific spoilage indicators were investigated. The analysis especially focused on factors well represented in the 24 publications, i.e., gas packaging (O2 and CO2) and storage temperature. Relationships between spoilage occurrence and several microbiological indicators were also sought. The results point out possible advantages of removing dioxygen in packaging to delay spoilage occurrence, whereas, in the presence of dioxygen, the carbon dioxide proportion in the gas mixtures was shown to influence spoilage occurrence. The collected data clearly reveal a potentially protective role of lactic acid bacteria. Besides, while a spoilage role could be attributed to Pseudomonas spp., the growth of mesophilic aerobic microbes, Brochothrix spp. and Enterobacteriaceae seemed independent of spoilage occurrence time.

Preservation of Meat Products with Bacteriocins Produced by Lactic Acid Bacteria Isolated from Meat

Bacteriocins are ribosomal-synthesized antimicrobial peptides that inhibit the growing of pathogenic and/or deteriorating bacteria. The most studied bacteriocin-producing microorganisms are lactic acid bacteria (LAB), as they have great potential application in food biopreservation, since the majority have GRAS (Generally Recognized as Safe) status. The LAB-producing bacteriocins and/or bacteriocins produced by these bacteria have been widely studied, with the emphasis on those derived from milk and dairy products. On the other hand, isolates from meat and meat products are less studied. The objective of this review is to address the main characteristics, classification, and mechanism of action of bacteriocins and their use in food, to highlight studies on the isolation of LAB with bacteriocinogenic potential from meat and meat products and also to characterize, purify, and apply these bacteriocins in meat products. In summary, most of the microorganisms studied areLactococcus,Enterococcus,Pediococcus, andLactobacillus, which produce bacteriocins such as nisin, enterocin, pediocin, pentocin, and sakacin, many with the potential for use in food biopreservation.

Bacteriocinogenic LAB Strains for Fermented Meat Preservation: Perspectives, Challenges, and Limitations

Over the last decades, much research has focused on lactic acid bacteria (LAB) bacteriocins because of their potential as biopreservatives and their action against the growth of spoilage microbes. Meat and fermented meat products are prone to microbial contamination, causing health risks, as well as economic losses in the meat industry. The use of bacteriocin-producing LAB starter or protective cultures is suitable for fermented meats. However, although bacteriocins can be produced during meat processing, their levels are usually much lower than those achieved during in vitro fermentations under optimal environmental conditions. Thus, the direct addition of a bacteriocin food additive would be desirable. Moreover, safety and technological characteristics of the bacteriocinogenic LAB must be considered before their widespread applications. This review describes the perspectives and challenges toward the complete disclosure of new bacteriocins as effective preservatives in the production of safe and "healthy" fermented meat products.

Bacteriocins from lactic acid bacteria and their applications in meat and meat products

Meat and meat products have always been an important part of human diet, and contain valuable nutrients for growth and health. Nevertheless, they are perishable and susceptible to microbial contamination, leading to an increased health risk for consumers as well as to the economic loss in meat industry. The utilization of bacteriocins produced by lactic acid bacteria (LAB) as a natural preservative has received a considerable attention. Inoculation of bacteriocin-producing LAB cell as starter or protective cultures is suitable for fermented meats, whilst the direct addition of bacteriocin as food additive is more preferable when live cells of LAB could not produce bacteriocin in the real meat system. The incorporation of bacteriocins in packaging is another way to improve meat safety to avoid direct addition of bacteriocin to meat. Utilization of bacteriocins can effectively contribute to food safety, especially when integrated into hurdle concepts. In this review, LAB bacteriocins and their applications in meat and meat products are revisited. The molecular structure and characteristics of bacteriocins recently discovered, as well as exemplary properties are also discussed.