Development of a predictive model for Salmonella spp. reduction in meat jerky product with temperature, potassium sorbate, pH, and water activity as controlling factors

A comprehensive review of drying meat products and the associated effects and changes

Preserving fresh food, such as meat, is significant in the effort of combating global food scarcity. Meat drying is a common way of preserving meat with a rich history in many cultures around the globe. In modern days, dried meat has become a well enjoyed food product in the market because of its long shelf-life, taste and health benefits. This review aims to compile information on how the types of meat, ingredients and the used drying technologies influence the characteristics of dried meat in physicochemical, microbial, biochemical and safety features along with technological future prospects in the dried meat industry. The quality of dried meat can be influenced by a variety of factors, including its production conditions and the major biochemical changes that occur throughout the drying process, which are also discussed in this review. Additionally, the sensory attributes of dried meat are also reviewed, whereby the texture of meat and the preference of the market are emphasized. There are other aspects and concerning issues that are suggested for future studies. It is well-known that reducing the water content in meat helps in preventing microbial growth, which in turn prevents the presence of harmful substances in meat. However, drying the meat can change the characteristics of the meat itself, making consumers concerned on whether dried meat is safe to be consumed on a regular basis. It is important to consider the role of microbial enzymes and microbes in the preservation of their flavor when discussing dried meats and dried meat products. The sensory, microbiological, and safety elements of dried meat are also affected by these distinctive changes, which revolve around customer preferences and health concerns, particularly how drying is efficient in eliminating/reducing hazardous bacteria from the fish. Interestingly, some studies have concentrated on increasing the efficiency of dried meat production to produce a safer range of dried meat products with less effort and time. This review compiled important information from all available online research databases. This review may help the food sector in improving the efficiency and safety of meat drying, reducing food waste, while maintaining the quality and nutritional content of dried meat.

Emerging Trends for Nonthermal Decontamination of Raw and Processed Meat: Ozonation, High-Hydrostatic Pressure and Cold Plasma

Meat may contain natural, spoilage, and pathogenic microorganisms based on the origin and characteristics of its dietary matrix. Several decontamination substances are used during or after meat processing, which include chlorine, organic acids, inorganic phosphates, benzoates, propionates, bacteriocins, or oxidizers. Unfortunately, traditional decontamination methods are often problematic because of their adverse impact on the quality of the raw carcass or processed meat. The extended shelf-life of foods is a response to the pandemic trend, whereby consumers are more likely to choose durable products that can be stored for a longer period between visits to food stores. This includes changing purchasing habits from “just in time” products “for now” to “just in case” products, a trend that will not fade away with the end of the pandemic. To address these concerns, novel carcass-decontamination technologies, such as ozone, high-pressure processing and cold atmospheric plasma, together with active and clean label ingredients, have been investigated for their potential applications in the meat industry. Processing parameters, such as exposure time and processing intensity have been evaluated for each type of matrix to achieve the maximum reduction of spoilage microorganism counts without affecting the physicochemical, organoleptic, and functional characteristics of the meat products. Furthermore, combined impact (hurdle concept) was evaluated to enhance the understanding of decontamination efficiency without undesirable changes in the meat products. Most of these technologies are beneficial as they are cost-effective, chemical-free, eco-friendly, easy to use, and can treat foods in sealed packages, preventing the product from post-process contamination. Interestingly, their synergistic combination with other hurdle approaches can help to substitute the use of chemical food preservatives, which is an aspect that is currently quite desirable in the majority of consumers. Nonetheless, some of these techniques are difficult to store, requiring a large capital investment for their installation, while a lack of certification for industrial utilization is also problematic. In addition, most of them suffer from a lack of sufficient data regarding their mode of action for inactivating microorganisms and extending shelf-life stability, necessitating a need for further research in this area.

High hydrostatic pressure combined with moisture regulators improves the tenderness and quality of beef jerky

The influence of high hydrostatic pressure (HHP) at different pressure levels (0.1, 100, 200, and 300 MPa) combined with moisture regulators (MR) on the tenderness, water content, and quality of beef jerky was investigated. HHP treatment reduced the shear force (SF) of beef jerky (P < 0.05). The beef jerky treated with MR+HHP exhibited higher tenderness than the beef jerky treated only with HHP (P < 0.05). The MR+HHP samples had significantly higher moisture content than the HHP samples (P > 0.05) when the water activity was maintained at approximately 0.7. MR+HHP contributed to a shorter T₂₁ value and a higher P₂₁ value, which indicated an improvement in the water-binding ability of the beef muscle. Analysis of the microstructure showed that MR+HHP led to the fracture of the Z-line and destruction of the sarcomere structure. Sensory analysis showed that MR+HHP-200 samples had significantly higher tenderness and overall acceptable scores than other samples (P < 0.05).

Application of ε-polylysine in extending the storage period of pork jerky

In this experiment, natural nontoxic preservative ε-polylysine (ε-PL) was used as a natural preservative in pork jerky. The pork jerky samples with ε-PL (experimental group) and without ε-PL (blank group) were stored at the 27 and 37℃. Then, the number of microorganisms, total volatile basic nitrogen (TVB-N), pH, and water activity (Aw) of each group were tested to test the antiseptic effect of ε-PL. The results showed that due to the Staphylococcus aureus was detected, the storage period of the blank group at 27 and 37°C was 15 and 9 days, respectively. However, Coliforms, Staphylococcus aureus, Salmonella, and Shigella were not detected in the experimental group on the 60th day. The experimental group all accord with the national standard for the quantity of microorganisms in meat jerky. The TVB-N content of the blank group reached 14.00 mg/100 g (15th day, 27°C) and 14.93 mg/100 g (9th day, 37°C) at the end of the storage period, while the TVB-N content of the experimental group was 11.20 mg/100 g (60th day, 27℃) and 15.86 mg/100 g (60th day, 37℃), and the increase rate of TVB-N in the blank group was greater than the experimental group, indicating that ε-PL can play a better microbial stabilization effect in pork jerky. The test of pH and Aw showed that ε-PL can stabilize the quality of pork jerky. Finally, the antiseptic effect of ε-PL was comparable to many chemical preservatives. This experiment confirms that ε-PL played an important role in extending the storage period of pork jerky.

Salmonella Prevalence Alone Is Not a Good Indicator of Poultry Food Safety

Salmonella is a leading cause of foodborne illness (i.e., salmonellosis) outbreaks, which on occasion are attributed to ground turkey. The poultry industry uses Salmonella prevalence as an indicator of food safety. However, Salmonella prevalence is only one of several factors that determine risk of salmonellosis. Consequently, a model for predicting risk of salmonellosis from individual lots of ground turkey as a function of Salmonella prevalence and other risk factors was developed. Data for Salmonella contamination (prevalence, number, and serotype) of ground turkey were collected at meal preparation. Scenario analysis was used to evaluate effects of model variables on risk of salmonellosis. Epidemiological data were used to simulate Salmonella serotype virulence in a dose-response model that was based on human outbreak and feeding trial data. Salmonella prevalence was 26% (n = 100) per 25 g of ground turkey, whereas Salmonella number ranged from 0 to 1.603 with a median of 0.185 log per 25 g. Risk of salmonellosis (total arbitrary units (AU) per lot) was affected (p ≤ 0.05) by Salmonella prevalence, number, and virulence, by incidence and extent of undercooking, and by food consumption behavior and host resistance but was not (p > 0.05) affected by serving size, serving size distribution, or total bacterial load of ground turkey when all other risk factors were held constant. When other risk factors were not held constant, Salmonella prevalence was not correlated (r = -0.39; p = 0.21) with risk of salmonellosis. Thus, Salmonella prevalence alone was not a good indicator of poultry food safety because other factors were found to alter risk of salmonellosis. In conclusion, a more holistic approach to poultry food safety, such as the process risk model developed in the present study, is needed to better protect public health from foodborne pathogens like Salmonella.

Salmonella survival after exposure to heat in a model meat juice system

The effect of heat against eleven Salmonella strains in model meat juices was examined. Juices from beef, lamb and goat were made from either the fatty layer (FL), muscle (M) or a mixture of both (FLM). The pH of each FLM sample was altered to match the pH of PBS and vice versa to determine the pH effect on the survival of Salmonella against the effect of heat. Salmonella were exposed to either gradual heating to 70 °C in FLM, M and FL or heat shock at 70 °C for 5 min in FLM. Fat, fatty acid profile and iron content of the juices were determined. Gradual heat treatment significantly (p ≤ 0.05) reduced Salmonella as compared to the untreated controls (~1.92-7.61 log CFU ml^-1) while heat shock significantly (p ≤ 0.05) reduced Salmonella as compared to the untreated controls (~5.80-7.36 log CFU ml^-1). Survival of Salmonella was higher in lamb juices than other juices. The fat content in lamb FL (3.25%) was significantly higher (p ≤ 0.05) than beef (1.30%) and goat FL (1.42%). Iron content in lamb FLM (~127 mg kg^-1) was significantly (p ≤ 0.05) lower than beef (~233 mg kg^-1) and goat FLM (~210 mg kg^-1). The omega 6 and linoleic acid content in goat FLM (~36.0% and ~34.4%) was significantly higher (p ≤ 0.05) than beef (~29.1% and ~27.1%). Fat, fatty acids and iron may differentially protect Salmonella against the effect of heat in these juices.

Comparison of predicted and impedance determined growth of Listeria innocua in complex food matrices

Indirect impedance has been used for the detection and enumeration of bacteria, however there is limited data regarding the ability of the method to measure growth and inhibition of microorganisms in food in response to preservatives. The aim of this study was to evaluate the suitability of the technique to determine maximum growth rates of Listeria innocua (used as a surrogate for Listeria monocytogenes) in complex food matrices to which multiple preservative factors had been applied and assess the suitability of the data for use in predictive microbiology. Growth of L. innocua in laboratory medium (BHI broth) and two food matrices (zucchini purée and béarnaise sauce) under varying conditions of pH (5 & 5.3), water activity (0.93, 0.96 & 0.98) and acetic and propionic acid concentration (0, 1 & 2 mM) was monitored by the conductimetric Rapid Automated Bacterial Impedance Technology (R.A.B.I.T) system by means of CO₂ emission for up to 120 h. Growth rates of L. innocua were determined for several conditions across the three test matrices and a good correlation between detection times and initial inoculum level was observed in most cases (R² ≥ 0.82). However, growth of L. innocua was not detected in a large number of conditions and comparison of growth rates determined by indirect impedance to those determined by plate counts indicated that in general, the R.A.B.I.T. system under-estimated growth. This study demonstrates that there are limitations associated with the technology, and as a result the system may be unsuitable for measuring microbial growth rates in complex food matrices under the environmental conditions tested and within the time duration of the study.