Study of the effect of probiotics on the shelf life of chilled broiler meat

The food industry is always looking for new ways to extend the shelf life of fresh meat products while maintaining their microbial and sensory quality. Microbiological safety and poultry meat quality are equally important to producers, retailers, and consumers, and both involve microbial contaminants on the processed product. To some extent analogous to traditional poultry production, various factors can affect alternative production methods, and the addition of a suitable probiotic may enhance efficacy, decrease morbidity and mortality, diminish environmental contamination, and augment food safety. Probiotics, defined as live microorganisms that can provide a health benefit to the host when consumed in suffi- cient amounts, have been shown in various studies to improve animal health and performance [1].

This research aims to look into the effect of probiotics on the shelf life of chilled broiler meat. In this study, the probiotics under investigation were sourced from koumiss and shubat, which are fermented drinks derived from mare's and camel's milk, respectively.

Shori (2017) [2] suggests that raw camel milk and its fermented products are potential sources of beneficial probiotic strains. Furthermore, camel milk and the microorganisms present in shubat are essential contributors to the sensory attributes, such as flavor, texture, and acidity, of these beverages. They also have therapeutic effects on digestion and antimicrobial properties [3].

Koumiss, a fermented drink derived from mare's milk, has been recognized as a potential source of probiotics. During the fermentation of koumiss, several microorganisms such as lactic acid bacteria, yeast, and acetic acid bacteria actively participate, thereby enhancing the microbial diversity and conferring health-promoting effects to the beverage. The presence of probiotic microorganisms, including Lactobacillus and Bifidobacterium species, has been identified in koumiss through scientific investigations, and these microorganisms have been shown to confer beneficial effects on the host's health [4].

The specific goals of this study are to determine the microbial quality of the meat samples, including QMAFAnM, BGKP, pathogenic ( Salmonella, Listeria monocytogenes ), yeast, and mold, as well as to evaluate the sensory parameters to determine the shelf life of the meat samples.

The study's hypothesis is that using probiotics in broiler feed will increase the shelf life and microbial quality of fresh broiler meat. The study will take a quantitative approach, with experimental design and statistical data analysis.

This study is significant because it adds to our understanding of the potential benefits of probiotics in fresh broiler meat in Kazakhstan. The findings of this study can help the food industry improve the shelf life and microbial quality of fresh meat products, as well as increase the nutritional value of animal feed.

Materials and Research Methods

Materials . Lacticaseibacillus paracasei B 5.2, Lacticaseibacillus paracasei subsp. paracasei SH1 (GenBank Accession No. OQ411023), Lac-tiplantibacillus plantarum K2 and Kazachstania unispora Y 2.2 (Genbank Accession No. OP984721) were used in this study as the potential probiotics microorganisms. The strains were obtained from the culture bank of LLP Research and Production Enterprise "Antigen" (Almaty, Kazakhstan) which was stored at -80ºC.

A total of 240 one-day-old Ross 308 chicks were randomly allotted to four treatment groups of 3 replicates (20 birds per replicate). For the control group, birds were fed by basal diet and drinking water (DW). Chicks in the experimental groups were fed by BD, DW, and probiotics 0.25 mL, 0.5 mL, and 1.0 mL per bird (groups Pro1, Pro2, and Pro3, respectively), for 42 days.

For sensory and microbiological evaluations after slaughter, 40 samples were randomly obtained and analyzed. These samples consisted of 10 filets from each group: 1 - control group, 2 -Pro1 experimental group, 3 - Pro2 experimental group, and 4 - Pro3 experimental group.

Methods. Microbiological analysis . According to the Health Regulations «Sanitary and epidemiological requirements for food production facilities» (dated April 28, 2021, No. KR DSM-36), broiler chicken carcasses must undergo at least three sanitary and microbiological control points during both control and experimental batches. The first control point occurs immediately after production and serves as a background check. The second and third control points occur on the second and third days. Subsequent control points are conducted every two days until the microbial indicators meet the requirements of the sanitary rules.

Of the standard microbiological methods available for analyzing food products, the following will be applicable:

• - State Standard 10444.15-94. Food products. Methods for determination of the quantity of mesophilic aerobes and facultative anaerobes;

• - State Standard 52816 -2007. Food products. Methods for detection and quantity determination of coliforms;

• - State Standard 30726-2001. Food-stuffs. Methods for detection and determination of Escherichia coli;

• - State Standard 52814-2007 (ISO 6579:2002). Food products. Method for the detection of Salmonella;

• - State Standard 29185 -91. Food products. Methods for detection and quantity determination of sulfite-reducing clostridium;

• - State Standard 51921 – 2002. Food products. Methods for detection and determination of Listeria monocytogenes bacteria;

• - State Standard 10444.12-88. Food products. Method for determination of yeast and mold.

Sensory Investigation . A trained sensory group evaluated the sensory investigations 24 hours and 192 hours after slaughter using a three-point rating system, with 3 indicating freshness and high quality and 1 indicating unacceptability. Color, odor, and texture were among the characteristics assessed for each sample. The sensory index (SI) was computed as a weighted average value using the following equation (1):

2хО-2хС+Т

St =-----                                        (1)

where SI is Sensory Index, O is odor, C is color and T is texture.

According to the scheme, the product degrades when SI reaches 1.8. SI was built as a time series and fitted to a linear model. As a result, the shelf life of each sample was calculated as follows using Equation 2:

SL=

where SL is shelf life, a is the intercept of the linear model, and b is the slope of the linear model.

Samples exhibiting an atypical spoilage process (no degradation in color or texture) were not included in the statistical analyses of sensory characteristics. Outliers were defined as samples with a shelf life of fewer than 100 hours and greater than 300 hours, and they were removed from the data set [5].