الفهرس 
REVIEW OF LITERATUREOnly 14 pages are availabe for public view
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Abstract
SUMMARY
This study included three main parts according to the proposed research plan for the study:
Part I: Survey study on some commercial meat products.
Part II: Processing of Beef luncheon at laboratory scale.
Part III: Suggestion of HACCP plan for Beef luncheon production.
Part I: Survey study on some commercial meat products.
The microbiological quality and safety of 7 commercial meat products (Beef burger, kofta, souse, sausage, minced meat, pastrami, beef luncheon) distributed in the Egyptian market were analyzed.
1.1 Microbiological quality of some commercial meat products.
Total bacterial counts, lactic acid bacteria, coliforms, Staphylococcus, yeasts & molds were determined in the 7 collected commercial meat products and compared with the standard limits of the Egyptian Organization for Standardization and Quality (EOSQ, 2005). The obtained results showed high microbial loads surpassing safety limits stipulated by the Egyptian Organization for Standardization and Quality (EOSQ) across all products.
• Total bacterial counts ranged from 7.40-14.35 log10 CFU/g, greatly exceeding the EOSQ limit of 6 log10 CFU/g indicating poor hygiene and storage.
• LAB ranged from 2.47-4.60 log10 CFU/g, within the typical natural meat flora range.
• Coliforms were extremely high across all samples (5.9-11.45 log10 CFU/g), surpassing the 4 log10 CFU/g EOSQ limit which raises safety concerns of fecal contamination.
• Staphylococcus spp. also exceeded the EOSQ limit of 2 log10 CFU/g in all meats (4.75- 9.4 log10 CFU/g), suggesting human handling contamination.
• Yeasts & molds ranged between 5.15 and 9.7 (log10 CFU/g) in six types of meat products, which is higher than the EOSQ limit of (4 log10 CFU/g), indicating survival against preservatives or cross-contamination. The number in Sussis was only in the acceptable range (2.85 log10 CFU/g).
In conclusion, commercial processed meats tested in the present study showed very heavy microbial contamination indicating unhygienic practices during processing, handling, storage, and sales. The high microbial loads present risks of foodborne illnesses, toxicity, and spoilage before expiration. Strict quality control measures need implementation in Egyptian meat production chains, encompassing Good Manufacturing Practices, temperature control, effective preservatives, sanitation, and employee hygiene. Routine microbiological testing should be enforced to ensure safety.
1.2 Pathogenic bacteria in the commercial meat products.
The presence of four major foodborne pathogens, (Salmonella/Shigella spp., Bacillus cereus, Campylobacter spp. and Listeria spp.) were investigated in the 7 commercial meat products purchased from Egyptian markets, including beef burger, kofta, souses, sausage, minced meat, pastrami, and beef luncheon.
• Salmonella/Shigella were detected in 81% of Beef burger and 70.8% of minced meat samples, indicating likely fecal contamination and posing a public health risk of salmonellosis from improper food handling.
• B. cereus was found in 69.3% of Beef burger, 40% of kofta, 82% of sausage, 30% of beef luncheon and 90% of minced meat, presenting a hazard for food poisoning by this bacterium.
• In contrast, Campylobacter spp. and Listeria spp. were not detected in any of the meat products, which may be attributed to inactivation by heat processing.
Overall, the high prevalence of Salmonella/Shigella and B. cereus in processed meats highlights the need for control measures during slaughter, meat processing, storage, and preparation to mitigate contamination. Implementation of Hazard Analysis Critical Control Points (HACCP) and Good Manufacturing Practices along with consumer education on proper cooking and hygiene are recommended to enhance the microbiological safety of processed meats in Egypt. Routine pathogen testing should be conducted for quality assurance and risk reduction.
1.3 Assessment of microbiological quality, physio-chemical characteristics and safety of the commercial Beef luncheon
Beef luncheon is commonly consumed in lunches globally and in Egypt owing to its favorable nutritional value, inexpensive pricing, acceptable taste, and easy to eat. To recognize further details regarding the production and handling of beef luncheon in Egypt, seventy luncheon samples were obtained from ten sources (LU01-LU10).
The microbiological characteristics of commercial Beef luncheon
The microbiological quality of 70 beef luncheon samples collected from 10 different sources in Egypt was evaluated. Total aerobic bacteria, lactic acid bacteria (LAB), coliforms, Staphylococcus sp, yeasts & molds were enumerated.
• Total aerobic counts ranged from 2.49 to 4.74 log10 CFU/g, exceeding the limit of 4 log10 CFU/g set by the Egyptian Organization for Standardization and Quality (EOSQ) in 3 sources.
• LAB counts ranged from 1.3 to 3.51 log10 CFU/g, with 1 source dominating at 3.51 log10 CFU/g, likely representing the natural meat microflora. In general, LAB were absent in 30% of samples.
• Total coliforms ranged from 1.49 to 3.87 log10 CFU/g, exceeding the EOSQ limit of 2 log10 CFU/g in 8 sources, indicating poor hygiene.
• Staphylococcus spp. ranged from 2 to 3.74 log10 CFU/g, present in all samples despite EOSQ standards requiring absence, suggesting human contamination during processing.
• Yeasts & molds ranged from 3.52 to 6.85 log10 CFU/g, exceeding the EOSQ limit of 2 log10 CFU/g in all sources, pointing to probable resistance to preservatives like natamycin.
Overall, the commercial beef luncheon samples tested showed high microbial loads for all groups analyzed, frequently surpassing EOSQ microbial safety limits. Total bacterial counts, coliforms, Staphylococcus and yeasts& molds present at unsafe levels are indicative of unhygienic practices during manufacturing, handling and storage, and insufficient prevention of microbial contamination.
Pathogenic bacteria in the commercial Beef luncheon
Pathogenic bacteria studied here include Salmonella/Shigella, Bacillus cereus, Campylobacter, and Listeria. Bacillus cereus was detected in 30% of all beef luncheon samples, specifically in 3 out of 10 sources. The results demonstrated the absence of other pathogens after moderate heat treatment during manufacturing indicating adequate inhibition of vegetative cells. Noting that the spores of Bacillus cereus bacteria can resist heat and then germinate and multiply in the final products.
The physicochemical characteristics of commercial Beef luncheon were as follows:
• The moisture content ranged from 52.7 to 63.6%, which were in the range of Codex for beef luncheon (should be around 60%).
• The protein content ranged from 11.8 to 14.4%, compared to 16% in Codex.
• The fat content ranged from 18 to 25.1%, which meets the accepted limit in Codex.
• It was observed in the samples collected from one of the sources that the protein percentage reached 14.4%, and the fat percentage was 18%, which indicates a high nutritional value of the products of this source.
• The pH ranged from 4.2 to 6.2.
Preservatives in commercial Beef luncheon
Potassium sorbate (E202), potassium benzoate (E212), natamycin (E235), nisin (E234), and nitrite (E250) were estimated in the present study.
• The concentrations of potassium sorbate in commercial beef luncheon samples ranged from 650 in LU01 to 1180 ppm in LU05. Forty percent of the tested commercial beef luncheon samples contained potassium sorbate at concentrations higher than those allowed in Codex (1000 ppm).
• Potassium benzoate ranged from 430 to 630 ppm, which were in the accepted range of Codex (not more than 1000 ppm)
• Natamycin in beef luncheon exceeded Codex limits in 4 samples (40-62 ppm), indicating inconsistent use among manufacturers and underscoring the need for enhanced quality control for regulatory compliance.
• Nisin found in two beef luncheon samples (LU04 and LU10) complied with the Codex limit of 25 ppm.
• All beef luncheon samples had nitrite, ranging from 9 to 80 ppm. LU09 reached the Codex limit, emphasizing regulatory adherence.
Overall, some quality issues were identified in commercial beef luncheon samples, with total bacteria, coliforms, staphylococci, yeast, and molds exceeding permissible limits in most samples. The presence of Bacillus cereus in a number of samples was concerning. Physicochemical parameters were variable. The results also indicated the improper use of some preservatives such as potassium sorbate and natamycin.
Part II: Processing of Beef luncheon at laboratory scale.
2.1 Antimicrobial potential of essential oils
• The antimicrobial activity of 7 plant-derived essential oils (thyme, cumin, garlic, ginger, cinnamon, rosemary, turmeric) was tested against common foodborne pathogens (Escherichia coli ATCC 6933, Salmonella typhimurium ATCC 14028, Staphylococcus aureus ATCC 20231, Bacillus cereus ATCC 33018) using a well diffusion assay. The large inhibition zones indicate potent antibacterial effects.
• Thyme essential oil showed the strongest and broadest spectrum of antibacterial activity, with significant inhibition against all four bacteria tested: Salmonella typhimurium (22.0 mm zone), Staphylococcus aureus (17.0 mm), E. coli (16.0 mm), and B. cereus (23.0 mm).
• Cumin essential oil also exhibited significant broad spectrum antibacterial activity, though slightly less than thyme oil. It showed large inhibition zones against Salmonella typhimurium (21.0 mm), Staphylococcus aureus (16.0 mm), E. coli (12.0 mm), and B. cereus (22.0 mm).
• Rosemary essential oil displayed potent antibacterial effects specifically against Staphylococcus aureus, with an inhibition zone of 13.0 mm. This indicates rosemary oil’s significant potency against Gram-positive cocci bacteria like Staphylococcus.
• Garlic essential oil showed selective and substantial inhibitory effects against Salmonella typhimurium, with a zone of 7.0 mm.
• Ginger essential oil exhibited appreciable antibacterial effects against E. coli, with an inhibition zone of 12.0 mm.
• The results demonstrated that thyme and cumin oils have the greatest potential as natural antibacterial agents to inhibit foodborne pathogens and extend shelf-life of products like meat.
• Overall, this experiment highlights the potential of plant-derived essential oils, particularly thyme and cumin, as natural preservatives to enhance the microbial quality and safety of foods.
2.2 Minimum inhibitory concentration of the essential oils
• Thyme and cumin essential oils were chosen due to their wide range of effects on the studied pathogenic bacteria, to estimate the minimum inhibitory concentration (MIC).
• The MIC of thyme and cumin essential oils against Salmonella typhimurium, E. coli, Staphylococcus aureus and B. cereus was 0.125% based on agar diffusion assay results.
• No inhibition zone was observed at 0.0625% concentration
2.3 Application of predictive ComBase models to predict the survival of some microbial hazards in Beef luncheon production
• ComBase predictive models were used to evaluate the effects of nisin concentration (50, 100, 150 ppm), pH (4.0, 4.5, 5.0) and storage time (0, 7, 14 days) at 5°C on inhibiting growth of E. coli, Salmonella typhimurium, Staphylococcus aureus and B. cereus.
• The models predicted 50-100 ppm nisin effectively inhibited all bacteria tested.
• Lower pH of 4.0-4.5 was more effective than pH 5.0 for restricting growth of E. coli, Salmonella and Staph aureus.
• Longer 14-day storage resulted in lower maximum growth rates for B. cereus.
• The models predicted maximum growth rates ≤0.008 log10 CFU/ml/h under the conditions tested, indicating inhibited pathogen growth.
• The models provide useful guidance for formulation and processing parameters to inhibit pathogens and improve safety of products like luncheon meat.
2.4 Beef luncheon processing
Beef luncheon samples were produced with different antimicrobial treatments including thyme/cumin essential oils (EOs), nisin, and combinations of there. Samples were stored at 5°C for 90 days and analyzed for microbial quality and proximate composition over time.
Microbial quality
• All antimicrobial treatments inhibited Staph. aureus growth during storage, with complete elimination on day45 in the presence of thyme EOs, cumin EOs or nisin.
• Complete elimination of Staph. aureus was also achieved on day 30 when essential oils were compared with nisin at studied concentrations (50 and 100 ppm)
• All treatments suppressed B. cereus, with full inhibition by day 30 (thyme EOs), day 14 (cumin EOs/nisin) or day 7 (EOs-nisin combinations).
• Thyme EOs, cumin EOs, nisin and combinations reduced E. coli counts during storage, achieving complete inhibition within 7-30 days. EOs-nisin combinations showed the fastest effects.
• Natural antimicrobials lowered Salmonella levels over time, with elimination by day 14 (thyme EOs), day 7 (cumin EOs), day 14-30 (nisin) or day 7 (EOs-nisin combinations).
• Overall, combinations of EOs and nisin exhibited synergistic antibacterial effects, providing the most rapid and potent inhibition of all pathogens tested compared to individual treatments.
The physicochemical characteristics of Beef luncheon
• Moisture content remained similar to control over storage around 57 - 60%, within Codex specifications. EOs-nisin combinations increased moisture late in storage.
• Fat levels stayed consistent around 20%, indicating minimal oxidation effects. Cumin EOs and thyme-nisin lowered fat at some timepoints.
• Protein content remained stable around 15%, meeting Codex standard. Treatments had negligible effects.
• pH was unaffected by most treatments, staying around 5.4. Thyme EO and combinations lowered pH to 4.0-4.9.
Generally, natural antimicrobials effectively controlled pathogenic bacteria growth while maintaining acceptable proximate composition in beef luncheon during 90 day refrigerated storage. Combinations of essential oils and nisin provided optimal microbiological quality and safety.
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Part III: Suggestion of HACCP plan for Beef luncheon production.
The hazard analysis identified biological hazards like pathogens as high risk in raw materials, grinding, and cooling steps.
Five critical control points (CCPs) were identified:
CCP-C1- Raw Meat Receiving: Critical limits for pathogen levels and testing control biological hazards.
CCP-C2- Ingredients: Testing controls chemical hazards in ingredients.
CCP-P1: Forming Inspection prevents physical hazards like metal fragments.
CCP-B1- Grinding/Mixing: Controls like salting and hygiene prevent microbial growth.
CCP-B2- Packaging: Inspection ensures packaging integrity to prevent microbial contamination.
CCP-B3- Cooling: Temperature controls prevent microbial growth.
Prerequisite programs for supplier control, sanitation, and maintenance control hazards. Preventive measures at CCPs include supplier approval, microbial testing of raw materials, sanitation procedures, heat treatment parameters, rapid cooling, and packaging integrity checks. Ongoing monitoring of finished products for pathogens, pH, water activity, and preservatives is required. Implementation of HACCP with strict hygienic practices, cleaning procedures, and preventative process control at each CCP will mitigate hazards in beef luncheon production.
Conclusions
1. Commercial processed meats tested in the present study showed very heavy microbial contamination indicating unhygienic practices during processing, handling, storage, and sales.
2. The potential of plant-derived essential oils, particularly thyme and cumin, as natural preservatives to enhance the microbial quality and safety of foods.
3. Combinations of EOs and nisin exhibited synergistic antibacterial effects, providing the most rapid and potent inhibition of all pathogens tested compared to individual treatments. provided optimal microbiological quality and safety of food.
Recommendations
1. Routine microbiological testing should be enforced to ensure safety.
2. Strict quality control measures need implementation in Egyptian meat production chains, encompassing Good Manufacturing Practices, temperature control, effective preservatives, sanitation, and employee hygiene.
3. Implementation of HACCP with strict hygienic practices, cleaning procedures, and preventative process control at each CCP will mitigate hazards in beef luncheon production.