LPT 321: Meat Science (1+1)

PRESERVATION BY USE OF ANTIBIOTICS

• The antibiotics when used in the required concentration impart no flavour or odour to the meat and do not discolour the product, while most of them are considered relatively harmless to humans.
• Broad-spectrum antibiotics such as Chlortetracycline, Oxytetracycline and Chloramphenicol are commonly used.
• Infusion of beef carcasses with tetracycline antibiotics seems to have improved their keeping quality and retarded internal spoilage.
• Antibiotics can also be injected into the living animal just prior to slaughter.
• Administration may either intravenously or intraperitoneally  of the animal.
• But, the intraperitoneal is commercially impossible (impracticable) because of the time factor, which cannot be easily offered in commercial slaughter practice.
• It is, however, a procedure, which could be adopted in countries lacking refrigeration and thus making possible for the meat to be distributed to a much wide area than at present.
• These antibiotics are also used in the preservation of foods such as poultry and fish also.
• The antibiotics are added to water in a proportion of 5 to 40 ppm and poultry dipped into treated water for chilling.
• Alternatively, the antibiotics are added to ice in amounts of 2 to 5 ppm.
• Chicken is soaked in this ice and water. Such methods have been seen to increase the shelf life of the foods considerably.
• An important objection to inclusion of antibiotics in meat is that, it will create antibiotic resistant strains of pathogenic bacteria.
• Yet, another objection is that, the antibiotics are ineffective against yeast and moulds.
• There is also the danger that, producer, may be tempted to supplement good ideal practice under antibiotic cover.
• Chloramphenicol and Streptomycin are somewhat toxic.
• Penicillin produces hypersensitivity.
• Streptomycin, polymixin and subtalin have limited anti-bacterial spectra.
• Antibiotics should not be used to replace good hygiene, but when employed such that all the above dangers are avoided, and in conjunction with mild refrigeration or pasteurising doses of irradiation they afford a means of preservation without materially altering the product.
• However, preservation of foods using antibiotics has been banned in many countries due to public health concern.

Sl.No.	Name of antibiotic	Active against	Effective pH range	Stability
1.	Chlortetracycline -	Gram + ve and – ve	4 to 7	2 Weeks at pH at 4°C. Rapid deterioration over pH 7
2.	Oxytetracycline -	-do-	-do-	One month at pH 3.9 at 5°C. Rapid deterioration above pH 7.0 unless refrigerated.
3.	Penicillin	Gram + ve only.	5 to 7	2 days at pH 6.0 at 10°C. Rapid deterioration below pH 5.0 or above 7.0.
4.	Streptomycin and dihydrostreptomycin	Gram – ve o nly	7 to 9	2 to 3 months at pH 4 to 7 at below 7°C.
5.	Polymixin	Gram –ve only	4 to 8	2 months at pH 6.0.