Comparative Study of Bacteriological and Organoleptic Properties of White Pickled Cheese Produced Using Calf Rennet
Abstract
An experiment was conducted on making white pickled cheese with Jiben (Solanumdubium) seed extracts and rennet as a control. Cheese produced using Jiben seed extracts and calf rennet were ripened in whey containing 15 % salt (NaCl), kept in sealed glass jars for 5 months at room 30°C and refrigerator 5±1°C temperatures. Cheese samples were taken during pickling for microbiological analysis (total count, coliforms/ fecal coliforms, molds and yeasts) and organoleptic properties. Results demonstrated that no differences in cheese quality and organoleptic properties for treated cheeses and the control. The microbial evaluation of both cheeses revealed a gradual decrease in Log No/g during ripening period. Total coliforms molds and yeasts were completely inhibited after 45 and 30 days of storage respectively. Staphylococcus aureusand fecal coliforms were not found during the investigation period. The organoleptic properties scores throughout the pickling period revealed that, scores of the cheeses increased as the pickling period progress in both types of cheeses. It could be used Jiben seed extracts as a milk coagulant
Introduction
ennet is a general term that describes a variety of enzymes of animals (especially calves) plant or microbial origin used to coagulate milk during cheese making [1]. Renin, an acid proteinase present in the abomasum of young ruminants, shows a highly specific milk clotting activity relative to its proteolytic activity. The limited supply of rennet and its resulting high price have necessitated for many decades, to come up with an alternative milk coagulant [2].
Cyprosins (Cynarases) are aspartic proteinases present in the aqueous extract of Cardoon (Cynaracardunculus L.) flowers used as milk coagulant for the manufacture of some Portuguese and Spanish traditional cheeses [3].The milk clotting enzyme from the latex, stem and leaves of Sodom apple (Calotropisprocera) has been used traditionally in Nigeria for the manufacture of a soft bodied cheese called Warankasi[4]. A longer rennet coagulation time (firmer coagulum at cutting) resulted in an increase in cheese moisture as well as an increase in cheese yield [5].
White brined cheese produced from bovine and caprine milks accounted for approximately 51% of world cheese production in 1992 [6].The microbiological safety of Feta and related cheeses is not surprising, for their popularity in warm climates suggests that the combination of acidity and salt are well suited for the storage of cheese in a state that is safe for the consumer [7].
White pickled cheese is usually made from raw milk and contains 6-20% NaCl [8,9]. The purpose of the high salt concentration is to control the microflora found in milk, particularly the pathogens. However, salt has a major influence on acid development and rennet coagulation [10]. [11] found at the end of ripening CanestratoPuglese cheese made from raw or pasteurized milk, contained less than 1.0 cfu/g of total and faecal coliforms, Escherichia coli and Staphylococcus aureuswere not detected. In brined cheeses, high salt in moisture concentrations or high acidities may be the key features, with the contrasted low acidities and modest salt contents acting, respectively, as additional hurdles to the growth and survival of vegetative pathogens [7].The inhibitory anion of the low pH and high salt- in moisture values that are typical of brined cheeses tends to lead to a rapid reduction in the counts of Staphylococci, and coliforms [12]. The study was designed to determine the shelf life and keeping quality of white pickled cheese produced using Jiben seed extracts and rennet as coagulants.